Onchocerciasis Entomological Surveillance and Modelling


Background: Onchocerciasis remains the major neglected tropical vector-borne parasitic disease in terms of funding, yet it’s burden claims the life of many resource-poor populations. Onchocerciasis control relies on treatment using of a single dose of ivermectin (Mectizan®) taken for the lifespan of the adult worm. The primary goal of Onchocerciasis control in Africa has recently shifted from morbidity prevention to elimination of the infection where possible by 2025. Historical site for Onchocerciasis control using both treatment and vector control is the Tukuyu Onchocerciasis focus located in Tukuyu in Rungwe district of southwestern Tanzania. The focus was earmarked among three sites in Africa for vector control using insecticide against larval stages in order to complement Community Directed Treatment with Ivermectin, with the financial support from the World Health Organization for a period from 1997 – 2005. Rationale: Vector elimination project was the first of its kind in Tanzania that resulted in disappearance in the focus, the Simulium vector species. Despite several success stories, Vector elimination project activities ended without further disease entomological surveillance. Ivermectin treatment started more than two decades ago, there seems to be concerns on recrudescence of diseases transmission in many part of Africa where Onchocerciasis was recorded to be eliminated. This recrudescence of disease transmission calls for a need of integrating vector control option. It is thus essential to undertake this entomological surveillance study so as to monitor the current status of Onchocerciasis transmission in the Tukuyu focus and also to develop mathematical models and machine learning tools to guide future decision using collected surveillance data. Objective: The specific objectives are to: (i) conduct fly catch and determine abundance, mark distribution and disease infection in selected sites within Tukuyu Onchocerciasis focus; (ii) conduct prospection surveys on abundance of aquatic stages of Simulium species in selected sites within Tukuyu Onchocerciasis focus and its surroundings; (iii) develop mathematical models for Onchocerca parasite transmission which incorporate the role of climate variability; and (iv) use machine learning to tools to predict patterns associated with Onchocerciasis elimination or recrudescence to enhance disease surveillance. Methods: This project will be implemented through four packages (as per specific objectives). Expected Output: The project results with provide guide Onchocerciasis control teams to make decisions on where and when to stop ivermectin treatment with successful disease control/elimination thus improved decision. Duration: This is a 5 years’ project Funding: The project is estimated to cost US$ 150,000.