LYMPHATIC-FILARIASIS IN BRAZILIAN URBAN AREA (MACEIO, ALAGOAS)

A cross-sectional survey conducted among evening students was used to determine the prevalence of Wuchereria bancrofti infection in Maceio, capital of the State of Alagoas, northeast Brazil. A single thick-bloo d smear was used, being collected between 10 p.m. and 12 a.m. From a t otal of 29,551 students enrolled at evening elementary schools in the 33 city sectors, 16,569 (56.4%) were random selected for inclusion in the study. From those, 10,857 (65.5%) were interviewed and examined an d 73 (0.70%) were found to have microfilaraemia. Autochthonous W. banc rofti carriers live in 10 of the 33 city sectors, suggesting a focal d istribution. Moreover 84% of infections were diagnosed among 29% of al l students examined, inhabiting three contiguous sectors at the city c entral area, presenting infection rates up to 5.3%. Students living in city sectors with prevalence of microfilariae carriers greater than 1 % were found to have a higher risk for infection when compared to stud ents from the rest of the town [Relative Odds (RO) 12.8, 95% CI 6.7 - 25.1]. Eleven positive individuals from non endemic areas were living in Maceio for more than 10 years; time of residence in the area was a major risk factor for infection among students not born in the region (p<0.01). Regarding sex, male students presented a higher proportion o f positive (RO 1.7, 95% CI 1.1 - 2.9).