Association between leprosy and HIV infection in Tanzania.

SETTING: An epidemiological study of the interaction of leprosy and HIV infection in Tanzania. OBJECTIVE: To establish the prevalence of HIV infection among leprosy patients, and to measure the association of HIV and leprosy by comparing the HIV prevalence in leprosy patients and blood donors. DESIGN: Testing for HIV infection in consecutively diagnosed leprosy patients (new and relapsed after MDT) in all regions in Tanzania successively for a period of 3 to 6 months during 1991, 1992 and 1993. RESULTS: Out of the total estimated eligible leprosy patients, 697 patients (69%) entered the final analysis. The HIV prevalence among these leprosy patients was 12% (83/697) as compared to 6% (8960/ 158,971) in blood donors examined in Tanzania during the same period. There were no significant differences in HIV seroprevalence by age, sex, residence or type of disease. However, the adjusted odds ratio (OR) of the presence of a BCG scar was 1.9 [95% confidence interval (CI) 1.1-3.3] among HIV-positive leprosy cases compared to HIV-negative leprosy cases. Comparing leprosy cases with blood donors as controls, the logistic regression model, controlling for sex, age group and residence, showed the OR for HIV seropositivity among leprosy patients to be 2.5 (95% CI 2.0-3.2). This association existed in all strata, but was strongest in the 15-34-year age group. No difference of HIV status between multibacillary and paucibacillary leprosy could be shown to exist. The point estimate of the population attributable risk of HIV infection for leprosy was 7%. CONCLUSION: HIV infection is associated with leprosy and might reverse the epidemiological trend of the slow decline in case notification in Tanzania if HIV infection is increasing greatly. Previous BCG vaccination loses its protection against leprosy in the presence of HIV infection. A repeated study is recommended in order to validate these findings, whereby recording of the disability grading of the cases is necessary to adjust for delay in diagnosis.

PIP: The association between HIV infection and leprosy was investigated in 731 consecutive leprosy cases from all 20 regions of Tanzania. These cases represented 69% of total notified new and relapsed leprosy cases reported in the 1991-93 study period. HIV prevalence among the 679 patients for whom complete data were available was 12% (83 cases). Leprosy patients aged 35-54 years and those without a BCG scar were significantly less likely than their counterparts aged 15-34 years and those with a BCG scar to be HIV-infected. There were no significant differences in HIV prevalence in terms of sex, urban or rural residence, new or relapsed cases, and paucibacillary or multibacillary leprosy. Among controls--all 158,971 blood donors tested for HIV during 1991 to 1993--HIV prevalence was 6%. The overall odds ratio for HIV infection among leprosy patients compared with controls, after adjustments for sex, age, and residence, was 2.5 (95% confidence interval, 2.0-3.2). Point estimates of the attributable risk and the population attributable risk were 57% and 7%, respectively. These findings indicate that HIV infection significantly increases the risk of leprosy in Tanzania and compromises the protective effect of BCG vaccination. Although case notifications of leprosy in Tanzania have not changed appreciably in the past 13 years, expansion of the HIV epidemic could have a significant effect on the epidemiology of leprosy.

Rifabutin (ansamycin LM 427): a new rifamycin-S derivative for the treatment of mycobacterial diseases.

Rifabutin (ansamycin LM 427), a semisynthetic spiropiperidyl derivative of rifamycin S, shows good in vitro activity against most mycobacterial species, including Mycobacterium avium complex. In animal models, the drug is more active against both Mycobacterium tuberculosis and Mycobacterium leprae than in rifampin, and studies indicate that rifabutin is active against some rifampin-resistant strains of both species. The drug has a long half-life (16 hr) in humans and a marked tissue tropism, with tissue levels five- to 10-fold higher than that in the serum. In animals rifabutin is no more toxic than rifampin. A large experience from the compassionate use of rifabutin for life-threatening mycobacterial infections in humans, most commonly disseminated M. avium complex disease in patients with AIDS, has also indicated relative drug safety. Although some data suggest that rifabutin is effective, firm conclusions about drug efficacy await results from controlled clinical trials.