African Programme for Onchocerciasis Control (APOC)

Mapping co-infection with Loa loa (RAPLOA)

Assessing the prevalence of Loa loa
To rapidly assess the presence of Loa loa in a community, people are asked if they have seen evidence of the eye worm with the aid of a photo

Severe, sometimes fatal, adverse reactions can occur in people who take ivermectin for the treatment of onchocerciasis and who have a high intensity of Loa loa (eye worm) infection. The risk of severe adverse reactions is considered to be unacceptable in onchocerciasis-endemic communities where more than 20% of the population also has loiasis. It is very important, therefore, to assess the level of loiasis endemicity in a community before initiating mass treatment against onchocerciasis.

RAPLOA is a rapid assessment procedure for Loa loa, developed by the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) with financial support from APOC. The tool uses a simple questionnaire on the history of visible worms moving in the lower part of the eye, to predict whether or not loiasis is present at high levels in a community.

Results from RAPLOA help in the planning of community-directed treatment with ivermectin, by predicting where ivermectin treatment for onchocerciasis can be safely implemented.