The Epidemiology of Smear Positive Tuberculosis in Three TB/HIV High Burden Provinces of Kenya (2003–2009)

Interest in epidemiology of tuberculosis in Sub-Sahara Africa has been activated by its reemergence in the mid-1990s because HIV and poverty have created a lethal combination that propagates TB transmission. Three provinces of Kenya that collectively contribute to about 56% of TB cases notified in Kenya were included in the study. Data for smear positive TB and TB HIV was extracted from existing database between 2003 and 2009. Data was analyzed to produce trends for each of the provinces, and descriptive statistics were calculated. To deduce existence of differences in gender, provinces, and years, analysis of variance was carried out with values and confidence intervals generated. There were more males (56%) than females affected by TB, but more females with dual infection. Females have a bimodal peak in age groups 15–24 and 25–34, while males have one peak age group at 15–24. The rate of decline for males was higher than for females. Significant differences were found in gender ( ), year ( ), and rate of HIV positivity across the provinces ( ). Declining trend in cases is attributed to effects of integrating TB and HIV services and therefore programs need to address barriers to integrate care. 1. Background Interest in the epidemiology of tuberculosis (TB) has recently been activated worldwide by its reemergence especially in Sub-Sahara Africa where the highest case notification rates have been reported. In 2010, Africa contributed 26% of the global burden with nine out of the 22 high burden countries contributing 81% of the global burden coming from Africa. During this time, Kenya was ranked position 10 amongst the high burden countries [1]. From mid-1980s, Sub-Saharan Africa experienced an upsurge in TB cases notified with the upsurge of incident cases being attributed primarily to HIV [2–4]. These countries are low income countries where HIV and poverty have created a lethal combination that propagates TB transmission [5]. Although it is challenging to accurately measure, much of the recorded increase may have actually reflected real changes in the incidence of tuberculosis in the community. Kenya had an average 10% increase in incident TB cases over the last decade before signs of decline began to be seen. The increase is likely to be due to several factors which have been influencing tuberculosis trends for many years. However, the main reason for the increase in tuberculosis has largely been attributed to HIV epidemic and to the growth of poverty in urban settings [6, 7]. Over the years, TB disease seems to be getting more urbanized with time