Estimating the incidence is a difficult task and is fraught with uncertainty of the estimates. The World Health Organization (WHO)estimates the incidence of cases by country from various sources. The above is a summary of the estimated incidence of tuberculosis by WHO region for 1990 and 2006. It suggests that tuberculosis incidence has increase most in Africa, followed by Europe (largely due to the populous countries of the former Soviet Union), while in other regions it may have decreased some.
