The epidemiological delimitation of lymphatic filariasis in an endemic area of Brazil, 41 years after the first recorded case

In 2002, the status of lymphatic filariasis (LF) in the district of Jaboatão, in north-eastern Brazil, was reviewed, 41 years after the first case of the disease was recorded in the area. Current data from Jaboatão were compared with older information from the district that had been published, as official reports on filariasis cases and mosquitoes and as the result of population surveys, between 1948 and 1997. Although the first microfilaria-positive cases were detected in the district in 1959, it was not until 1993 that the national Ministry of Health categorized Jaboatão as an endemic area. In 2002, fingerprick samples of blood, each of about 50 microl, were collected at night (23.00-01.00 hours) from 4365 individuals in the district and used to make thick smears. Microfilariae were detected in the smears of blood from 33 (0.8%) of the subjects, 12 of whom were considered autochthonous cases of LF. The male subjects were significantly more likely to be microfilaraemic than the female (1.1% v. 0.4%; P<0.05) but there was no direct relationship between prevalence and age, the microfilaraemics varying in age from 6-64 years. The Socorro sub-district had the highest prevalence, of 2.9%. It is recommended that the National Programme to Eliminate Filariasis uses mass drug administrations and vector control throughout the district, regardless of the prevalences recorded in the latest survey.