Last week, Colombian health officials announced that the tropical disease river blindness has been completely eradicated, making it the first country in the world to successfully eliminate the parasitic condition within its borders. This victory was the result of the combined efforts of Colombia’s Health Ministry, the Pan American Health Organization, and local, U.S., and international charities and NGOs over 16 years.
Also known as onchocerciasis, river blindness was discovered in Guatemala in 1917, and is the second most common from of infectious blindness in the world. It is caused by a species of roundworm called Onchocerca volvulus. The parasite, which is carried by a black fly often found along rivers, has a symbiotic relationship with a bacteria called Wolbachia. Initially, the bacteria infects the skin. As the name suggests, the disease also strikes the eye. Damage can occur in any part of the eye, but the parasites generally move to the cornea, gradually turning the lens opaque.
River blindness has been the target of large-scale eradication efforts in the various regions in which it is found since 1974. In addition to the Colombia program, an example is the African Programme for Onchocerciasis Control, which has also make significant strides, though dealing with a larger population of people at risk. There is no really effective preventative treatment for the disease itself, though netting and insecticides can help get rid of the flies that carry it. Since the flies transmit the illness from infected people to uninfected people, treating the disease has the additional benefit of preventing its spread. The primary medication used for this is ivermectin, which prevents the parasite from reproducing—though it doesn’t have any effect on the adults—stops vision loss, and renders the infection no longer transmissible. In addition, the antibiotic doxycycline is used to destroy the bacteria, though it’s more difficult to distribute in effective quantities.
The success of the eradication program in Colombia points to the possibility of eliminating it elsewhere as well. Nearly 800,000 people have suffered partial or total vision loss due to river blindness, many in South America but mostly in Africa. Incidence of the disease in Africa has declined by a third in the past 15 years, and is expected to further decline. In addition, the efforts to get rid of river blindness in Colombia and elsewhere have brought people together for a variety of projects that improve health and quality of life.