RESEARCH ARTICLE i a

Full list of author information is available at the end of the articleBackground Tuberculosis (TB) is a major public health challenge. Globally there were an estimated 8.7 million incident cases of TB in 2011, 26 % of which occurred in Africa, and 1.4 million TB deaths [1]. 13 % (1.1 million) of the incident cases were HIV positive. In Malawi the number of TB cases notified to the National TB Control Programme rose sharply from 12,395 (132 per 100,000 population) in 1990 to 25,491 (199 per 100,000 popula-tion) in 2005 [2]. The upsurge in TB was largely due to HIV infection. HIV increases the risk of rapid TB progres-sion after primary infection or re-infection with Mycobac-terium tuberculosis (Mtb) and increases the risk of reactivating latent TB infection [3,4]. In HIV negative in-dividuals infected with Mtb, the lifetime risk of developin