Annual Report of the Secretary of the Navy, 1919 -- Miscellaneous Reports

Influenza

Annual Report of the Secretary of the Navy, 1919 -- Miscellaneous Reports.

Section 1 - Section 2 - Section 3

INFLUENZA STATISTICS, ENTIRE NAVY.

The following tables contain statistics for the entire Navy:

Table No. 8 shows admissions and annual admission rates per 1,000 of complement by weeks, for influenza, pneumonia (all forms), bronchitis and all these causes combined, for the entire Navy for the whole calendar year 1918.

Table No. 9 shows admissions and annual admission rates per 1,000 of complement by weeks, calendar year, 1918, for influenza, pneumonia (all forms), bronchitis, and these causes combined, for the forces of the United States Navy ashore in the United States.

Table No. 10 shows admissions and annual admission rates per 1,000 of complement by weeks, calendar year, 1918, for influenza, pneumonia (all forms), bronchitis, and these causes combined, for the forces of the United States Navy afloat and expeditionary forces, including marines and expeditionary forces in the Navy in Europe. It has not been possible to secure accurate complement figures separately for the forces afloat and the naval or marine corps forces ashore in Europe.

Table No. 11 shjows deaths and annual death rates per 1,000 of complement by weeks, calendar year 1918, for influenza (including influenzal pneumonia) and pneumonia (all other forms) for the entire Navy.

Table No. 12 shows deaths and annual death rates per 1,000 of complement by weeks, calendar year 1918, for influenza (including influenzal pneumonia and pneumonia (all other forms) for the United States naval forces ashore in the United States.

Table No. 13 shows deaths and annual death rates per 1,000 of complement by weeks, calendar year 1918, for influenza (including influenzal pneumonia) and pneumonia (all other forms) for the United States naval forces afloat and the expeditionary forces of the Navy, including marines, combined. It has not been possible to secure accurate complement figures separately for the forces afloat and naval or Marine Corps forces ashore in Europe.

Chart No. 15 shows the incidence and prevalence of influenza and death rates by weeks in the Navy during the whole calendar year 1918. As indicated, the death rate from influenza (including influenzal pneumonia), expressed in terms of an annual rate per 1,000 of complement, did not rise above 1 in any week until the week ending

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September 6, when it was 2 for the force ashore. The curves indicating admission rates show clearly the prevalence of influenza in the spring months not only among the naval forces afloat and in Europe but also among those in the United States. Diminished prevalence among all forces in July and August is very noticeable.

Image of CHART 15.--Logarithmic scale. United States Navy: Annual admission rates and annual death rates per 1,000 of complement, by weeks, calendar year 1918; influenza, including influenzal pneumonia.

CHART 15.--Logarithmic scale. United States Navy: Annual admission rates and annual death rates per 1,000 of complement, by weeks, calendar year 1918; influenza, including influenzal pneumonia.

Chart No. 16 shows annual death rates per 1,000 of complement by weeks, calendar year 1918, for pneumonia (all forms including influenzal pneumonia) for the entire Navy and separately for the forces ashore in the United States and all other forces, afloat, ashore at foreign stations, and expeditionary forces. While the death rate from influenza did not exceed 1 per 1,000 (annual rate) for any week prior to September 1, as indicated by chart No. 15, the combined rates for influenza and pneumonia (all forms) exceeded this figure nearly every week during January, February, March, April, and May, after which the combined rate, entire Navy, did not exceed this figure until the week ending September 7. Even for the forces ashore in the United States the rate for influenza alone did not exceed 1 per 1,000 until the latter date, although the all-pneumonia rate was occasionally higher than 1 during June, July, and August.

It is very likely that at least some of the deaths from pneumonia in cases where influenza was not considered in diagnosis during

--2441--

Image of Chart 16.--Logarithmic scale. United States Navy: Annual death rates per 1,000 of complement, by weeks, calendar year 1918; pneumonia, all forms, including influenzal pneumonia.

Chart 16.--Logarithmic scale. United States Navy: Annual death rates per 1,000 of complement, by weeks, calendar year 1918; pneumonia, all forms, including influenzal pneumonia.

--2442--

January, February, March, and April were primarily due to influenza, and that the outbreaks of this disease which occurred in the late winter and spring were by no means so benign as the figures for influenza now obtainable would indicate.

Table No. 14 shows the distribution of influenza cases and specific admission rates per 1,000 living, according to age groups, enlisted personnel of the Navy, by months, during the period September 1 to December 31, 1918.

Table No. 15 contains similar date for pneumonia (all forms).

Image of Chart 17.--Specific admission rates and specific death rates per 1,000 living, for influenza, including influenzal pneumonia, and for pneumonia (all forms other than influenzal pneumonia), according to age groups, enlisted personnel of the Navy, September 1 to December 31, 1918.

Chart 17.--Specific admission rates and specific death rates per 1,000 living, for influenza, including influenzal pneumonia, and for pneumonia (all forms other than influenzal pneumonia), according to age groups, enlisted personnel of the Navy, September 1 to December 31, 1918.

Table No. 16 shows the distribution of deaths from influenza, including influenzal penumonia, among age groups and specific death rates per 1,000 living, by months, enlisted personnel of the Navy, during the period September 1 to December 31, 1918.

Table No. 17 shows deaths and specific death rates per 1,000 living, for pneumonia (all forms other than influenzal pneumonia), by months, according to age groups, enlisted personnel of the Navy, during the period September 1 to December 31, 1918.

Table No. 18 shows case-fatality rates for influenza, including influenzal pneumonia and pneumonia (all other forms), according to age groups.

Admission rates and death rates for several age groups, enlisted personnel, period September 1 to December 31, 1918, are shown in chart No. 17.

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TABLE No. 8.--Entire Navy: Admissions and annual admission rates per 1,000 by weeks, 1918, influenza, pneumonia (all forms), bronchitis.

Week.	Comple- ment.	Influenza.		Pneumonia (all forms).		Bronchitis.		Total
Week.	Comple- ment.	Case.	Rate.	Case.	Rate.	Case.	Rate.	Case.	Rate.
Jan. 5	329,878	502	79.04	105	16.12	276	43.16	883	138.84
Jan. 12	336,567	634	97.76	159	24.44	336	51.48	1,129	174.20
Jan. 19	343,256	607	91.52	174	26.00	299	45.24	1,080	163.28
Jan. 26	349,945	680	100.88	146	21.32	273	40.56	1,099	163.28
Feb. 2	356,634	648	94.12	135	19.24	312	45.24	1,095	159.64
Feb. 9	363,323	903	128.96	136	19.24	259	36.92	1,298	185.64
Feb. 16	370,012	815	114.40	112	15.60	319	44.72	1,246	174.72
Feb. 23	376,701	968	133.12	123	16.64	232	31.72	1,323	182.52
Mar. 2	383,390	1,473	199.68	193	26.00	259	34.84	1,925	260.52
Mar. 9	390,079	1,402	186.68	215	28.60	282	37.44	1,899	252.72
Mar. 16	396,768	1,465	191.88	211	27.56	231	30.16	1,907	249.60
Mar. 23	403,457	1,307	167.96	162	20.80	197	24.96	1,666	214.24
Mar. 30	410,146	1,216	153.92	119	15.08	199	24.96	1,534	194.48
Apr. 6	416,835	1,290	160.68	138	17.16	207	25.48	1,635	203.84
Apr. 13	423,524	1,111	136.24	236	28.60	198	23.92	1,545	189.28
Apr. 20	430,213	1,044	122.20	116	13.52	153	18.20	1,283	154.96
Apr. 27	436,902	649	76.96	93	10.92	173	20.28	915	108.68
May 4	443,591	917	107.12	83	9.36	158	18.20	1,158	135.72
May 11	450,280	848	97.76	84	9.36	160	18.20	1,092	125.84
May 18	456,969	675	76.44	60	6.76	164	18.20	899	101.92
May 25	463,658	531	59.28	54	5.72	166	18.20	751	83.72
June 1	470,347	583	63.96	47	4.58	130	14.04	760	83.72
June 8	477,036	549	59.77	49	5.20	124	13.00	722	78.52
June 15	483,725	640	68.64	35	3.64	140	14.56	815	87.36
June 22	490,414	575	60.84	36	3.64	143	15.08	754	79.56
June 29	497,103	816	85.28	32	3.12	174	18.20	1,022	106.60
July 6	503,792	773	79.56	39	3.64	133	13.52	945	97.24
July 13	510,481	954	96.72	47	4.68	147	14.56	1,148	116.48
July 20	517,170	720	72.28	50	4.68	150	15.08	920	92.04
July 27	523,859	613	60.84	50	4.68	213	20.80	876	86.84
Aug. 3	530,548	623	60.84	35	3.12	197	19.24	855	83.72
Aug. 10	537,237	468	45.24	57	5.20	171	16.12	696	67.08
Aug. 17	543,926	489	46.28	63	5.72	226	21.32	778	74.36
Aug. 24	550,615	528	49.40	43	3.64	264	24.44	835	78.52
Aug. 31	557,304	762	70.72	53	4.68	246	22.88	1,061	98.80
Sept. 7	563,993	1,314	120.64	70	6.24	268	24.44	1,652	151.84
Sept. 14	570,682	5,568	507.00	153	13.52	358	32.24	6,079	553.80
Sept. 21	577,371	17,233	1,551.68	1,016	91.00	337	30.16	18,586	1,673.88
Sept. 28	584,060	16,117	1,434.68	2,112	187.72	529	46.80	18,758	1,669.72
Oct. 5	590,749	13,800	1,214.72	1,863	163.80	523	45.76	16,186	1,424.28
Oct. 12	597,438	9,041	786.76	1,090	94.64	434	37.44	10,565	919.36
Oct. 19	604,127	6,396	550.16	790	67.60	327	28.08	7,513	646.36
Oct. 26	610,816	4,418	375.96	364	30.68	296	24.96	5,078	432.12
Nov. 2	617,505	3,809	320.32	299	24.96	296	24.44	4,404	370.76
Nov. 9	624,205	2,596	215.80	176	14.56	307	25.48	3,079	256.36
Nov. 16	624,205	2,152	178.88	136	10.92	377	31.20	2,665	221.52
Nov. 23	624,205	1,709	141.96	158	13.00	352	29.12	2,219	184.60
Nov. 30	624,205	1,257	104.52	81	6.24	356	29.64	1,694	140.92
Dec. 7	624,205	1,411	117.52	93	7.28	428	35.36	1,932	160.68
Dec. 14	624,205	1,734	144.04	147	11.96	503	41.60	2,384	198.21
Dec. 21	620,000	1,598	133.64	136	10.92	378	31.20	2,112	176.80
Dec. 28	614,000	1,075	91.00	97	7.80	270	22.36	1,442	121.68
Dec. 29-31	614,000	428	84.18	35	6.10	86	17.08	549	108.58
Total	503,792	120,404	238.99	12,306	24.42	13,736	27.26	146,446	290.63

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TABLE No. 9.--United States Navy forces ashore in the United States Admissions and annual admission rates per 1,000 by weeks, 1918, influenza, pneumonia (all forms), bronchitis.

Week.	Comple- ment.	Influenza.		Pneumonia (all forms).		Bronchitis.		Total
Week.	Comple- ment.	Case.	Rate.	Case.	Rate.	Case.	Rate.	Case.	Rate.
Jan. 5	106,693	281	136.24	81	39.00	185	89.44	547	265.72
Jan. 12	112,262	361	166.92	121	55.64	236	109.20	718	382.28
Jan. 19	107,978	339	162.76	130	62.40	196	94.12	665	319.80
Jan. 26	104,858	368	182.00	117	57.72	185	91.52	670	331.76
Feb. 2	105,089	364	179.92	102	50.44	223	110.24	689	340.60
Feb. 9	103,168	450	226.72	99	49.40	179	89.96	728	366.60
Feb. 16	100,716	440	226.72	79	40.56	239	123.24	758	391.04
Feb. 23	102,018	441	224.64	90	45.76	165	83.72	696	354.64
Mar. 2	105,232	56-	276.64	144	70.72	169	83.80	873	431.08
Mar. 9	106,648	595	290.16	145	70.72	166	80.60	906	441.48
Mar. 16	111,257	674	314.60	132	61.36	136	63.44	942	439.92
Mar. 23	106,557	591	288.08	99	48.36	128	62.40	818	398.84
Mar. 30	107,821	600	289.12	87	41.60	125	59.80	812	391.56
Apr. 6	110,782	657	307.84	100	46.80	131	61.36	888	416.52
Apr. 13	111,942	616	287.04	196	91.00	115	53.04	927	430.56
Apr. 20	114,400	745	338.52	77	34.84	81	36.40	903	410.28
Apr. 27	118,090	398	175.24	71	31.20	125	54.60	594	261.56
May 4	112,968	377	173.16	51	23.40	84	38.48	512	235.56
May 11	121,246	320	136.76	52	21.84	103	43.68	475	203.32
May 18	122,401	209	88.40	39	16.12	96	40.56	344	146.12
May 25	126,855	216	88.40	33	13.52	102	41.60	351	143.52
June 1	132,434	236	92.56	30	11.44	73	28.60	339	132.60
June 8	139,267	211	78.52	27	9.88	80	29.64	318	118.56
June 15	148,282	240	83.72	16	5.20	100	34.84	356	124.80
June 22	154,248	187	62.92	25	8.32	99	34.28	311	104.52
June 29	159,415	236	76.76	26	8.32	119	38.48	381	123.76
July 6	166,456	295	92.04	28	8.32	82	25.48	405	126.36
July 13	171,215	217	65.52	29	8.32	102	30.68	348	105.56
July 20	175,116	203	59.80	35	9.88	102	30.16	340	100.88
July 27	186,093	157	43.68	32	8.84	149	41.60	338	94.12
Aug. 3	197,643	184	48.36	23	5.72	126	32.76	333	87.36
Aug. 10	206,020	197	49.40	43	10.40	116	29.12	356	89.44
Aug. 17	207,693	206	51.48	50	11.96	159	39.52	415	103.48
Aug. 24	214,019	257	62.40	31	7.28	166	40.04	454	110.24
Aug. 31	216,654	468	112.32	38	8.84	182	43.68	688	164.84
Sept. 7	220,339	869	204.88	44	9.88	188	44.20	1,101	258.48
Sept. 14	234,760	4,458	986.96	117	25.48	248	54.60	4,823	1,068.08
Sept. 21	247,954	14,380	3,015.48	825	172.64	205	42.64	15,410	3,231.28
Sept. 28	255,066	11,851	2,416.96	1,829	370.76	406	82.68	14,086	2,871.44
Oct. 5	254,676	9,776	1,993.68	1,593	325.00	387	78.52	11,7756	2,383.68
Oct. 12	255,421	5,757	1,171.56	878	178.36	295	59.80	6,930	1,410.76
Oct. 19	249,392	3,656	761.80	564	117.52	195	40.56	4,415	920.40
Oct. 26	250,831	2,509	520.00	223	45.76	217	44.72	2,949	611.00
Nov. 2	247,020	2,087	438.88	202	42.12	208	43.68	2,497	525.20
Nov. 9	246,313	1,940	409.24	120	24.96	192	40.04	2,252	475.28
Nov. 16	244,974	1,402	298.48	105	21.84	262	55.12	1,769	375.44
Nov. 23	243,385	1,051	224.12	132	28.08	242	51.48	1,425	304.20
Nov. 30	244,296	789	167.44	63	13.00	241	50.96	1,093	232.44
Dec. 7	245,858	1,052	222.04	66	13.52	317	66.56	1,435	303.16
Dec. 14	238,666	1,154	251.16	120	26.00	337	73.32	1,611	351.00
Dec. 21	239,313	913	197.60	101	21.84	239	51.48	1,253	271.44
Dec. 28	228,427	648	147.16	71	16.12	162	36.40	8881	200.20
Dec. 29-31	218,783	269	148.84	23	12.20	51	28.06	343	190.32
Total	193,818	77,457	399.63	9,554	49.29	9,216	47.54	96,227	496.48

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TABLE No. 10.--United States Navy forces afloat and expeditionary forces (including marines) combined: Admissions and annual admission rates per 1,000 by weeks, 1918, influenza, pneumonia (all forms), bronchitis.

Week.	Comple- ment.	Influenza.		Pneumonia (all forms).		Bronchitis.		Total
Week.	Comple- ment.	Case.	Rate.	Case.	Rate.	Case.	Rate.	Case.	Rate.
Jan. 5	222,895	221	51.48	24	5.20	91	20.80	336	78.00
Jan. 12	224,305	273	62.92	38	8.84	100	22.88	411	95.16
Jan. 19	235,278	268	58.76	44	9.36	103	22.36	415	91.52
Jan. 26	245,087	312	66.04	29	5.72	88	18.20	429	91.00
Feb. 2	251,545	284	58.24	33	6.76	89	18.20	406	83.72
Feb. 9	260,155	453	90.48	37	7.28	80	15.60	570	113.88
Feb. 16	269,296	375	72.28	33	6.24	80	15.08	488	94.12
Feb. 23	274,683	527	99.32	33	5.72	67	12.48	627	118.56
Mar. 2	278,158	913	170.56	49	8.84	90	16.64	1,052	196.56
Mar. 9	283,431	807	147.68	70	13.00	116	20.80	993	182.00
Mar. 16	285,511	791	144.04	75	13.52	95	17.16	961	174.72
Mar. 23	296,900	716	125.32	63	10.92	69	11.96	848	148.20
Mar. 30	302,325	616	105.56	32	5.20	74	12.48	722	123.76
Apr. 6	306,053	633	107.12	38	6.24	76	12.48	747	126.88
Apr. 13	311,582	495	82.16	40	6.24	83	13.52	618	102.96
Apr. 20	315,813	269	44.20	39	6.24	72	11.44	380	62.40
Apr. 27	318,812	251	40.56	22	3.12	48	7.80	321	52.00
May 4	330,623	540	86.32	32	4.68	74	11.44	646	101.40
May 11	329,034	528	85.28	32	4.68	57	8.84	617	97.24
May 18	334,568	466	72.28	21	3.12	68	10.40	555	85.80
May 25	336,803	315	48.36	21	3.12	64	9.88	400	61.26
June 1	337,913	347	53.04	17	2.60	57	8.32	421	64.48
June 8	337,769	338	52.00	22	3.12	44	6.76	404	61.88
June 15	335,443	400	61.88	19	2.60	40	5.72	459	70.72
June 22	336,166	388	59.80	11	1.56	44	6.76	443	68.12
June 29	337,688	530	81.12	6	.88	55	8.32	591	91.00
July 6	337,336	478	73.32	11	1.56	51	7.80	540	83.20
July 13	339,266	737	112.84	18	2.60	45	6.76	800	122.20
July 20	342,054	517	78.52	15	2.08	48	7.28	580	87.88
July 27	337,766	456	70.20	18	2.60	64	9.36	538	82.68
Aug. 3	332,905	439	68.12	12	1.56	71	10.92	522	81.12
Aug. 10	331,217	271	42.12	14	2.08	55	8.32	340	53.04
Aug. 17	336,233	283	43.16	13	1.56	67	9.88	363	55.64
Aug. 24	336,596	271	41.60	12	1.56	98	15.08	387	59.28
Aug. 31	340,650	294	44.72	15	2.08	64	9.36	373	56.68
Sept. 7	343,654	445	67.08	26	3.64	80	11.96	551	83.20
Sept. 14	335,922	1,110	171.60	36	5.20	110	16.64	1,256	193.86
Sept. 21	329,417	2,853	450.32	191	30.16	132	20.80	3,176	501.28
Sept. 28	328,994	4,266	673.92	283	44.72	123	19.24	4,672	738.40
Oct. 5	336,073	4,024	622.44	270	41.60	136	20.80	4,430	685.36
Oct. 12	342,017	3,284	499.20	212	31.72	139	20.80	3,635	552.24
Oct. 19	354,735	2,740	401.44	226	32.76	132	19.24	3,098	453.96
Oct. 26	359,985	1,909	275.60	141	20.28	79	10.92	2,129	307.32
Nov. 2	370,485	1,722	241.28	97	135.52	88	11.96	1,907	267.28
Nov. 9	377,892	656	89.96	56	7.28	115	15.60	827	113.36
Nov. 16	379,231	750	102.44	41	5.20	115	15.60	906	123.76
Nov. 23	380,820	658	89.44	26	3.12	110	14.56	794	108.16
Nov. 30	379,909	468	63.96	18	2.08	115	15.60	601	82.16
Dec. 7	378,347	359	48.88	27	3.64	111	15.08	497	68.12
Dec. 14	385,539	580	78.00	27	3.64	166	22.36	773	104.00
Dec. 21	380,687	685	93.08	35	4.68	139	18.72	859	117.00
Dec. 28	385,573	427	57.20	16	2.08	108	14.56	551	74.36
Dec. 29-31	395,217	159	48.80	12	3.66	35	9.76	206	63.44
Total	309,974	42,947	138.55	2,752	8.87	4,520	14.60	50,219	162.01

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TABLE No. 11.--Entire Navy: Deaths and annual death rates per 1,000 by weeks, 1918, influenza and pneumonia (all forms).

Week.	Comple- ment.	Influenza.		Pneumonia (all forms).		Total
Week.	Comple- ment.	Case.	Rate.	Case.	Rate.	Case.	Rate.
Jan. 5	329,878	------	------	6	0.93	6	0.93
Jan. 12	336,567	1	0.15	18	2.75	19	2.91
Jan. 19	343,256	------	------	21	3.17	21	3.17
Jan. 26	349,945	------	------	13	1.92	13	1.92
Feb. 2	356,634	1	.14	25	3.64	26	3.74
Feb. 9	363,323	------	------	18	2.54	18	2.54
Feb. 16	370,012	------	------	17	2.34	17	2.34
Feb. 23	376,701	------	------	22	3.01	22	3.01
Mar. 2	383,390	1	.13	22	2.96	23	3.06
Mar. 9	390,079	------	------	37	4.88	37	4.88
Mar. 16	396,768	1	.13	50	6.55	51	6.65
Mar. 23	403,457	------	------	40	5.14	40	5.14
Mar. 30	410,146	------	------	39	4.94	39	4.94
Apr. 6	416,835	1	.11	23	2.86	24	2.96
Apr. 13	423,524	------	------	19	2.28	19	2.28
Apr. 20	430,213	2	.23	20	2.39	22	2.65
Apr. 27	436,902	1	.11	22	2.60	23	2.70
May 4	443,951	------	------	9	1.04	9	1.04
May 11	450,280	2	.22	11	1.24	13	1.45
May 18	456,969	------	------	13	1.45	13	1.45
May 25	463,658	1	.10	5	.52	6	.62
June 1	470,347	------	------	7	.72	7	.72
June 8	477,036	1	.10	3	.32	4	.43
June 15	483,725	2	.20	1	.10	3	.32
June 22	490,414	------	------	6	.62	6	.62
June 29	497,103	1	.10	2	.20	3	.31
July 6	503,792	1	.09	2	.20	3	.30
July 13	510,481	------	------	3	.30	3	.30
July 20	517,170	------	------	8	.72	8	.72
July 27	523,859	2	.19	3	.29	5	.49
Aug. 3	530,548	2	.19	1	.09	3	.29
Aug. 10	537,237	------	------	5	.48	5	.48
Aug. 17	543,926	------	------	8	.72	8	.72
Aug. 24	550,615	1	.09	4	.37	5	.46
Aug. 31	557,304	1	.09	3	.27	4	.36
Sept. 7	563,993	9	.78	4	.36	13	1.19
Sept. 14	570,682	38	3.43	12	1.09	50	4.52
Sept. 21	577,371	266	23.92	14	1.24	280	24.96
Sept. 28	584,060	989	87.88	64	5.20	1,053	93.60
Oct. 5	590,749	802	70.20	43	3.74	845	74.36
Oct. 12	597,438	655	56.68	26	2.23	681	58.76
Oct. 19	604,127	478	41.08	21	1.76	499	42.64
Oct. 26	610,816	248	20.80	13	1.09	261	21.84
Nov. 2	617,505	170	14.08	2	.16	172	14.35
Nov. 9	624,205	102	8.32	2	.16	104	8.63
Nov. 16	624,205	80	6.24	3	.24	83	6.76
Nov. 23	624,205	71	5.72	4	.33	75	6.24
Nov. 30	624,205	43	3.53	1	.08	44	3.64
Dec. 7	624,205	33	2.70	11	.88	44	3.64
Dec. 14	624,205	42	3.48	8	.62	50	4.16
Dec. 21	620,000	44	3.64	10	.83	54	4.52
Dec. 28	614,000	50	4.21	4	.32	54	4.52
Dec. 29-31	614,000	16	3.17	1	.19	17	3.29
Total	503,792	4,158	8.25	749	1.48	4,907	9.73

--2447--

TABLE No. 12.--United States naval forces ashore in the United States; Deaths and annual death rates per 1,000 by weeks, 1918, influenza and pneumonia (all forms).

Week.	Comple- ment.	Influenza.		Pneumonia (all forms).		Total
Week.	Comple- ment.	Case.	Rate.	Case.	Rate.	Case.	Rate.
Jan. 5	106,983	------	------	4	1.92	4	1.92
Jan. 12	112,262	1	0.46	10	4.62	11	5.04
Jan. 19	107,978	------	------	18	8.32	18	8.32
Jan. 26	104,858	------	------	11	5.40	11	5.40
Feb. 2	105,089	1	.49	23	10.92	24	11.85
Feb. 9	103,168	------	------	13	6.24	13	6.24
Feb. 16	100,716	------	------	7	3.58	7	3.58
Feb. 23	102,018	------	------	19	9.36	19	9.36
Mar. 2	105,232	1	.49	15	7.28	16	7.80
Mar. 9	106,648	------	------	20	9.36	20	9.36
Mar. 16	111,257	------	------	31	14.04	31	14.04
Mar. 23	106,557	------	------	23	10.92	23	10.92
Mar. 30	107,821	------	------	17	7.80	17	7.80
Apr. 6	110,782	------	------	16	7.28	16	7.28
Apr. 13	111,942	------	------	12	5.20	12	5.20
Apr. 20	114,400	------	------	8	3.58	8	3.58
Apr. 27	118,090	1	.43	17	7.28	18	7.80
May 4	112,968	------	------	6	2.75	6	2.75
May 11	121,246	2	.83	7	2.96	9	3.84
May 18	122,401	------	------	8	3.38	8	3.38
May 25	126,855	1	.41	2	.78	3	1.19
June 1	132,434	------	------	5	1.92	5	1.92
June 8	139,267	1	.36	1	.36	2	.72
June 15	148,282	1	.35	1	.34	2	.67
June 22	154,248	------	------	4	1.30	4	1.30
June 29	159,415	------	------	------	------	------	------
July 6	166,456	1	.31	1	.31	2	.62
July 13	171,215	------	------	3	.88	3	.88
July 20	175,116	------	------	4	1.14	4	1.14
July 27	186,093	------	------	1	.27	1	.27
Aug. 3	197,643	------	------	1	.26	1	.26
Aug. 10	206,020	------	------	3	.72	3	.72
Aug. 17	207,693	------	------	6	1.45	6	1.45
Aug. 24	314,019	------	------	3	.72	3	.72
Aug. 31	216,654	------	------	2	.47	2	.47
Sept. 7	220,339	8	1.87	3	.67	11	2.54
Sept. 14	234,760	33	6.76	10	2.18	43	9.36
Sept. 21	247,954	225	46.80	11	2.08	236	48.40
Sept. 28	255,066	841	171.08	39	7.80	880	178.88
Oct. 5	254,676	623	126.88	28	5.20	651	132.60
Oct. 12	255,421	496	100.88	19	3.84	515	104.52
Oct. 19	249,392	313	65.00	19	3.95	332	69.16
Oct. 26	250,831	145	29.64	5	.98	150	30.68
Nov. 2	247,020	97	20.28	2	.41	99	20.80
Nov. 9	246,313	70	14.56	1	.20	71	14.76
Nov. 16	244,974	56	11.44	1	.20	57	11.96
Nov. 23	243,385	54	11.44	3	.62	57	11.96
Nov. 30	244,296	33	6.76	------	------	33	6.76
Dec. 7	245,858	27	5.20	9	1.87	36	7.28
Dec. 14	238,666	33	6.76	5	1.04	38	7.80
Dec. 21	239,313	35	7.28	7	1.50	42	8.84
Dec. 28	228,427	41	8.84	2	.45	43	9.36
Dec. 29-31	218,783	12	6.58	------	------	12	6.58
Total	193,818	3,152	16.26	486	2.57	3,638	18.77

--2448--

TABLE No. 13.--United States naval forces afloat and expeditionary forces (including Marines) combined: Deaths and annual death rates per 1,000 by weeks, 1918, influenza and pneumonia (all forms).

Week.	Comple- ment.	Influenza.		Pneumonia (all forms).		Total
Week.	Comple- ment.	Case.	Rate.	Case.	Rate.	Case.	Rate.
Jan. 5	222,895	------	------	2	0.46	2	0.46
Jan. 12	224,305	------	------	8	1.82	8	1.82
Jan. 19	235,278	------	------	3	.62	3	.62
Jan. 26	245,087	------	------	2	.41	2	.41
Feb. 2	251,545	------	------	2	.41	2	.41
Feb. 9	260,155	------	------	5	.98	5	.98
Feb. 16	269,296	------	------	10	1.92	10	1.92
Feb. 23	274,683	------	------	3	.52	3	.52
Mar. 2	278,158	------	------	7	1.30	7	1.30
Mar. 9	283,431	------	------	17	3.06	17	3.06
Mar. 16	285,511	1	0.18	19	3.43	20	3.64
Mar. 23	296,900	------	------	17	2.96	17	2.96
Mar. 30	302,325	------	------	22	3.74	22	3.74
Apr. 6	306,053	1	.16	7	1.14	8	1.35
Apr. 13	311,582	------	------	7	1.14	7	1.14
Apr. 20	315,813	2	.32	12	1.92	14	2.28
Apr. 27	318,812	------	------	5	.78	5	.78
May 4	330,623	------	-----	3	.46	3	.46
May 11	329,034	------	------	4	.62	4	.62
May 18	334,568	------	------	5	.72	5	.72
May 25	336,803	------	------	3	.45	3	.45
June 1	337,913	------	------	2	.30	2	.30
June 8	337,769	------	------	2	.30	2	.30
June 15	335,443	1	.15	------	------	1	.15
June 22	336,166	------	------	2	.30	2	.30
June 29	337,688	1	.15	2	.30	3	.45
July 6	337,336	------	------	1	.15	1	.15
July 13	339,266	------	------	------	------	------	------
July 20	342,054	------	------	4	.57	4	.57
July 27	337,766	2	.30	2	.30	4	.57
Aug. 3	332,905	2	.31	------	------	2	.31
Aug. 10	331,217	------	------	2	.31	2	.31
Aug. 17	336,233	------	------	2	.30	2	.30
Aug. 24	336,596	1	.15	1	.15	2	.30
Aug. 31	340,650	1	.15	1	.15	2	.30
Sept. 7	343,654	1	.15	1	.15	2	.30
Sept. 14	335,922	5	.72	2	.30	7	1.04
Sept. 21	329,417	41	6.24	3	.47	44	6.76
Sept. 28	328,994	148	22.88	25	3.90	173	27.04
Oct. 5	336,073	179	27.56	15	2.28	194	29.64
Oct. 12	342,017	159	23.92	7	1.04	166	24.96
Oct. 19	354,735	165	23.92	2	.29	167	24.44
Oct. 26	359,985	103	14.56	8	1.14	111	15.60
Nov. 2	370,485	73	9.88	------	------	73	7.88
Nov. 9	377,892	32	4.42	1	.13	33	4.52
Nov. 16	379,231	24	3.27	2	.27	26	3.54
Nov. 23	380,820	17	2.28	------	------	17	2.28
Nov. 30	379,909	10	1.35	1	.13	11	1.45
Dec. 7	378,347	6	.78	2	.27	8	1.09
Dec. 14	385,539	9	1.19	3	.40	12	1.61
Dec. 21	380,687	9	1.19	3	.40	12	1.61
Dec. 28	385,573	9	1.19	2	.26	11	1.45
Dec. 29-31	395,217	4	1.22	1	.30	5	1.46
Total	309,974	1,006	3.24	263	.78	1,269	4.09

--2449--

TABLE NO. 14--United States Navy enlisted personnel: Specific admission rates per 1,000 living, for influenza by months according to age groups, Sept. 1 to Dec. 31, 1918.

Age group.	Comp- lement	September.		October.		November.		December.		Total.
Age group.	Comp- lement	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.
15-19	138,666	6,649	47.94	3,973	28.65	906	6.46	746	5.37	12,274	88.51
20-24	214,880	22,676	105.52	15,290	71.10	2,873	13.37	2,700	12.56	43,539	202.62
25-29	82,574	7,656	92.59	5,907	71.53	1,161	14.06	1,023	12.38	15,747	190.70
30-34	24,858	1,859	74.78	1,634	65.73	342	13.75	275	11.06	4,110	165.33
35-39	7,700	220	28.57	228	29.61	53	6.88	60	7.79	561	72.85
40-44	3,422	84	24.54	81	23.67	25	7.30	25	7.30	215	62.82
45-49	1,477	29	19.63	45	30.46	11	7.44	20	13.54	105	7.19
50-54	749	15	20.02	13	17.35	3	4.00	7	9.34	38	50.73
55-59	287	3	10.45	6	20.90	2	6.96	6	20.90	17	59.23
60-64	137	3	21.89	3	21.89	------	------	------	------	6	43.06
65-69	19	3	157.36	------	------	------	------	------	------	3	157.89
70-74	21	------	------	------	------	------	------	------	------	------	------
75-79	10	------	------	------	------	------	------	------	------	------	------
Total	474,800	39,197	8.41	27,180	57.24	5,376	11.32	4,862	10.24	76,615	161.36

TABLE NO. 15--United States Navy enlisted personnel: Specific admission rates per 1,000 living, for pneumonia (all forms) by months according to age groups, Sept. 1 to Dec. 31, 1918.

Age group.	Comp- lement	September.		October.		November.		December.		Total.
Age group.	Comp- lement	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.
15-19	138,666	524	3.77	436	3.14	69	0.49	73	0.52	1,102	7.87
20-24	214,880	1,952	9.08	1,792	8.33	220	1.02	226	1.05	4,190	19.49
25-29	82,574	777	9.40	792	9.59	121	1.46	84	1.01	1,774	21.48
30-34	24,858	165	6.63	222	8.93	31	1.24	27	1.08	445	17.90
35-39	7,700	22	2.84	28	3.63	8	1.03	4	.51	62	8.05
40-44	3,422	11	3.21	3	.87	------	------	2	.58	16	4.67
45-49	1,477	2	1.35	------	1	.67	------	------	3	8.80
50-54	749	1	1.33	------	------	------	------	------	------	1	1.33
55-59	287	------	------	2	6.96	------	------	------	------	2	6.96
60-64	137	------	------	------	------	------	------	------	------	------	------
65-69	19	------	------	------	------	------	------	------	------	------	------
70-74	21	------	------	------	------	------	------	------	------	------	------
75-79	10	------	------	------	------	------	------	------	------	------	------
Total	474,800	3,454	7.27	3,275	6.89	450	.94	416	.87	7,595	15.99

TABLE NO. 16--United States Navy enlisted personnel: Specific death rates per 1,000 living, for influenza, including influenzal pneumonia, by months according to age groups, Sept. 1 to Dec. 31, 1918.

Age group.	Comp- lement	September.		October.		November.		December.		Total.
Age group.	Comp- lement	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.
15-19	138,666	175	1.26	212	1.52	24	0.17	17	0.12	428	3.08
20-24	214,880	774	3.60	941	4.37	94	.43	74	.34	1,883	8.76
25-29	82,574	336	4.06	472	5.71	59	.71	35	.42	902	10.92
30-34	24,858	93	3.74	136	5.47	13	.52	13	.52	255	10.25
35-39	7,700	10	1.29	15	1.94	4	.51	4	.51	33	4.28
40-44	3,422	3	.87	------	------	------	------	------	------	3	.87
45-49	1,477	2	1.35	2	1.35	------	------	------	------	4	2.70
50-54	749	------	------	------	------	1	1.33	------	------	1	1.33
55-59	287	------	------	1	3.48	------	------	------	------	1	3.48
60-64	137	------	------	------	------	------	------	------	------	------	------
65-69	19	------	------	------	------	------	------	------	------	------	------
70-74	21	------	------	------	------	------	------	------	------	------	------
75-79	10	------	------	------	------	------	------	------	------	------	------
Total	474,800	1,393	2.93	1,779	3.77	195	.41	143	.30	3,510	7.39

--2450--

TABLE NO. 17--United States Navy enlisted personnel: Specific death rates per 1,000 living, for pneumonia (all forms other than influenzal pneumonia) by months according to age groups, Sept. 1 to Dec. 31, 1918.

Age group.	Comp- lement	September.		October.		November.		December.		Total.
Age group.	Comp- lement	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.	Admis- sions	Rate.
15-19	138,666	7	0.05	11	0.07	1	0.007	3	0.02	22	0.15
20-24	214,880	47	.21	40	.18	6	.02	17	.02	110	.51
25-29	82,574	28	.33	10	.12	------	------	3	.09	46	.55
30-34	24,858	4	.16	13	.52	1	.04	2	.08	20	.80
35-39	7,700	3	.38	2	.25	1	.04	2	.08	20	.80
40-44	3,422	2	.58	------	------	------	------	------	------	2	.58
45-49	1,477	1	.67	1	.67	------	------	------	------	2	1.35
50-54	749	------	------	------	------	------	------	------	------	------	------
55-59	287	------	------	------	------	------	------	------	------	------	------
60-64	137	------	------	------	------	------	------	------	------	------	------
65-69	19	------	------	------	------	------	------	------	------	------	------
70-74	21	------	------	------	------	------	------	------	------	------	------
75-79	10	------	------	------	------	------	------	------	------	------	------
Total	474,800	92	.19	77	.16	8	.016	30	.063	207	.43

TABLE NO. 18--Case-fatality rates for influenza including influenzal pneumonia and pneumonia (all forms other than influenzal pneumonia) according to age groups, enlisted personnel of the Navy, by months, Sept. 1 to Dec. 31, 1918.

Age group.	Influenza, deaths per 100 cases.					Pneumonia (all forms), deaths per 100 cases.
Age group.	Sept.	Oct.	Nov.	Dec.	Entire quarter.	Sept.	Oct.	Nov.	Dec.	Entire quarter.
15-19	2.63	5.33	2.64	2.27	3.48	1.33	2.52	1.44	4.10	1.99
20-24	3.41	6.15	3.27	2.74	4.32	2.40	2.57	2.72	7.52	2.62
25-29	4.38	7.99	5.08	3.42	5.72	3.60	1.26	------	9.52	2.59
30-34	5.00	8.32	3.80	4.72	6.20	2.42	5.85	3.22	7.40	4.49
35-39	4.54	6.57	7.54	6.66	5.88	13.63	7.14	------	------	8.06
40-44	3.57	------	------	------	1.39	18.18	------	------	------	12.50
45-49	6.89	4.44	------	------	3.80	50.00	------	------	------	66.66
50-54	------	------	33.33	------	2.63	------	------	------	------	------
55-59	------	16.66	------	------	5.88	------	------	------	------	------
60-64	------	------	------	------	------	------	------	------	------	------
65-69	------	------	------	------	------	------	------	------	------	------
70-74	------	------	------	------	------	------	------	------	------	------
75-79	------	------	------	------	------	------	------	------	------	------

Severity of Influenza During the Autumn Epidemics.

While influenza manifested itself in all degrees of severity from the very mild to the overwhelming types of infection wherever epidemics occurred in the Navy during the autumn of 1918, the outstanding feature everywhere, ashore and afloat, was the frequency with which pneumonia of extremely virulent type complicated the disease. Competent pathologists in various parts of the United States have agreed that the pulmonary lesions did not conform to any of the well recognized types of pneumonia.

Different observers in the Navy have reported that it was difficult or impossible at times to say whether pneumonia was present or not during life and it was impossible in many instances to obtain accurate

--2451--

figures relative to the percentages of cases complicated with pneumonia. For this reason, in many instances, only approximately correct case-fatality rates could be determined for pneumonia.

Pneumonia as a complication of influenza at various stations.-- The percentages of influenza cases complicated by pneumonia and case-fatality rates for influenzal pneumonia at various stations are shown in the following table. The figures relate to all cases of influenza occurring at each station, including those transferred to hospital.

Station.	Complement.	Percentage of influenza cases complicated by pneumonia.	Case-fatality rate for influenzal pneumonia.
Training station, Newport, R.I.	9,493	18.0	26.0
Training camp, Pelham Bay Park, N.Y.:
Primary epidemic, September-October	14,220	18.0	26.0
Recurrent epidemic, December	14,220	17.5	25.0
Training station, Hampton Roads, Va.	11,104	12.2	33.5
Receiving ship, Norfolk, Va.	7,994	15.3	39.18
Training camp, Charleston, S.C.	4,167	5.6	29.0
Marine barracks, Parris Island, S.C.	10,424	21.0	15.0
Training camp, Gulfport, Miss.	1,772	11.4	19.04
Training station, Great Lakes, Ill.	44,605	18.19	48.0
Navy Yard, Mare Island, Cal.	7,657	14.3	24.8
Fifth naval district	------	13.16	35.8
U.S.S. Pittsburgh	------	11.0	50.9

Pneumonia as a complication of influenza in hospital cases.--The percentages of pneumonic complications among influenza cases transferred to hospital and case-fatality rates for pneumonia in such cases varied considerably, as shown in the following table:

Hospital.	Percentage of influenza cases complicated by pneumonia.	Case- fatality rate for influenzal pneumonia.
Naval hospital No. 5, Brest, France:
Among patients received from organizations in France	------	38.0
Among patients received from transports	------	48.0
Naval hospital, Cape May, N.J.	55.0	24.0
Naval hospital, Key West, Fla.	22.5	16.3
Naval hospital, Norfolk, Va.	30.0	28.6
Naval hospital, Pensacola, Fla.	8.2	27.2
Naval hospital, Philadelphia, Pa.	24.4	47.5
Naval hospital, Portsmouth, N.H.	38.2	32.3
Naval hospital, Washington, D.C.	27.4	19.7

Epidemiological study of influenza for an entire naval district.--Influenza statistics vary considerably for the different individual stations within a naval district. The following analysis of data from the third naval district illustrates this:

--2452--

Principal stations, third naval district.	Station comple- ment.	Cases, influenza.	Deaths, influenza and pneumonia.	Case incidence (per cent).	Case- fatality rate (per cent).	Epidemic death rate per 1,000 influenza and pneumonia.
Air station, Bayshore, N.Y.	880	97	6	11.02	6.18	6.81
Air station, Montauk, N.Y.	270	2	1	.74	50.00	3.70
Air station, Rockaway, N.Y.	843	80	6	9.49	7.50	7.11
Ammunition depot, Iona Island, N.Y.	385	53	1	13.25	1.88	2.59
Armed draft detail, New York	2,750	554	21	20.14	3.80	7.63
District section headquarters, Bath Beach, N.Y.	1,260	310	5	24.60	1.61	3.96
District section headquarters, New Haven, Conn.	436	171	3	39.20	1.75	6.88
Federal rendezvous, Brooklyn, N.Y.	1,700	172	7	10.11	4.07	4.11
Receiving ship at New York	5,800	1,049	48	18.08	4.57	8.27
Rifle range, Caldwell, N.J.	752	165	6	21.86	3.64	7.97
Rifle range, Peekskill, N.Y.	750	215	7	28.66	3.25	9.33
Pelham training camp, New York	15,316	2,616	134	17.08	5.12	8.74
Officer material school, Pelham Bay Park, N.Y.	1,111	69	4	6.21	5.80	3.60
U.S.S. Granite State, New York	566	175	2	30.92	1.14	3.53
Totals and averages	32,819	5,728	249	17.45	4.35	7.58

New York City:
Age 15-25--Males and females	1,240,510	------	3,657	------	------	2.94
Age 25-45--Males and females	1,987,700	------	9,999	------	------	5.03

It is to be noted that low case-fatality rates usually coincide with high case-incidence rates and it might be inferred that some stations reported more mild cases of influenza than others. The large and busy stations reported lower case-incidence rates and higher case-fatality rates than the smaller stations. The epidemic death rates for the various stations show greater uniformity.

Outbreaks of influenza presumably occurred simultaneously among civilians and naval personnel in and about greater New Yorik but, whereas the periods of greatest prevalence had passed in some of the naval stations before October 9, the crest of the epidemic in New York City was not reached until October 26. Among those of the naval personnel quartered outside of naval stations or living under conditions which were essentially civilian the incidence followed that of the civil community. This was particularly the case among the personnel of the steam engineering school, Hoboken, N.J., in the navy yard and among the force attached to district headquarters or employed in various offices.

It is not surprising that the epidemic should have run its course in congested stations more rapidly than among civilians. The epidemic reached its peak in the receiving ship September 21 and in City Park Barracks, October 1. These were the two most congested stations. With regard to preventive measures, quarantine was not imposed nor was the general use of masks or prophylactic sprays advised. Stations remote from cities were advised to prohibit city liberty, but stations in New York were advised by the medical aid to the commandant of the district to relieve congested barracks by freely granting liberty. Special preventive measures, which varied greatly in character, were instituted at different stations upon the initiative of the various medical officers.

At the three air stations gauze masks were worn. It will be noted that the epidemic death rates were moderately high at two of them

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and low at the United States Naval Air Station, Montauk. An epidemic of influenza occurred at that station in March, 1918, when 48 cases developed during a period of 12 days among the crew, then numbering 119. However, considerable change in personnel had taken place in the meantime, only 20 of those were actually attacked in March remaining.

At the receiving ship in New York, in City Park Barracks, at the Federal rendezvous, and at Bath Beach, all of which stations are in New York City, no restrictions were imposed on liberty; masks were not worn and no other personal prophylactic measures were undertaken. At the United States Naval Training Camp, Pelham Bay Park, liberty was restricted and visitors were excluded. This was also the rule on board the Granite State.

Some of the vagaries of epidemics become apparent when the case incidence and case-fatality rates of the training camp in Pelham Bay Park are compared with those of the Federal rendezvous. The former, located at the extreme edge of the city limits, had its men billeted in many rooms of moderate size and imposed a modified quarantine. At the latter, all men were quartered in one very large room and no restriction was imposed on liberty. The building is an armory located in a thickly populated section of Brooklyn. Pelham suffered more than the Federal rendezvous or the station at bath Beach. It is difficult also to explain the differences in rates at Peekskill and Iona Island. These stations are located opposite each other on the Hudson River, 40 miles above New York. The same restrictions were imposed on liberty at both, and presumably each had about the same amount of communication with the city, but they gave respectively the highest and lowest epidemic death rates. One hundred men of the United States Naval Aviation Detail, Keyport, N.J., escaped without a case, although the neighboring city suffered.

Epidemiological studies among personnel of the Navy Department, Washington, D.C.--The figures for the personnel on duty at the Navy Department, Washington, D.C., furnish a means of judging the effects of epidemic influenza among adults living under civilian conditions.

Bureau.	Comple- ment.	Number of cases.	Number of deaths.	Case incidence (per cent).	Case- fatality rate.	Death rate per 1,000 for epidemic.
Ordnance	303	37	1	12.2	2.70	3.30
Construction and repair	608	90	2	14.3	2.22	3.28
Steam Engineering	583	89	2	15.2	2.24	3.43
Navigation	1,351	431	5	31.9	1.16	3.70
Secretary's office Chief clerk's office	98	11	0	11.2	------	------
Yards and Docks	635	128	2	20.1	1.48	3.14
Compensation Board	41	4	0	9.7	------	------
Judge Advocate's office	46	7	0	15.2	------	------
Solicitor's office	35	5	0	14.2	------	------
General Board	13	3	0	23.0	------	------
Supplies and Accounts	1,699	388	8	22.8	2.06	4.70
Medicine and Surgery	150	35	0	23.3	------	------
Marine offices (annex and Corcoran Courts)	566	78	0	13.8	------	------
Hydrographic offices	163	26	1	15.9	3.84	6.13
Operations (including O.N.I. inspections and survey)	1,170	243	2	20.8	.082	1.70
Total	7,461	1,575	23	21.0	1.46	3.08
Washington, D.C.	¹500,000	25,729	²1,658	------	------	3.03

¹ Estimated. ² From Sept. 21 to Nov. 15, 1918.

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As far as the Navy Department was concerned it may be said that the epidemic ended about November 4, although sporadic cases continued to occur. The case-incidence rate, 21 per cent, coincides very closely with that which appears to have prevailed among civilians in various urban communities where morbidity reports were more or less satisfactory and complete.

Overcrowding in offices appears to have been a factor in the spread of the disease among the Navy Department personnel. The case-incidence rate was higher in overcrowded rooms and offices than in those more evenly proportioned. That the rates were not higher under the conditions of overcrowding, which then existed, was in a measure due to the favorable weather prevailing which made it possible to keep all windows open and utilize all means of ventilation. Of course, all preventive measures that were practicable were put into effect, and a sanitation officer made daily visits to all offices for the purpose of survey and to give practical advice. Not only was more complete sanitary supervision exercised but it is fair to say that those who became ill were able to secure medical advice and care more promptly and more regularly than persons under similar circumstances in civil employment in most of the large cities of the country. It should be stated that a great majority of the persons represented by these dat belonged to the age group 20-30, the age group which practically everywhere showed very high incidence rates for influenza and the highest case-fatality rates.

True case-fatality rates for influenza and influenzal pneumonia, entire Navy.--From August 31 to December 31, 1918, there were reported for the entire Navy 91,656 cases of influenza, 6,425 cases of bronchitis, and 8.816 cases of pneumonia (all forms).

The great majority of all cases of pneumonia in the Navy during this period were influenzal in origin and, if it be assumed that all cases were influenzal, these figures would indicate that 9.6 per cent of the cases of influenza were complicated with pneumonia, of no cases diagnosed as acute bronchitis are included, and 8.9 per cent if the 6,425 cases of bronchitis are included. Furthermore, the case-fatality rate for pneumonia as indicated by these figures would be 49.67 per cent. This is obviously much higher than the true rate, but the true rate can not be determined accurately. There is no doubt about the deaths, but it is known that many cases of pneumonia terminating in recovery were not recognized, and in some cases of influenza which resulted in recovery the diagnosis was not changed to pneumonia even though clinical findings suggested or indicated pulmonic complications. In other words, many nonfatal cases of pneumonia were not reported as pneumonia. Every certificate of death received in the bureau was edited by the Division of Preventive Medicine, and in every case of pneumonia where an influenzal origin was indicated or suggested in the history of the case as contained in the body of the report, the death was charged to "influenzal pneumonia."

During the period, August 31, to December 31, 1918, 4,136 deaths from influenza and influenzal pneumonia occurred in the Navy, and the mean strength was 569.470, making the death rate from influenza 7.26 per 1,000, and the case-fatality rate for influenza 4.5 per cent. The latter rate is undoubtedly higher than the true rate because many mild cases of influenza, and sometimes cases of moderate severity, were not admitted to the sick list. It has been estimated at various

--2455--

stations that for every 100 cases of influenza formally admitted to the sick list, from 50 to 75 mild cases were never recorded. With 50 per cent added to the number of recorded cases of influenza the indicated case-fatality rate becomes 3.0 per cent. This figure more closely approximates the true case-fatality rate than 4.5 per cent. In all probability the true case-fatality rate for influenza in the Navy was between 2.5 and 3.5 per cent.

It is more difficult to reach a conclusion with regard to the case-fatality rate for influenzal pneumonia. The figures given above would indicate that pneumonia was a complication in 9.6 per cent of the cases of influenza. This figure is too low but there are no means of accurately determining the true percentage. At various stations where careful study was possible the figures varied from 11.4 to 21 per cent, giving an average of 15.9 per cent and a median figure of 16.25 per cent. Assuming that approximately 15 per cent of recorded cases of influenza in the navy were complicated with pneumonia the indicated case-fatality rate for influenzal pneumonia during the period August 31 to December 31, 1918, would be 30 per cent, or, assuming that all deaths from pneumonia during this period were really due to influenza, 31.8 per cent.

Recognition of Influenza

Influenza is not easily differentiated from other acute respiratory infections when the disease is not epidemic, and for this reason in studying influenza, distinctions must not be drawn too finely between the types of cases occurring during epidemics, and the types reported as influenza before and after epidemics. A sudden onset with malaise and weakness, leading in a few hours to prostration out of proportion to the other clinical manifestations; the prominence of headache, particularly the so-called post-orbital headache; muscular pains, sharp rise in temperature to 101 or 102 degrees of even higher, and leukopenia, appear to be the principal guides to recognition of the true case of influenza, pending agreement as to the value of bacteriological findings or the discovery of a microöganism which can be agreed upon as the causative agent of the disease.

Studies of cases occurring in various outbreaks of influenza in the Navy during this pandemic show a remarkable similarity in the clinical characteristics of the disease all over the world. Inasmuch as epidemics varied considerably in duration and intensity it is not surprising that there was also considerable variation in the proportion of uncomplicated cases, both mild and severe, to the complicated severe cases. Mild, uncomplicated cases occurred everywhere, even when epidemics were at their peaks, and such cases appear to have had the same characteristics wherever they occurred, before, during, and after the primary epidemic. At the majority of naval stations, as well as on board ship, a certain number of cases occurred which were clinically very severe from the moment of onset and terminated fatally, sometimes in less than 36 hours. These cases occurred principally at the height of an epidemic; were uncommon previous to September 1, 1918, and were not often seen after the passing of the primary epidemic.

The outstanding feature of the pandemic was the frequency with which secondary pneumonia of the bronchial type developed. This

--2456--

complication was the cause of death in practically all fatal cases of influenza.

The clinical course in cases complicated by pneumonia varied considerably at each place or hospital. Pneumonia developed early, almost immediately in some cases; in others only after several days of influenza or after a remission, and in some instances after convalescence had apparently begun.

With due allowance for the fact that a hemolytic streptococcus was associated with most or all cases of complicating pneumonia in one place, whereas a pneumococcus predominated in another place, it may be said that there was a remarkable similarity in the cases complicated with pneumonia as well as in ordinary uncomplicated cases of influenza wherever they occurred, not only in all parts of the United States but in England, France, the West Indies, South America, and the Orient. That is, the general picture of influenzal pneumonia was the same all over the world.

In practically all cases of complicating pneumonia a hemolytic streptococcus, a pneumococcus, the Pfeiffer bacillus, or a combination of these microörganisms seemed to play a part in causing the pneumonic lesions. However, it is generally agreed that the pneumonia cases were sufficiently characteristic to stand out as a type different from cases of ordinary pneumonia seen in recent years and more or less different too from the types of broncho-pneumonia which so frequently complicated measles in 1917 and early in 1918.

From various reports, with reference to clinical and post-mortem findings and with regard to statistical data for various stations and ships in many parts of the world, it appears that of 1,000 cases of influenza from 30 to 40 terminated fatally; from 10 to 30 in some places and as many as 90 or more under unusual circumstances. As a rule, from 100 to 200 cases in a thousand had pneumonia complications with definite clinical manifestations. Such cases averaged, perhaps, 150 per 1,000 cases of influenza. A small number of these patients lived only a day or two, and the exact nature of the infection microörganisms and the immunological conditions involved in such cases are still unknown In many of the fatal cases of pneumonia a secondary invader, a pneumonococcus or streptococcus, or both, seemed to play an important if not the paramount rôle in causing death. In some cases the Pfeiffer bacillus was present in the tissues and in cells in great numbers and appeared to be responsible for the pneumonia, inasmuch as it was recovered in pure culture.

The causes of death other than pneumonia were few. Cerebrospinal fever was a not uncommon concomitant infection or sequela at several training stations and in a few ships.

Besides broncho-pneumonia, the following complications were noted:

--2457--

During the calendar year, 1918, the cause of death in 4,155 fatal cases of influenza was assigned as follows:

Influenza (uncomplicated or complication unrecognized)	931
Pneumonia, bronchial	2,432
Pneumonia, lobar	730
Abscess of kidney	1
Acute dilation of the heart	2
Pulmonary edema	1
Embolism	1
Meningitis, cerebro-spinal	25
Acute nephritis	5
Pleurisy, serofibrinous	2
Pleurisy, suppurative	17
Sinusitis	1
Septicemia	5
Hydropneumothorax	1
Erysipelas	1
Total	4,155

Of the cases of influenza in which complications did not develop--800 to 875 in a thousand, and probably more than 900 is some instances if the truth could be known--the majority were ordinary cases of influenza, similar to the grippe cases of ordinary times. In some of the uncomplicated cases the patient appeared to be very ill for three or four days. On the other hand, there were always numerous mild attacks which either did not prevent the performance of usual tasks or necessitated confinement to bed or quarters for only one, two, or three days. The frequency with which very mild cases were seen leads to the belief that a great many persons were attacked by the disease in such mild form that it was not recognized even as an acute minor respiratory affection.

It is not improbable that approximately 40 per cent of the total naval personnel actually became infected at some time or other in 1918, which would correspond to the figure accepted for the incidence in civilian populations during the 1889-90 pandemic.

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Influenzal pneumonia.--Some of the cases were very similar in onset to acute lobar pneumonia, and a good many cases were so diagnosed, particularly early in the epidemic. In some instances even the post mortem findings simulated those of acute lobar pneumonia. The more thoroughly cases were studied the less did it appear that the lesions of influenzal pneumonia were ever those of a true lobar pneumonia.

In most cases the onset of pneumonia was not abrupt, and the pulmonary complication developed so unobtrusively that it was likely to be overlooked without careful and repeated physical examinations. Frequently the temperature, respiration rate, and character of the sputum suggested the presence of pneumonia when it could not be found with the stethoscope. A rising white count was also significant. In some instances the pneumonic complication developed within the first 24 hours, but in the great majority of cases not until after 48 hours, and frequently not until after a remission on the third of fourth day. Several observers noted that broncho-pneumonia of some degree could be considered to exist if there was not a cessation of influenza symptoms by the sixth day.

After full development, the distinguishing features of influenzal pneumonia were extreme toxicity, rapid respiration becoming very marked upon the least exertion, early appearance of cyanosis of the lips, ears and finger tips extending to the body before death; a frequent paucity of physical signs in comparison with the obviously critical condition of the patient, pulmonary edema, and abundant watery bloodstained sputum or thin rusty muco-purulent sputum. Of course, in many cases there were physical signs of extensive involvement of the lungs.

The appearance of the patient; his bluish or purplish lips, cyanosis of the ears, ashen cyanosis of the face or blue mixed with red when there was congestion, drooping eyelids, and the "air hunger" which often seemed due more to toxemia and to changes in the blood than to lack of proper aeration in the lungs, made an unforgettable picture in cases where medical treatment was practically without avail.

Many of the cases were regarded as mixed infections and clinically many were septicemias. In the majority of instances blood cultures were negative, but in some streptococci or pneumococci were obtained from the blood during life. Rarely, the Pfeiffer bacillus was found in blood culture.

Not all cases of influenzal pneumonia presented the picture described above. Indeed, reports from various naval hospitals denote considerable variation in clinical manifestations as well as in post-mortem findings at each place during the epidemic, but this was the picture in many of the cases, especially at the height of the epidemic when influenza seemed to be more highly communicable than before or after and when influenzal pneumonia was more prone to occur. It would not do to compare the pneumonia cases occurring at one place early in the epidemic with those occurring later at another place. Pleurisy of some degree complicated the great majority of pneumonia cases at all stages of the epidemic, but there were very few empyemas until after the epidemic had passed, even in patients living as long as 14 days.

--2459--

Physical signs in the chest varied extremely from those strongly suggestive of frank lobar pneumonia to a few subcrepitant rles only, elicited with difficultly, or no signs whatever. Collections of fluid, emphysematous areas, collapsed areas, extravasations, filled or obstructed small bronchi, confluent areas of consolidation, alterations of the blood and possibly acute toxic neuritis of the vagus and peripheral nerves of the thorax accounted for diverse physical findings. Frequently neither a diagnosis nor prognosis could be based upon physical findings.

Cases of fatal septicemia were reported in which there was no consolidation in the lungs, although there was intense congestion with extensive bronchitis. The bronchioles and alveoli were filled with a fluid resembling hemolyzed blood. Blood cultures in certain groups of such cases gave pure growths of a green-producing streptococcus which sometimes hemolyzed and sometimes did not. This microörganism also grew as a diplococcus at times and was difficult to distinguish from Type IV pneumococci.

Some observers reported cases of hemorrhagic septicemia without lung involvement other than hemorrhages or extravasations in which a pneumococcus was thought to be responsible. It is possible that this microörganism was really a streptococcus of the type just mentioned.

Morbid anatomy.--At the United States Naval Hospital, Chelsea, Mass., post-mortem study of 23 cases at the height of the epidemic which began in Boston August 27, 1918, showed the Pfeiffer bacillus present in the lungs in pure or mixed culture in 19 cases and in the other 4 a hemolytic streptococcus was present in pure culture. The Pfeiffer bacillus was present alone in 6 of the 23 cases. At the United States Naval Hospital, Philadelphia, lung punctures made in 31 cases during life showed the presence of the Pfeiffer bacillus, predominating or mixed with "strepto-pneumococcus," or with M. cararrhalis and other common microörganisms in 15 cases.

The post-mortem findings in the chest with respect to the amount and character of fluid found in the pleural cavities varied considerably. Pleuritis of some degree occurred in the great majority of all cases of influenzal pneumonia. Thoracentesis was frequently and repeatedly performed during life, necessarily affecting somewhat the amount of fluid found after death, which varied from a few cubic centimeters to a liter or more. In most cases the amount was small.

Reference has already been made to the fact that empyema was of very infrequent occurrence during the epidemic. However, it was found in 6 of 56 cases of influenzal pneumonia coming to necropsy at the United States Naval Hospital, Great Lakes, Ill. In most of the cases of fluid found in the pleural cavities was very thin. It was generally noted that the fluid contained little fibrin and was tinged with blood.

The lesions in the lungs were characteristically those of perio-bronchitis and broncho-pneumonia. When the lesions were limited to one lobe, usually a lower lobe was affected. In most cases areas of consolidation were found in both lungs, and the lesions were scattered through several lobes. In many instances confluent areas of consolidation gave the gross appearances of lobar pneumonia.

--2460--

A striking feature which characterized influenzal pneumonia was the great amount of thin, watery, bloody, or blood-colored fluid or very dark fluid containing hemolyzed blood which dripped from the cut surface of the lung, filled the alveoli and bronchioles, and in the form of extravasations under the visceral layer of the pleura in streaks or in areas of from one to several centimeters in diameter resembled bullae of suggested subpleural hemorrhage.

Many composite pictures were presented, but in general it appears that lung findings could be divided into two principal groups, depending chiefly upon whether death occurred in the first few days of the disease or whether life was prolonged for 10 days or more.

Where death occurred early in the disease the picture was that variously described as acute, hemorrhagic pneumonitis, disseminated hemorrhagic pneumonia, primary toxic injury of pulmonary tissue or rapidly fatal septicemia with intense engorgement and localizations in the lungs. The lungs were heavy. The pleural surfaces were smooth and usually wet, bluish gray, purple, or slate colored, and often showed a mottling or dark red streaks due to collections of hemorrhagic fluid or extravasations of fluid containing blood pigment beneath the pleura. The lung surfaces were usually almost completely free from fibrin. Here and there the lungs were partially collapsed. Various portions of the lungs, especially the lower lobes, showed areas of consolidation, and frequently edema and emphysema were noted in areas not consolidated.

The cut surface of the lung varied in color from bluish gray or grayish purple to dark red. As a rule, affected areas were dark red. Sanguineous red or dark fluid dripped from the cut section. "The coarse nodular consolidation of ordinary broncho-pneumonia was not present." Cases of longer duration frequently showed a greater variety of lesions. "The lungs exhibited a constantly varying picture of broncho-pneumonia from a peppering of discreet lobular areas well scattered throughout all lobes to large and often massive confluent areas of consolidation involving 75 per cent of the lungs." "The shades of color of the prominent lobules surrounded by the red of the unconsolidated areas and the pale collapsed areas gave a mosaic appearance." Areas of emphysema were usually present in uninvolved portions of the lungs as well as in tissue intervening between consolidated areas. Sometimes intense engorgement without real consolidation was found, and from areas filled with fluid and presenting a solidified appearance blood stained or dark fluid exuded upon pressure. The lining membrane of bronchioles was intensely congested and even the lining of the trachea and large bronchi was often deep red.

The relatively small amount of fibrin present in the lung of influenzal pneumonia was noted by most observers. Panbronchitis and peribronchitis were commonly found. The peribronchial and bronchial lymph glands were generally enlarged, intensely inflamed, and often edematous.

In cases of longer duration, coming to necropsy after 10 or more days of illness, more extensive and more complete consolidation was usually found and dilation of bronchioles, congested in the cases of short duration, showed extensive necrosis in the late cases and the bronchi frequently contained thin purulent material or pus.

--2461--

In some of the more prolonged cases diffuse and confluent small abscesses were noted with yellow pus exuding from the cut surface. Fibrino-purulent material was present in many of the late cases. In some instances bronchiectasis was extensive. In general, a prominent feature in the cases of 10 or more days' duration was extensive bronchitis and peribronchitis with foci of broncho-pneumonia in various states from grayish consolidation to abscesses containing creamy pus. In these cases the lungs were dryer but there were traces of previous engorgement. In many instances there were evidences of organization taking place in the alveoli and dilated bronchioles.

In cases coming to necropsy after 14 days of pneumonia inter-lobular fibrino-purulent pleural exudates were not uncommon.

"In sections studied microscopically from the early stage of pneumonia it is more evident than in gross that a general bronchitis and especially bronchiolitis precedes the infiltration of alveoli. One finds in unconsolidated areas, bronchioles filled with an exudate composed of polymorphonuclear and mononuclear leucocytes with varying amounts of fibrin and amorphous hyalin material. The infundibula and air vesicles subtended by the bronchiole may contain an exudate of leucocytes with little or no fibrin, forming a small focus of broncho-pneumonia. More characteristic of this stage of inflammation is a lesion of the walls of certain infundibula and air vesicles in the neighborhood of, and within the latest areas of consolidation. A hyalin membrane partially or completely covers the walls of these air spaces. The membrane is irregular in thickness, sometimes stratified with occasional cells within narrow clefts. It tends to be thickest over the angles of the wall, though it may be so abundant as to fill an alveolus.

"In older foci of pneumonia leucocytes are the predominant inflammatory element, with small amounts of blood and fibrin, but in the diffusely consolidated patches or lobes of short duration, serum, fibrin, and red cells are most conspicuous. Especially prominent are the large areas of hemorrhage from capillary rupture. In certain areas numerous focal necroses of alveolar walls are observed. In older lesions the smaller bronchi contained plugs of leucocytes, fibrin, and hyalin material, and their epithelial lining was partially or completely ulcerated and covered by a fibrino-purulent membrane."

Most of the victims in influenza in the Navy were robust young men when attacked and the numbers of these well-developed and well-nourished bodies at necropsy made a spectacle sad beyond description.

Extreme engorgement of the whole venous system with distension of subcutaneous and abdominal veins filled with a thin black fluid, watery in consistency, was sometimes noted. The right side of the heart was then acutely dilated. Frequently there was no marked alteration in the size of the heart. "The heart muscle commonly had a glazed or scalded appearance." It was noted at times that the pectoral and recti muscles presented the same appearance. Acute degenerative myocarditis was commonly found. Reports made little reference to the condition of the cardiac valves. Acute vegetative endocarditis of the mitral valve was noted in one instance at the United States Naval Hospital, Great Lakes, Ill.

The spleen, liver, and kidneys, as a rule, exhibited varying degrees of congestion. Active acute nephritis was infrequently found. A

--2462--

report from the United States Naval Hospital, Great Lakes, Ill., stated that little or nothing worthy of special note was found in organs other than the lungs in the acute pneumonia cases. Complications were found in cases where death occurred later on, after the primary acute attack had subsided. The spleen was seldom enlarged to any marked degree. It was usually firm. The list of complications given above indicates the character of lesions found in these organs in unusual instances.

In a report from the United States Naval Hospital, Philadelphia, Pa., intense congestion of the adrenal bodies without progressive inflammatory changes was noted. A report from the United States Naval Hospital, Chelsea, Mass., noted small foci of hyalin necrosis in the adrenal bodies in a majority of the cases in which death occurred four or five days after the onset of pneumonia.

First and last, leptomeningitis was found in a good many instances. Sometimes a pneumococcus was recovered from the meninges; sometimes a streptococcus; and rarely, the Pfeiffer bacillus. As previously noted, brain abscesses were occasionally found. Edema of the brain was frequently noted.

Other findings noted in rare instances at post-mortem examination were hyalin degeneration, necrosis, rupture, and hemorrhage into one or both of the abdominal recti muscles, acute arteritis, phlebitis, and septic emboli with resulting infarction of the brain or of one or another of the parenchymatous organs.

Clinical Manifestations of Influenza and Influenzal Pneumonia
as Commented Upon in Various Navy Reports

Headache.--Reports generally agree that headache was one of the most constant symptoms in the early stages of influenza. It occurred as the most prominent symptom in from 75 to 80 per cent of 900 cases of influenza analyzed at the United States Naval Hospital, Philadelphia, Pa., and as the chief complaint in from 50 to 30 per cent of the cases according to whether they were admitted to hospital within the first 24 hours of the disease or not until after 72 hours.

Headache was usually frontal. In many reports it was designated as "post-orbital." The eye balls were frequently painful and tender on pressure. Undoubtedly due to the toxemia in some cases, headache was commonly caused by nasal congestion and rhinitis with blocking of the frontal sinuses.

Headache late in the disease was reported as due to a variety of lesions; inflammation of the frontal sinuses, less commonly other accessory sinuses, neuritis, meningitis, embolism, intracranial congestion and abscess.

Prostration.--Prostration of some degree almost from the moment of the sudden onset of influenza was rarely absent. In cases of ordinary severity the initial weakness was almost always out of proportion to the fever and to the pulse and physical findings in comparison with other acute infectious diseases. Even in very mild cases there was often great weakness which persisted throughout the convalescent period and fatigue was often readily induced long after the patient had returned to duty. Instances were very common where unusually strong, fully developed men perfectly well in the afternoon were so weak the following morning upon admission to hospital with influenza that they could scarcely sit up in chairs.

--2463--

Many patients became ill on the street while on liberty and had not sufficient strength to return to ship or station.

Prostration was commonly attributed to intense early toxemia which occurred suddenly and in complicated cases developed into a profound adynamic state in which myocarditis and toxic neuritis played a part.

Vertigo.--this was an unpleasant symptom frequently present even in mild cases. While brought on by slight exertion it also occurred frequently when the patient was lying quietly in bed.

Chills.--An initial chill was of very frequent occurrence. A definite chill or chilliness occurred in about 50 per cent of the cases. Chilly sensations commonly recurred during the first 24 hours of the disease and not infrequently chilliness recurred at irregular intervals up to 72 hours.

Muscular pains.--Reports from all ships and stations showed uniform agreement in making mention of the prominence of backache and pains of varying severity in other muscle groups and in the joints. A common description was, "The patient feels as though he had been beaten all over with a club." In the Philadelphia series, general muscular pains were noted as a prominent symptom in from 54 to 63 per cent of all cases admitted to hospital.

Coryza.--A "cold in the head" with sneezing and nasal discharge occurred in the early stages of the disease in perhaps half the cases of influenza. In the Philadelphia series this symptom was noted in 20 per cent of the cases admitted to hospital.

Conjunctivitis.--Some degree of congestion of the conjunctivae accompanied coryza. Congestion of the eyes was noted in from 25 to 30 per cent of the 900 hospital cases carefully studied in Philadelphia. Infrequently conjunctivitis of marked degree was noted and corneal ulcers occurred in several instances in a series of 2,924 cases of influenza studied at the United States Naval Hospital, Great Lakes, Ill.

Nausea and vomiting.--The so-called intestinal form of influenza was not common during this pandemic. Nausea occurred in from 10 to 20 per cent of the cases studied at the United States Naval Hospital, Philadelphia, and vomiting occurred in from 5 to 15 per cent. Nausea and vomiting were more common in cases admitted to hospital late in the disease.

In a few cases, perhaps a dozen, diarrhea was associated with nausea and vomiting. In the majority of these instances there was some abdominal distension and pain with tenderness on palpation, particularly in the right iliac fossa. The pain disappeared quickly, as a rule, but simulated appendicitis while it lasted.

A report from the United States Naval Hospital, Chelsea, Mass., noted that nausea and vomiting occurred in a few cases. At the United States Naval Hospital, Great Lakes, Ill., it was believed that nausea and vomiting in the majority of instances were due to overmedication, as these symptoms were relieved by discontinuing medication.

At the United States Navy Base Hospital No. 5, Brest, France, only one case of what might be termed a definite gastro-intestinal form of grippe with nausea and vomiting and severe diarrhea was noted. In a report from the receiving ship at Norfolk, Va., which included a detailed clinical description of 962 cases of influenza, no mention of

--2464--

nausea and vomiting was made, and it is significant that these symptoms were not alluded to in most reports. Diarrhea was not a prominent symptom. In most reports it was not mentioned.

Hematemesis.--Reports indicate that hematemesis occurred very infrequently. It was not mentioned in the report of 2,924 cases at the United States Naval Hospital, Great Lakes, Ill., and in the report from the United States Naval Hospital, Philadelphia, Pa., it is noted that when vomiting occurred the vomitus was usually free from blood. Hematemesis of large amount was not mentioned in any report.

Abdominal distension.--Paralysis of the intestine appears to have preceded death in the majority of fatal cases. Abdominal distension was prone to occur in toxic cases and was difficult to overcome.

Abdominal pain.--Abdominal pain and soreness in the region of the diaphragm were frequently attributed to continued coughing. In some instances degenerative changes in the abdominal muscles were productive of pain. Not infrequently pleuritic pain referred to the region of the gall bladder led to a diagnosis of acute cholecystitis or appendicitis. Occasionally acute cholecystitis did occur.

Hiccough.--Hiccough occurred in approximately 1 per cent of hospital cases. Occasionally it was serious and could not be controlled. Of approximately 3,000 cases of influenza treated in the naval hospital at great Lakes, persistent hiccough occurred in but one instance, the patient dying on the fifth day.

Icterus.--Jaundice occurred infrequently and it is mentioned in only a few reports. It was present, probably, in less than 1 per cent of the cases of influenza. Duodenitis and choledochitis appear to have been rare. Icterus of hematogenous origin occurred occasionally in severe cases and was attributed in a few instances to acute hepatitis. In one case at the United States Naval Hospital, Philadelphia, that of a negro, jaundice was so intense that the sputum was canary yellow in color. Jaundice of some degree was observed in a majority of the fatal cases in the naval hospital at Great Lakes. About 50 per cent of the Philadelphia cases having jaundice terminated fatally.

Nervous system.--In a large majority of influenza cases, even in mild cases, the nervous system was affected to some degree. Insomnia was mentioned in many reports. Somnolence was also frequently noted. Seventy per cent of the hospital cases treated at Great Lakes during the height of the epidemic there exhibited mental apathy. Active delirium occurred in 20 per cent of the cases. Occasionally delirium was active to a maniacal degree. Stupor and lethargy were noted in some instances. Perception was frequently dulled, and often in complicated cases the patient did not realize his serious condition. "Lethargic or mildly stuporous patients with extensive broncho-pneumonia, obviously critically ill and within 24 to 48 hours of death, nevertheless stated that they felt well and requested permission to leave bed and return to duty." On the other hand, marked mental depression was not uncommon in uncomplicated cases of moderate severity and was sometimes associated with a fixed idea that death must follow.

Several observers described cases exhibiting meningeal symptoms; severe headache, stiffness of the neck or retraction of the head and positive Kernig sign with delirium, in which the cerebro-spinal fluid

--2465--

was clear. Sometimes lumbar puncture and withdrawal of clear fluid under pressure resulted in prompt alleviation of symptoms.

A mild degree of toxic neuritis of peripheral nerves was not uncommon. Among the sensory phenomena, hyperesthesia, pains in the arms and legs, tingling, itching, heat sensations, and other indications of paresthesia were noted. Sometimes anesthesia followed hyperesthesia. Pain along nerve trunks, notably of the sciatic or median nerve, was complained of in some instances. Various motor nerves were also affected. Some of the fatalities were in part attributed to toxic neuritis of the vagus nerve.

Mental depression not infrequently continued or developed during convalescence from influenza. In the Philadelphia series some post influenzal psychoses were seen. The cases were described as having mild melancholia or suicidal tendencies. One patient had a series of epileptiform convulsions, preceded and followed by melancholia with depressive delusions, from which he ultimately recovered.

Many patients developed neurasthenia during convalescence. Mental depression and loss of interest in the surroundings were noted, and in a number of cases a diagnosis of dementia praecox was made. Recovery usually followed in from 6 to 8 weeks.

Partial paralysis of the palate, ptosis, strabismus, and weakness of various muscles were frequent sequelae even in mild cases of influenza. Impairment of hearing was also observed. Such disabilities usually wore off in the course of a few months.

Temperature, pulse, and respiration.--Many reports agree in the statement that the onset of fever was abrupt. As a rule, the temperature rose rapidly to between 101 and 105 F., and remained high in nearly all cases until a remission occurred on the second, third, or fourth day. In uncomplicated cases the remission usually marked the beginning of convalescence although some cases terminated by lysis, and occasionally a subsequent rise of short duration occurred. A subsequent rise in temperature generally indicated a pulmonary complication, and when the temperature remained high after the sixth day many observers learned by experience to suspect the presence of broncho-pneumonia. In cases of influenzal pneumonia high temperature was the rule--from 104 to 105 F., and frequently higher at certain hours of the day. At the United States Naval Hospital, Puget Sound, Wash., a temperature of 107 F. was observed in one case.

The usual observation was that the pulse was not unduly rapid. Even in pneumonia the rhythm remained regular although it was often momentarily disturbed during a paroxysm of coughing. The pulse was usually soft and the volume large. Frequent mention was made of a poor quality of heart sound at the apex and of muscular impairment. However, cardiac failure per se was not often the immediate cause of death. Many cases were seen in which the apex beat was forcible on palpation and the heart sounds loud and yet the patient was pulseless at the wrist and death was approaching.

Low blood pressure was reported as frequent or constant. The systolic pressure usually ranged from 85 to 110. The diastolic pressure was frequently between 45 and 55. The pulse pressure was often increased.

Many reports indicate that the pulse rate was slow in proportion to the temperature. A pulse of 80 with a temperature of 104° or a

--2466--

pulse of 90 with a temperature of 105° and a respiration rate of 19 or 20 were commonly noted. Exceptionally a very rapid pulse was noted in pneumonia cases. In a few instances bradycardia was observed. A rapid pulse was not uncommon during convalescence from influenza, especially after exertion.

The respiration rate in influenzal pneumonia was not increased to the degree that would be expected from the nature of the lesions in the lungs. The rate was usually below 30. "Whenever the respirations exceeded 24 per minute, pneumonia was suspected, and this suspicion was strengthened if the sputum was bloodstained, excepting when pleuritis caused the increased respiratory rate." Breathing was free but shallow and frequently became very rapid upon exertion. In such cases the form of cyanosis alluded to above appeared to be due, in part at least, to changes in the constituents of the blood leading to air hunger without causing great distress in breathing. With the development of pulmonary edema cyanosis increased, dyspnea became marked, the breathing was rapid, the patient was delirious, and there was great restlessness. "This distressing terminal stage, with the bubbling rles, frothy sputum, the too vivid picture of heaving chest, cyanosis, and air-hunger facies, will remain as a nightmare of those of us who dealt with these cases in large numbers."

Cough.--Cough was a very constant sign and ranked next after headache in occurrence during the first 48 hours of the disease. There were few cases in which cough did not occur at some stage of the disease. It occurred in from 80 to 85 per cent of all cases of influenza.

Of 352 cases of influenza admitted to the United States Naval Hospital, Philadelphia, Pa., within 24 hours after the onset of the disease, cough was present in 67 per cent and was the chief complaint in 8.5 per cent of the cases thus early in the disease.

Moderate in severity, "dry" or "hacking" at first, and usually accompanied by "tightness" or "soreness" in the chest, the cough loosened rather promptly as a rule and the sputum became abundant. Statements with regard to cough varied considerably in different reports. "Frequently, on the second or third day, patients complained of 'tightness' or 'soreness' of the chest, and there appeared a bronchial cough, moderate in severity, which was productive of large amounts of greenish or whitish mucoid sputum." "Cough developed early in most cases, with definite pain in the chest." The larynx was frequently involved in the course of influenza with resulting laryngeal cough and aphonia. This condition rarely lasted more than a week, and often there seemed to be very little discomfort from that source. During epidemics many persons who did not become acutely ill developed laryngeal or bronchial cough which persisted for several weeks. Few patients actually ill with influenza escaped bronchitis of some degree, and even in mild cases cough was sometimes very distressing and persistent during convalescence. "This persistence of mild bronchitis, with little cough and little or no sputum, should make one careful not to discharge men too early to duty where exposure may precipitate another attack."

With the development of influenzal pneumonia the character of the cough was modified by the nature and extent of the lesions in the lungs and the degree of pleural involvement. Some of the pneumonia patients had very little cough in proportion to the physical

--2467--

findings. When sputum was raised with difficulty the cough was frequently most distressing, paroxysmal in character, and interfered with sleep. When the sputum was abundant it was generally evacuated without difficulty until the patient became too weak to cough effectively, when even with the lungs full there was sometimes no coughing at all.

Sputum.--In uncomplicated cases of influenza the sputum was mucoid at first and later muco-purulent and rather thin, grayish or greenish in color. The amount varied considerably but it was usually moderately abundant after the first two or three days. In exceptional cases there was little or no sputum. In some apparently uncomplicated cases the sputum was rusty or tinged with blood.

In cases of influenzal pneumonia the character of the sputum varied from a thin, watery, bloody fluid resembling diluted red paint, to bloody pus and in later cases and cases of prolonged duration pur greenish or yellowish pus. Destruction of erythrocytes and admixture of free blood pigment with the sputum led to a variety of colors; red, rusty, dark brown, and even black. In some cases the bronchi were filled with fluid; in others the sputum was scanty, but in most cases all through the disease the amount of sputum was more abundant than in ordinary cases of pneumonia. The sputum was frequently recorded as frothy. The more purulent the less froth it contained, as a rule. In the terminal stage with pulmonary edema froth was commonly noted.

Hemoptysis.--As noted above, blood or blood coloring matter in the sputum was of very common occurrence. Actual hemorrhage into the lungs and into the bronchi occurred not infrequently in the pneumonia cases. Undoubtedly hemoptysis was due in many instances to the escape of blood from the intensely congested bronchial mucous membrane. At the United States Naval Hospital, Great Lakes, Ill., it was noted that hemoptysis frequently preceded the development of pneumonia and sometimes continued throughout. All degrees from bloody froth to frank hemorrhage were observed. In reports reaching the bureau no mention was made of fatal pulmonary hemorrhage or of an instance in which death could be attributed to the loss of blood rather than to infection and toxemia.

Epistaxis.--Hemorrhage from the nose was quite commonly associated with influenza in uncomplicated cases as well as with influenzal pneumonia. In Philadelphia, epistaxis occurred in 9.7 per cent of the 900 cases treated in hospital, and in one instance it was necessary to resort to packing and intramuscular injection of serum. Bleeding was frequently due to venous engorgement without evidence of inflammation. The blood seemed to ooze from the mucous membrane and usually no ulceration could be detected. On board the U.S.S. Leviathan epistaxis was observed in 20 per cent of the cases as a very early manifestation of influenza. In the receiving ship at Norfolk, Va., epistaxis was troublesome in 6.2 per cent of the 962 cases of influenza, and it was noted that in every case with intense headache the headache was greatly relieved with bleeding from the nose. Bleeding of some degree was observed in 30 per cent of the 962 cases and, in general, epistaxis bore no relation to the severity of the disease as it occurred in many of the mildest as well as in many of the most severe cases. It is noted in a report from the U.S.S. Northern Pacific that free hemorrhage from the nose occurred

--2468--

in many cases with general improvement in the condition of the patient; so much so that venesection was later practiced in severe cases with good effect. At the United States Naval Training camp, detroit, Mich., hemorrhage from the nose occurred in about 40 per cent of all cases of influenza and in some instances was very profuse. In all cases bleeding was limited to the anterior nares. On board the U.S.S. Wilhemina epistaxis occurred in practically all patients whose symptoms were of moderate severity.

At the United States Naval Hospital, Great Lakes, Ill., acute nasal hemorrhages occurred in a number of cases, apparently with beneficial results. In 9 among 2,924 cases of influenza, epistaxis was sufficiently severe to require packing. Ulcers of the septum were found in four cases.

Tongue and throat.--There was nothing characteristic about the tongue in ordinary influenza cases. In those which were severe or complicated the tongue was usually dry and leathery or it presented a dry beefy red surface covered with glairy mucus.

Sore throat occurred in about 20 per cent of the 900 Philadelphia cases and was the chief complaint in from 3 to 5 per cent. In Norfolk, slight soreness of the throat was a common manifestation. At the height of the epidemic in Boston it was noted that sore throat was not complained of in typical cases. In cases among the naval personnel in France, throat symptoms were few. In the Philippines, sore throat was a prominent symptom in many instances. On the whole, the throat was often congested but usually the patient did not complain of soreness. In the Great Lakes series streptococcus sore throat was occasionally observed. "The patient may or may not have sore throat in the very early stages of influenza--usually not. Not infrequently patients attributed the attack of influenza to a slight sore throat a few days previously, but he majority gave no history of previous illness."

Adenitis.--In a report from the United States Naval Hospital, Philadelphia, Pa., it was noted that a general adenitis was very frequently discovered upon examination. The whole chain of superficial glands was often involved, including the cervical, axillary, epitrochlear, and inguinal glands. Enlargement persisted during the course of the disease, but the glands seldom became larger than a pea or bean.

At the United States Naval Hospital, Great Lakes, Ill., cervical adenitis was seen occasionally and suppuration occurred in four instances among 2,924 hospital cases of influenza.

Blood.--In uncomplicated cases of influenza the leucocyte count was rarely above normal and usually below normal. In fact, a definite leucopenia was a striking feature and a most useful diagnostic sign in influenza all over the world.

The following is a composite blood picture in 100 uncomplicated cases of influenza:

White blood count		6,950
Polymorphonuclear leucocytes	per cent	67.5
Small lymphocytes	do	21.2
Large lymphocytes	do	3.8
Mononuclear leucocytes	do	4.4
Transitional cells	do	2.1
Eosinophiles	do	.7
Basophiles	do	.3

--2469--

The following is a composite blood picture in 100 cases of influenzal pneumonia:

White blood count		17,680
Polymorphonuclear leucocytes	per cent	82.8
Small lymphocytes	do	8.3
Large lymphocytes	do	2.1
Mononuclear leucocytes	do	2.6
Transitional cells	do	3.8
Eosinophiles	do	.3
Basophiles	do	.1

A report of influenza cases treated in the United States Naval Hospital, Chelsea, Mass., during the height of the primary epidemic states that the average white count was 4,900, but that over half the patients had white counts of less than 3,000 and that the cases in which broncho-pneumonia developed all showed a low blood count.

At the United States Naval Hospital, Puget Sound, Wash., the following findings were obtained in 10 fatal cases of the acute hemorrhagic pneumonitis type attributed to severe streptococcus septicemia complicating influenza.

Case No.	Admitted.	Died.	Average temperature.	Average white count.
1.	24	24	104.0-105.0	⁽¹⁾
2.	24	26	105.0	4,000
3.	25	27	103.0-105	3,400
4.	25	27	104.0-105	1,500
5.	26	27	104.6-105	3,000-4,000
6.	24	28	104.6-105.6	5,400
7.	24	28	103.0-104	6,800
8.	25	29	105104 104	4,000
9.	29	30	104104 104	4,600
10.	25	30	103.8	3,800

⁽¹⁾ Not taken. Dead two hours after admission.

At the United States Naval Hospital, Great Lakes, Ill., in 571 cases of influenza and influenzal pneumonia blood findings were:

White-blood counts of--		Per cent.
	5,000 or less were found in	15.5
	between 5,000 and 10,000 in	38.3
	between 10,000 and 15,000 in	22.9
	15,000 or over in	24.1

It was noted that counts taken during the height of the acute attack shortly after admission to hospital showed a normal count or a definite leucopenia in practically every case.

A report from the United States Naval Hospital, Philadelphia, Pa., stated that a high or rising white count was maintained in cases of influenzal pneumonia which were progressing favorably, although a falling count, while in general indicating an unfavorable clinical state, seemed not necessarily to define a fatal issue. Many cases with white counts slowly decreasing for several days eventually recovered. An interesting and valuable observation in daily blood examinations was the gradual or sudden change from the blood picture of uncomplicated influenza to that of influenzal pneumonia. By noting the rising white count and reduction in the percentage of small lymphocytes it was frequently possible to anticipate clinical findings of broncho-pneumonia by several days. In a few instances neutrophilic

--2470--

degeneration of polynuclear leucocytes was observed and marked granulation of lymphocytes was noted in one case in a series of over 200 blood examinations.

The following tables show in detail the leucocyte and differential count findings in different series of uncomplicated influenza cases and in different series of influenzal pneumonia cases:

Table No. 19.--Leucocyte counts in 28 early cases of influenza from one war, United States Naval Hospital, Chelsea, Mass., Sept. 1918.

Cases.	W.b.c.	Poly.	Lymph.	L. Mono.	Trans.	Eosin.	Baso.
1	6,200	76	20	2	2	------	------
2	6,800	25	38	1	5	------	1
3	8,400	77	14	3	6	------	------
4	10.000	73	25	1	1	------	------
5	5,600	44	50	------	6	------	------
6	6,800	72	24	2	2	------	------
7	7,200	80	20	------	------	------	------
8	7,200	88	12	------	------	------	------
9	4,400	54	44	2	------	------	------
10	8,000	74	20	4	2	------	------
11	6,800	68	30	2	------	------	------
12	6,600	52	45	------	2	1	------
13	4,200	60	40	------	------	------	------
14	4,600	50	46	2	2	------	------
15	5,200	52	46	2	------	------	------
16	5,800	48	52	------	------	------	------
17	4,200	48	52	------	------	------	------
18	6,800	64	28	4	2	2	------
19	7,200	72	26	------	------	2	------
20	6,800	68	30	------	2	------	------
21	4,600	66	34	------	------	------	------
22	5,800	40	56	------	4	------	------
23	8,600	75	24	------	------	1	------
24	7,200	78	16	4	2	------	------
25	4,400	56	36	4	4	------	------
26	4,200	68	32	------	------	------	------
27	5,000	70	28	2	------	------	------
28	5,400	56	43	------	1	------	------
Average	6,700	63.7	33.3	1.2	1.2	.21	.035

Table No. 20.--Leucocyte counts in 25 cases of typical influenza, United States Naval Hospital, Philadelphia, Pa., Sept. 26 to Oct. 26, 1918.

W.b.c.	Poly- nuclear.	Small lymph.	Large lymph.	Mono- nuclear.	Trans- itional.	Eosino- phile.	Baso- phile.
5,600	58	36	2	3	1	------	------
4,800	65	30	4	1	------	------	------
6,300	68	20	7	3	1	1	------
8,400	80	15	2	2	1	------	------
5,100	77	12	------	6	5	------	------
8,000	65	15	5	10	5	------	------
8,000	77	10	------	11	2	------	------
6,800	55	28	4	10	2	------	------
7,900	58	27	------	12	------	3	------
3,500	80	8	6	4	2	------	------
6,300	80	20	------	------	------	------	------
4,900	71	26	1	------	2	------	------
7,000	79	12	6	3	------	------	------
8,000	76	15	4	2	3	------	------
6,700	61	21	10	7	1	------	------
5,800	80	10	5	2	3	------	------
3,600	67	23	------	7	3	------	------
6,500	63	29	------	5	3	------	------
5,800	77	18	1	3	------	1	------
7,200	71	20	6	------	2	------	1
6,900	71	19	4	------	3	2	1
7,100	73	22	3	1	1	1	------
5,900	69	22	4	------	3	2	------
6,900	71	19	4	------	3	2	1
5,400	65	25	2	6	2	------	------

6,336	69.5	19	3	4	2	1.5	1

--2471--

Table No. 21.--Leucocyte counts in 31 cases of influenzal pneumonia from one ward, United States Naval Hospital, Chelsea, Mass., Sept., 1918.

Case.	W.b.c.	Poly.	Lymph.	Trans.	L. Mono.	Baso.	Eosin.	Temp- erature ° F.
1	26,200	81	18	1	------	------	------	104
2	29,000	89	10	1	------	------	------	100
3	14,600	73	26	1	------	------	------	104
4	14,600	80	19	------	------	1	------	100
5	13,600	71	24	3	------	2	------	104
6	10,000	82	17	1	------	------	------	99
7	37,000	75	20	1	2	2	------	103
8	17,600	75	16	4	5	------	------	102
9	29,900	91	8	1	------	------	------	100
10	17,200	78	19	2	1	------	------	103
11	10,000	78	20	2	------	------	------	99
12	7,000	88	10	2	------	------	------	99
13	13,000	80	20	------	------	------	------	102
14	17,000	87	10	3	------	------	------	104
15	13,600	86	12	------	2	------	------	102
16	28,800	82	14	2	2	------	------	102
17	4,600	78	19	2	1	------	------	103
18	14,800	96	4	------	------	------	------	104
19	12,600	70	28	2	------	------	------	105
20	12,200	84	16	------	------	------	------	103
21	7,800	67	29	3	1	------	------	101
22	6,400	66	34	------	------	------	------	104
23	7,400	53	46	1	------	------	------	101
24	10,000	56	42	2	------	------	------	99
25	3,600	84	16	------	------	------	------	104
26	16,800	60	36	3	------	------	1	99
27	6,800	56	40	4	------	------	------	104
28	9,000	61	36	3	------	------	------	99.5
29	12,200	82	16	2	------	------	------	103
30	15,800	76	22	2	------	------	------	100
31	19,400	78	18	2	2	------	------	102
Average	13,980	76.23	21.45	1.61	.52	.16	.03	101.8

Table No. 22.--Leucocyte counts in 25 cases of influenzal pneumonia, United States Naval Hospital, Philadelphia, Pa., Sept. 26 to Oct. 26, 1918.

W.b.c.	Poly- nuclear.	Small lymph.	Large lymph.	Mono- nuclear.	Trans- itional.	Eosino- phile.	Baso- phile.
22,600	95	2	1	------	2	------	------
13,600	88	6	1	2	3	------	------
12,100	75	3	3	9	6	2	2
16,000	77	13	4	1	3	2	------
16,500	85	10	------	1	4	------	------
12,000	89	3	------	4	4	------	------
15,600	90	1	1	2	6	------	------
49,900	86	------	1	1	12	------	------
69,600	92	2	------	1	5	------	------
24,300	87	2	2	4	5	------	------
22,800	88	12	------	------	------	------	------
14,000	86	7	------	2	5	------	------
20,200	84	3	4	4	5	------	------
19,000	91	2	1	1	5	------	------
43,000	98	1	------	1	------	------	------
25,600	82	10	1	2	5	------	------
25,000	82	2	2	9	5	------	------
20,900	86	5	------	4	5	------	------
17,500	77	20	1	1	1	------	------
18,900	81	14	------	4	1	------	------
19,600	78	12	5	1	3	1	------
15,600	78	10	5	4	2	1	------
23,800	82	16	------	------	2	------	------
13,600	82	17	------	------	1	------	------

23,212	85.24	7.04	1.28	2.32	3.8	.24	.08

Urine.--Reports indicate that serious renal complications were very rare. At the United States Naval Hospital, Great Lakes, Ill., albumin was reported present in about 20 per cent of the urines examined.

--2472--

Casts were found only occasionally. Acute nephritis with bloody urine and edema occurred in 7 of 2,924 cases of influenza.

On board the U.S.S. Solace albumin and granular casts were found in the urine in about 10 per cent of the cases treated.

At the United States Naval Hospital, Philadelphia, Pa., in nearly all cases seriously ill the urine contained albumin and occasionally casts, but there was never acute involvement of the kidneys or evidence of serious renal changes. Functional kidney tests made with phenol-sulpho-phthalein were unsatisfactory and did not give any information of importance. There were a number of cases of retention of urine necessitating catheterization a few times. Of 2,130 urines examined, 614, or 28.8 per cent, contained albumin; 204, or 9.6 per cent, pus cells. Casts were present in 192 or 8.6 per cent. Passive congestion of the kidneys was common. The urine was diminished in quantity and usually showed only a trace of albumin, high specific gravity, a few hyalin and granular tube casts, and not infrequently a number of red blood cells. These findings were sometimes interpreted as indicating acute toxic nephritis, but clinically it was impossible to recognize evidence of uremia, the symptoms of which, if present, were merged in the picture of toxemia.

Skin.--Judging from Navy reports, lesions of the skin were neither common nor characteristic. Herpes of the face, erythema, purpuric spots, purpura hemorrhagica and eruptions more or less like those of scarlet fever and measles were mentioned in a few reports.

A report from the United States Naval Hospital, Philadelphia, Pa., states that a papular eruption was observed on the back and, to a lesser extent, on the front of the body in many cases upon admission ito hospital or later during the course of the disease. The papules were frequently capped with minute pustules varying in size from pin point to pinhead.

Urticaria occurred not infrequently in cases where serum was used.

Source: Annual Report of the Secretary of the Navy, 1919 -- Miscellaneous Reports. (Washington: Government Printing Office, 1919). pp 2414-2506.