Morbidity due to Loiasis: population-wide evaluation and identification of pathogenic mechanisms

Loiasis, an infectious disease caused by the parasitic worm Loa loa, affects more than 15 million individuals in central Africa, and more than 100 million people are potentially exposed to infection.

Since its first description in 1770, the international scientific community has considered this filarial disease as benign. I recently demonstrated that loiasis significantly reduces the life expectancy of infected people.

I aim to definitively shift the prevailing paradigm of benign loiasis by showing that it can induce severe complications in various organs.

I will conduct the first population-wide evaluation of morbidity in rural areas of Central Africa by performing systematic examinations on 4,900 selected individuals.

This sample size will enable accurate estimation of prevalences of cardiovascular and renal diseases and of functional asplenia. Our results may lead to the recognition of loiasis as a significant public health problem. Such recognition could motivate integration of loiasis into the WHOs list of Neglected Tropical Diseases.

In addition, should loiasis be found to induce a functional asplenia, combating this disease could have a huge impact on the incidence and severity of other severe and common infections favoured by asplenia, such as malaria and pneumonia. Incidentally, specific recommendations regarding pneumococcal vaccination in loiasis-endemic areas could be made.

Another possible consequence of our findings is changes in the management of people identified as having high levels of Loa loa infection during routine surveys or onchocerciasis elimination activities.

Presently, these people are excluded from ivermectin treatment (because of the risk of post-treatment encephalopathy), and little is done to lower their level of infection.

Confirmation that loiasis can cause serious complications would motivate an ethical obligation to develop strategies to manage these cases in order to lower their burden of the disease.