Onchocerciasis Elimination Mapping Project

Sightsavers worked with partners to develop stronger, standardised and more efficient ways of mapping the spread and transmission of river blindness (onchocerciasis), to work towards elimination.

Onchocerciasis elimination mapping (OEM) is the process of assessing if areas currently not being treated for river blindness need to be included in treatment programmes. Lack of standardisation and a clear process to follow has hampered completion of OEM.

The small-scale pilot surveys took place in Nigeria and Ghana in 2018 and early 2019. These surveys were in areas that have never been treated with ivermectin (the medication used to control the spread of the disease). The aim was to refine and validate the protocol for conducting OEM, as recommended by the WHO’s Onchocerciasis Technical Advisory Subgroup, and develop technical expertise in the project countries as well as standardised tools to ensure future mapping adheres to WHO standards.

In November 2019, the project expanded across Mozambique to help assess the prevalence of river blindness in the country. Mapping took place in seven districts and more than 10,200 people were surveyed. This was the first time river blindness had been surveyed in Mozambique using modern techniques.

The collaborative project was carried out in close coordination with the WHO and WHO/ESPEN, the Task Force for Global Health, the Bill and Melinda Gates Foundation and many other partners.

What did the OEM Project achieve?

• During the first few months of the project, we coordinated with national programmes, built coalitions and devised a training curriculum, and looked at procurement processing and refinement of key operational research questions.
• An external Programme Advisory Group of onchocerciasis experts met in March 2018 to discuss OEM data collection forms, management and communication strategies, exclusion mapping, and the methodological approaches for the pilots based on OTS recommendations.
• Fieldwork in Nigeria, Ghana and Mozambique was completed, where more than 15,000 people were surveyed and tested for exposure to the parasites that cause river blindness – 1,810 in Nigeria, 3,621 in Ghana, and 10,200 in Mozambique.
• Results from the pilot in Nigeria and Ghana demonstrated that certain areas considered to be a low priority for treatment under a control programme may need ivermectin treatments to eliminate the disease from the country. These results were presented at the third meeting of the Onchocerciasis Technical Advisory Subgroup.
• Results from Mozambique were examined in early 2021, which led to the development of the next steps to determine if treatment was required to interrupt transmission in the country.

What happened next?

The results from the countries established best practices for data collection, data visualisation and decision-making, with a view to create a template for scaling up OEM in other countries. The project continued coordinating with partners focused on strengthening national laboratory capacity for diagnostic processing.