Alternative intervention strategies for accelerating onchocerciasis elimination

Main Objectives

To determine if implementation of AIS accelerates onchocerciasis elimination in Massangam HD, measured through blackfly infectivity rates, microfilariae prevalence in the human population and presence of ov-16 antibodies in children
To assess the acceptability and tolerability of the population to uptake of the ‘test and treat’ strategy with doxycycline and ivermectin semi-annual mass distribution of ivermectin (as appropriate)

Summary

Onchocerciasis is a potentially blinding disease caused by an infection with onchocerca volvulus, transmitted by the bite of the blackfly. Epidemiological and entomological surveys conducted in 2015 and 2016 in the West Region of Cameroon showed evidence of an ongoing transmission of O. volvulus infection in the Massangam health district, despite 18 years of uninterrupted annual mass distribution of ivermectin.

Previous research by Sightsavers has investigated why this area is struggling to reach elimination targets and has identified a focus of high ongoing transmission that will require a new strategic approach if elimination is to be achieved.

This study will use a multi-faceted approach to reduce the reservoir of infection in the focus, through the use of a new treatment approach, testing individuals for onchocerciasis infection and treating those positive with doxycycline. The project will also target the blackfly population by larviciding their breeding sites. Communities outside this focus of high transmission which are closer to elimination but still require intervention, will receive ivermectin twice a year (currently it is only once) and behaviour change efforts will be made to improve compliance for taking the drug.

The aim of this study is to investigate the impact of these alternative intervention strategies on progress towards elimination in this HD and provide lessons learned for potential scale-up of this approach to other problematic areas where elimination is proving difficult.