River blindness is a disease transmitted by biting flies, affecting areas such as West Africa, Nigeria, Congo, the Central African Republic and Central and South America, and causing significant health problems for at least 18 million people. The flies carry a parasite called Onchocerca volvulus, which lays microscopic worms in the human host. The body's immune response towards these worms can lead to eye opacities, eventually causing blindness, and in some cases, skin disease.
The team have developed a mathematical model, published online in Proceedings of the National Academy of Sciences, which measures exposure by looking at how often people were bitten by the flies carrying the parasite. The new model can also be applied globally, unlike previous models which only looked at one geographical area, limiting how well they could be applied.
Dr João Filipe, from Imperial College London, and first author of the paper said: "This new model could be an important tool in developing effective health campaigns to reduce the numbers affected by river blindness. Currently there are at least 18 million people worldwide affected by this parasite, and more action is urgently needed. This model will help in the fight against the disease by providing a better understanding of the role of exposure to the biting flies that transmit river blindness"
The new model uses data from three regions, Cameroon, Central Guatemala, and Southern Venezuela, and looks at human age and sex. The team estimated entomological factors, such as the number of times people were bitten. This could be affected by anthropological factors, such as the level of protection against bites afforded by clothing.
Dr María-Gloria Basáñez, from Imperial College London, and senior author of the paper, said: "Although river blindness is a major cause of ill health round the world, it is an often overlooked disease as it only affects the poorest tropical areas. Greater investment needs to be made in public awareness campaigns to reduce exposure to it in the affected countries."
The researchers are from Imperial College London, Institut de Recherche pour le Développement, France, Institut für Tierphysiologie, Germany, Universidad Central de Venezuela, and the Centro Amazónico de Enfermedades Tropicales, Venezuela.
The work was supported by the Medical Research Council.
Journal
Proceedings of the National Academy of Sciences