Onchocerciasis, the blindness of rivers

• April 28, 2024

This tropical disease affects 18 million people in the world. It is the second cause of blindness on the planet with 270 thousand blind people and another 500 thousand people who suffer from serious visual problems. Although it has always been considered a typical African disease, since 1991 the Program for the Elimination of Onchocerciasis in the Americas (OEPA) has been launched with the aim of eradicating this disease that harms the life of more than half million people on the continent.

Onchocerciasis is produced by a worm called Onchocerca volvulus that damages the skin and can cause serious damage to the eyes until people are blind. The worm is transmitted through the bite of insects commonly known as gnats, black flies or sorrel and that live in streams.

From the rash to blindness

Once the worm or infective larvae are inoculated into the skin, itching, rashes and swelling occur. When they reach adulthood, the worms cause a reaction in the patient by which they end up encapsulated in fibrous tissue where they remain and reproduce by exporting microfilariae (tiny worms) to the whole body.

Over time, the infected person has so many small worms inside that the manifestations on their skin become severe and severe, although the worst thing is the decrease in vision.

Discover onchocerciasis to fight it

The OEPA points out that when there is a suspicion that there is onchocerciasis in a community, different procedures are carried out to confirm or dismiss the doubts. One of these is the so-called Rapid Epidemiological Evaluation (EER), which consists of performing biopsies on a group of people in the population.

Since 1987, the company Merck Sharp & Dohme has been producing Mectizan®, distributing a drug containing ivermectin free of charge that kills microfilariae for a period of 6 months, but does not affect the adult worms that are protected inside their capsules.

For this reason, the medicine must be given every six months for 12 or 15 years, time in which it is estimated that all adult worms will have disappeared, and with them, the possibility of losing sight, one of the most appreciated organs.

Video Medicine: Monsters Inside Me: River Blindness (April 2024).