Mansonella perstans filariasis in Uganda: patterns of microfilaraemia and clinical manifestations in two endemic communities

Surveys for Mansonella perstans infection and potentially related clinical manifestations were undertaken in two endemic communities in Mukono and Luwero districts of Uganda where no other human filarial infections are transmitted. A sensitive and accurate counting chamber method was used for quantifying microfitaraemia in 100 mu l of finger-prick blood. Among 575 and 991 examined individuals aged >= 1 year in the two communities, the overall microfilariae (mf) prevalence was significantly higher in Mukono (76.5%) than in Luwero (57.7%). As early as age 1-4 years, 40.6% and 20.5% of the children were mf-positive. Prevatences increased rapidly with increasing age to reach 89.2% and 81.4% in the 15-19 years age group and then remained high in subsequent age groups. The geometric mean mf intensity among mf-positive individuals was slightly higher in the Mukono community (32.4 mf/100 mu l) than in the Luwero community (29.9 mf/100 mu l), and this parameter increased with age in both communities. No obvious associations were observed between various clinical parameters and M. perstans microfitaraemia in any of the study communities. The observed patterns of microfilaraemia and the lack of obvious visible clinical manifestations suggest that the host's regutatory responses are downregulated in M. perstans infections. [ClinicalTrials.gov identifier: NCT00215280] (C) 2008 Royal Society of Tropical, Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.