HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 34/4/921    most recent 09031936.00035309v1 Alert me when this article is cited Alert me if a correction is posted Permissions Request Permissions Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Naranbat, N. Articles by Rieder, H. L. PubMed PubMed Citation Articles by Naranbat, N. Articles by Rieder, H. L.

Seasonality of tuberculosis in an Eastern-Asian country with an extreme continental climate

¹ National Centre for Communicable Diseases, ² Mongolian Academy of Medical Sciences, Ulaanbaatar, Mongolia. ³ Institute of Infectious Diseases, University of Bern, Bern, Switzerland. ⁴ International Union Against Tuberculosis and Lung Disease, Paris, France.

CORRESPONDENCE: H. L. Rieder, International Union Against Tuberculosis and Lung Disease, 68 Blvd Saint Michel, 75006 Paris, France. E-mail: TBRieder{at}tbrieder.org

Keywords: Epidemiology, Mongolia, seasonality, temperature, tuberculosis

Received: March 1, 2009
Accepted April 6, 2009

Aggregate monthly notifications of incident sputum smear-positive tuberculosis (TB) in Mongolia, stratified by sex and age groups, were analysed separately for Ulaanbaatar, Mongolia, and the rest of the country for the 9-yr period from 1998 to 2006. TB notifications were compared with ambient surface temperature.

More than twice as many TB cases were notified in the peak month (April) compared with the trough months (October–December), paralleling the temperature curve. The fluctuations recurred consistently over the entire observation period, were identical in the capital compared with the rest of the country, and were independent of age and sex.

TB notifications parallel the temperature amplitudes and have a magnitude not reported elsewhere. We hypothesise that the influence of temperature on life either indoors or outdoors is consistent with the transmission probability of Mycobacterium tuberculosis and the subsequent delay to disease recognition and notification with the incubation period, possibly co-determined by other factors, rather than accessibility to services.