Infection rates with Leishmania donovani and Mycobacterium tuberculosis in a village in eastern Sudan

BACKGROUND: Leishmania-tuberculosis co-infection is not uncommon in clinical practice in East Africa, but little is known about the epidemiology of this problem at population level. A cross-sectional household survey was carried out in an active visceral leishmaniasis (VL) focus in Eastern Sudan in February 2002. METHODS: All inhabitants of Marbata village in Atbara River Area, Gedarif State, who gave informed consent, underwent both a leishmanin skin test (LST) and a tuberculin test for infection with L. donovani and Mycobacterium tuberculosis. All subjects were clinically screened for VL and tuberculosis (TB). RESULTS: About 66% (252 of 382) were LST-positive, 26% (100 of 382) were tuberculin-positive and 20% (77 of 382) were positive for both tests. By the age of 15, more than 60% of inhabitants were LST-positive, but <20% were tuberculin-positive. By the age of 30, these percentages increased to 100 and 50%. No association was found at the individual level between leishmanial and tuberculous infection after controlling for age. CONCLUSION: In this community study, we found no association between the risk of infection with L. donovani and M. tuberculosis. However, the progression to active VL disease might be different in M. tuberculosis-infected than in non-infected persons and vice versa. Prospective studies are needed to document the prognosis of TB/VL co-infection.