Influenza

by Warren T. Vaughan

AN EPIDEMIOLOGIC STUDY.[^[1]]

By WARREN T. VAUGHAN, M. D.

(Received for publication April 6th, 1921.)

CONTENTS

SECTION I.
		Page
General Epidemiologic Considerations		[1]
Historical		[2]
Clinical and epidemiologic identification		[13]
General characteristics of early epidemic outbreaks		[14]
Symptoms in former epidemics		[19]
Manner of spread		[20]
	Human intercourse	[23]
	Crowd gatherings	[26]
	Mass attack	[27]
	Healthy carriers and convalescents	[30]
General manner of spread in individual localities		[31]
	Primary type of epidemic	[31]
	Secondary type of epidemic	[33]
	Mortality curves	[36]
	Duration of explosive outbreak	[37]
	Morbidity curves in 1920 recurrences	[41]
Spread in countries and continents		[42]
	Spread in primary waves	[42]
	Spread in recurrences	[44]
SECTION II.
Influenza Epidemics Since 1893		[47]
Occurrence since 1893		[47]
	Period from 1893–1918	[47]
	Increase in 1900–1901	[49]
	Period from 1901–1915	[51]
	Influenza in 1915–1916	[55]
	Influenza between 1916 and 1918	[58]
The pandemic of 1918		[59]
	Date of first increased prevalence in various localities	[65]
	Influenza in China	[80]
	Autumn spread in the United States	[81]
	Recrudescences	[87]
Recurrences in the winter of 1919–1920		[89]
	The winter of 1920	[90]
Incubation period		[95]
Predisposing causes		[96]
Periodicity		[97]
Virulence enhancement		[108]
	Meteorologic conditions	[113]
	Secondary invaders	[114]
Origin of the 1918 pandemic		[116]
SECTION III.
An Investigation of Influenza in Boston (Winter of 1920.)		[127]
Diagnostic standards for the 1918 epidemic		[134]
Standards for 1920		[134]
Morbidity		[137]
	Relation of sex to morbidity	[143]
	Relation of sex to severity	[145]
	Morbidity by age	[145]
	Relationship of occupation to morbidity	[150]
	Effect of race stock	[155]
Mortality		[156]
	Mortality by sex	[165]
	Relationship to age	[167]
	Relationship of occupation	[170]
	Density of population	[170]
	Race stock and mortality	[173]
SECTION IV.
An Intensive Study of the Spread of Influenza in Small Groups of Closely Associated Individuals		[175]
Effect of overcrowding		[179]
Domestic cleanliness		[187]
Economic status		[189]
Distribution of the disease through the household		[191]
	The first case in the family	[194]
	Intimacy of family contact	[197]
	Recurrent cases	[198]
SECTION V.
Immunity		[199]
SECTION VI.
Influenza and Other Diseases		[212]
Influenza and tuberculosis		[212]
Other infectious diseases		[220]
Encephalitis lethargica		[222]
SECTION VII.
Comparison of Influenza with Other Epidemic Diseases		[224]
Epizootics		[224]
Asiatic cholera		[228]
Epidemic meningitis		[228]
Plague		[229]
Measles		[231]
SECTION VIII.
The Prevention and Control of Influenza		[234]
Anticipatory or preventive measures		[236]
Organization of health services		[237]
Palliative measures in the presence of an epidemic		[239]
Problems for the future. Constructive research		[241]
Bibliography		[245]

[1]. From the Department of Preventive Medicine and Hygiene, Harvard Medical School, Boston, Mass.

INFLUENZA.

AN EPIDEMIOLOGIC STUDY.

SECTION I.

General Epidemiologic Considerations.