Assessment of Microfilarial load in the blood of patients with Mansonella Perstans infection after anti-wolbachial treatment with Doxycycline

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Mansonella perstans is a vector-borne parasite; transmitted by tiny female bloodsucking insects of the genus Culicoides (biting midges). It is more prevalent in Sub-Saharan Africa. Most antifilarial drugs including ivermectin and DEC, and also benzimidazoles such as mebendazole, albendazole, levamisole, and thiabendazole, have proven ineffective against M. perstans. Therefore, this study was undertaken to assess the efficacy of doxycycline against M. perstans in the Asante Akim North District of Ghana. The study was an open randomized trial conducted in 8 communities of the Asante Akim North District. Out of a total of 1,229 individuals microscopically screened, 405 individuals were microfilaria-positive representing an overall prevalence of 33.0%. There was no significant difference (p=0.0568) between prevalence among males and females. Based on the findings from the initial blood samples, 102 eligible individuals were randomized to Early and Delayed groups. Individuals received 200mg of doxycycline daily for 6 weeks. The former group started medication at the initial stage while treatment was delayed for 6 months in the latter group. Five individuals who were not available during treatment, served as controls. Blood samples were taken and analyzed for microfilaria at 4 and 12 months of the study period. There was no significant difference (p=0.7655) between treatment groups at baseline level. Microfilarial load reduced marginally at 4 months even though there was no significant difference (p=0.5559) between the two treatment groups. However, at 12 months, the efficacy of doxycycline was evident. The Early group had a drastic reduction of microfilarial load resulting in significant difference between the two groups (p<0.0001). The distribution of microfilarial load among the controls throughout the study time points was relatively constant. A total of 10 individuals reported mild adverse events that resolved spontaneously. A well-designed specific real-time quantitative polymerase chain reaction (qPCR) was used to confirm M. perstans in the blood. Although PCR is arguably very sensitive, microscopy still remains reliable in the detection of M. perstans.
A thesis submitted to the department of clinical Microbiology, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements for the degree of Master of Philosophy in Clinical Microbiology School of Medical Sciences, College of Health Sciences.