Does Tuberculosis Have a Seasonal Pattern among Migrant Population Entering Iran?

Background There are few quantitative documents about the seasonal incidence of tuberculosis (TB) among immigrant populations. Concerning the significant role of recognizing seasonal changes of TB in improving the TB control program, this study determines the trend and seasonal temporal changes of TB among immigrants entering Iran.   Methods In this longitudinal study, data from the Iranian TB register Program (from ۲۰۰۵ to ۲۰۱۱) was used. The aggregated number of monthly and seasonal TB cases was obtained by adding the daily counts. Data was analyzed by Chi-square, Independent T-test, ANOVA, and Poisson regression using Stata ۱۱ and SPSS ۲۰ software.   Results Among ۷۴,۱۵۵ registered patients with TB, ۱۴.۳% (۱۰,۵۸۷) were non-Iranian who had immigrated to Iran from ۲۹ different countries. The highest aggregated number of seasonal and monthly incidence of TB in immigrants was observed in spring (۲۸۲۴, P= ۰.۰۰۷) and in May (۱۰۳۷, P< ۰.۰۰۱). The number of non-Iranian patients with TB increased significantly over the years (β= ۰.۰۱۶, P= ۰.۰۰۱).   Conclusion This study shows that immigrants constitute a significant portion of TB patients recorded in Iran and this trend is increasing. Also, the peak incidence of this disease is the second month of the spring.

Keywords:

Tuberculosis (TB) , Seasonality , Iran , Migrant