Microfilaridermia assessment of the efficacy of Ivermectin alone and Ivermectin plus Albendazole against Onchocerciasis

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August 2015
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Onchocerciasis, commonly known as river blindness, is a vector-borne parasitic disease which affects approximately 37 million people world wide, mostly in sub-Saharan African countries. In Ghana, the standard treatment of onchocerciasis is annual mass drug administration with ivermectin at a dose of 150-200µg/kg. However, this regimen kills only microfilariae and therefore repopulation of microfilariae by adult female worms resumes 3 to 6 months after ivermectin treatment. In this study, an open-labelled clinical trial was conducted using microfilariae levels to assess the efficacy of ivermectin alone and ivermectin plus albendazole given annually and semi-annually. A total of 272 onchocerciasis-infected volunteers were randomised into ivermectin alone annually, ivermectin alone semi-annually, ivermectin plus albendazole annually and ivermectin plus albendazole semi-annual treatment arms. Participants in the annual treatment arms received vitamin C at 6 months. Microfilariae loads of all study volunteers were monitored at pre-treatment, 6 months and 18 months using skin biopsies. All four treatment arms significantly (p=0.0001) reduced microfilariae loads but the bi-annual treatment arms of ivermectin alone and ivermectin plus albendazole were the most effective regimens for clearing skin microfilariae. Ivermectin is therefore still effective in clearing microfilariae among participants in the Adansi South District of Ghana. Bi-annual treatment of ivermectin alone and ivermectin plus albendazole was found to have additional benefit in reducing microfilariae loads compared to annual treatment. However, co-administration of ivermectin (200µg/kg) and albendazole (800µg/kg) did not have additional effect of reducing microfilariae loads.
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Philosophy In the Department of Clinical Microbiology, School of Medical Sciences, College of Health Sciences, 2015