A 16-year follow-up study on bancroftian filariasis in three communities of north-eastern Tanzania

The results of a 16-year, parasitological and clinical, follow-up study on bancroftian filariasis in three villages in north-eastern Tanzania are reported and analysed with respect to the long-term development of microfilaraemia and disease. The study revealed an extraordinary static situation, both at the community level and at the individual level. No significant differences were observed in any of the three villages, with respect to total or age-specific prevalences of microfilaraemia, hydrocele in males aged ⩾20 years or leg elephantiasis in all subjects aged ⩾20 years, when the results from 1975 were compared with those from 1991. Overall, 542 of the subjects (37·2% of the total) examined in 1975 were re-identified and re-examined in 1991. Of those microfilaraemic in 1975, 81·9% were also microfilaraemic in 1991. Similarly, 81·3% of those amicrofilaraemic in 1975 were also amicrofilaraemic in 1991. Thus, most subjects had the same microfilarial (mf) status at both surveys. The low mf loss rate indica...