Endemic mansonellosis in Emohua Local Government Area, Nigeria: human parasitaemia and Culicoides biting patterns

• Main Author: E.C. Uttah, S. Etim, C. Okonofua & O.E. Effiom
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2011-03-01
• Series: Journal of Vector Borne Diseases
• Subjects: Biting patterns; Culicoides sp; Mansonella perstans; mansonellosis; Nigeri
• Online Access: http://www.mrcindia.org/journal/issues/481041.pdf

Background & objectives: The study was aimed at elucidating the prevalence and intensity of Mansonellaperstans microfilaraemia in the Emohua Local Government Area, Nigeria, and ascertaining the abundance,circadian, and the annual biting patterns of the Culicoides vector.Methods: Thick smear of 50 μl finger-prick blood stained with Giemsa was examined microscopically in across-sectional study. Vector landing collection on human bait was employed in a longitudinal study of thevector biting patterns, carried out between July 2005 and August 2006.Results: Of 1486 individuals examined, 11.2% of both males and females were positive for M. perstansmicrofilaraemia. Microfilaraemia appeared early in life. The overall geometric mean intensity among those withpositive microfilaraemia was 117 mf/ml (121 mf/ml for males and 113 mf/ml for females). The differences ingeometric mean intensity between different age groups were statistically significant (one-way analysis of variance;p <0.05), being highest in the oldest age group (266 mf/ml). A total of 1183 female Culicoides sp were caughtfrom September 2005 to August 2006. The abundance of Culicoides sp was seasonal. The circadian bitingactivity had a broad peak between 0700 and 1200 hrs. The monthly biting rates ranged from zero bite per personper month in January 2006 to 1151 bites per person per month in June 2006. The annual biting rate was 7382bites per person per year.Conclusion: Majority of those with positive microfilaraemia were poor socioeconomically, underscoring theneed for health education and application of effective control measures against Culicoides biting midges inEmohua.