Human African trypanosomiasis amongst urban residents in Kinshasa: a case-control study.

BACKGROUND: Increasing numbers of human African trypanosomiasis (HAT) cases have been reported in urban residents of Kinshasa, Democratic Republic Congo since 1996. We set up a case-control study to identify risk factors for the disease. METHODS: All residents of the urban part of Kinshasa with parasitologically confirmed HAT and presenting for treatment to the city's specialized HAT clinics between 1 August, 2002 and 28 February, 2003 were included as cases. We defined the urban part as the area with contiguous habitation and a population density >5000 inhabitants per square kilometre. A digital map of the area was drawn based on a satellite image. For each case, two serologically negative controls were selected, matched on age, sex and neighbourhood. Logistic regression models were fitted to control for confounding. RESULTS: The following risk factors were independently associated with HAT: travel, commerce and cultivating fields in Bandundu, and commerce and cultivating fields in the rural part of Kinshasa. No association with activities in the city itself was found. DISCUSSION: In 2002, the emergence of HAT in urban residents of Kinshasa appears mainly linked to disease transmission in Bandundu and rural Kinshasa. We recommend to intensify control of these foci, to target HAT screening in urban residents to people with contact with these foci, to increase awareness of HAT amongst health workers in the urban health structures and to strengthen disease surveillance.

Registration of the number of macules in paucibacillary leprosy for evaluation of early diagnosis and individual prognosis.

The number of macules is usually registered at diagnosis in the first clinical examination of leprosy patients. The question studied here is whether this practice is of any interest as an indicator of the precocity of detection of the prognosis. The study is based on the 26,996 paucibacillary patients detected from 1957 to 1982 in Polambakkam Leprosy Centre (South India) for whom the number of macules and disability status are assessed and registered. Several observations suggest that the proportion of single-macule patients among the newly detected cases is a more sensitive indicator than the proportion of new patients with disabilities for the evaluation of the delay between onset of the disease and detection. Its use could be especially helpful for programmes running for several years, when it becomes difficult to observe significant variations in the proportion of patients with disabilities. Regarding the prognosis value of the number of macules, inactivation and relapse probabilities were calculated. Regularity of treatment is found to be a better predictor of early inactivation than the number of macules, while relapse probabilities are more affected by the number of macules.