Tuberculosis Bases De Su Epidemiologia

Epidemiologic Basis of Tuberculosis Control
First edition 1999

International Union Against Tuberculosis and Lung Disease

Epidemiologic Basis of Tuberculosis Control
First edition 1999

Hans L. Rieder International Union Against Tuberculosis and Lung Disease
68, boulevard Saint-Michel, 75006 Paris
The publication of this monograph was made possible thanks to the support of the WorldHealth Organization, the Norwegian Heart and Lung Association, the British Columbia Lung Association, the Anti-Tuberculosis Association of Thailand, the Finnish Lung Health Association and the French Ministry of Foreign Affairs.

Table of Contents

Preface.......................................................................................................................................................................... 5 Acknowledgements.................................................................................................................................... 7 Introduction.......................................................................................................................................................... 9
1.

Exposure to tubercle bacilli.................................................................................................. 11
Number of incident cases .................................................................................................................. 11 Duration of infectiousness ................................................................................................................ 12 Number ofcase-contact interactions per unit of time ............................................ 12
Population density Family size Differences in climatic conditions Age of sources of infection Gender

2.

Infection with tubercle bacilli .............................................................................................. 17
Etiologic epidemiology: risk factors for becoming infected given that exposurehas occurred .............................................................................................. 17
Airborne transmission through infectious droplet nuclei Characteristics of an infectious patient Air circulation and ventilation Reducing expulsion of infectious material from source cases Host immune response Other modes of transmission: M. bovis

Descriptive epidemiology: incidenceand prevalence of infection ................ 26 Methodological issues in measuring infection .................................................................................. 26
Evaluation of the sensitivity of the tuberculin skin test Problems with the specificity of the tuberculin skin test in veterinary medicine Standardization of tuberculin and dosage in humans Variation in the specificityof the tuberculin skin test with a standard tuberculin dose

-1-

Approaches to determining the prevalence of tuberculous infection in the presence of cross-reactions attributable to environmental mycobacteria Prevalence of infection .............................................................................................................................. 43 Prevalence of infection by ageand sex Prevalence of infection and population density Tuberculous infection and socioeconomic indicators

Predictive epidemiology: modeling risk of infection ................................................ 49
Deriving risk of infection from prevalence of infection Trends in risk of infection over time Extrapolation from risk of infection to age-specific prevalence of infection Risk ofinfection and infectious cases

3.

Tuberculosis .............................................................................................................................................. 63
Etiologic epidemiology: risk factors for disease given that infection has occurred .............................................................................................................. 63
Time...