Onchocerciasis Elimination Mapping Project

Sightsavers has been working 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 10,200 people were surveyed. This was the first time river blindness has been surveyed in Mozambique using modern techniques.

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

The gallery below shows photos from the project in Nigeria and Mozambique.

What has the OEM Project achieved so far?

• 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 have 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 will be examined in early 2021, which will lead to the development of next steps if treatment is required to interrupt transmission in the country.

What’s next?

The results from the countries will establish 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 will also continue coordinating with partners focused on strengthening national laboratory capacity for diagnostic processing.

National onchocerciasis programmes and partners will then be encouraged to prepare for OEM by reviewing their own data and identifying districts that have not yet been treated or mapped.

The goal

The aim for OEM is for river blindness to be eliminated, and for partners to collaborate to map onchocerciasis in areas of Africa where the disease is less prevalent.