The use of human sweat metabolites as bait for monitoring vectors of onchocerciasis in West Africa and Latin America

Onchocerciasis or river blindness is a parasitic disease caused by infection from the nematode Onchocerca volvulus. The parasite is transmitted to humans by black fly vectors of the genus Simulium. Most of the infections occur in central Africa, with significant incidence also in Central and South America. The World Health Organization (WHO) estimates 18 million people suffer from onchocerciasis. However, it is difficult to accurately access infection due to a prolonged period from infection to symptoms appearing in hosts. The current method for monitoring the spread employs human bait, which is neither optimal nor ethically sound. The need for a new monitoring method is crucial. It was noticed that anthropophilic gravid flies are attracted to human scent. This study will describe our efforts to identify key primary metabolites in human sweat. These compounds were taken onsite to breeding areas of S. ochraceum and S. damnosum in Southern Mexico and West Africa to identify which compounds attracted these vectors of onchocerciasis. The identified compounds will be developed as bait for a field trap for monitoring vector pressure in both Latin America and Africa.