Onchocerciasis is a skin disorder caused by blackfly. They act as transmitters to carry the worm of Onchocerca volvulus. The blackfly usually breed on the rivers and streams spreading the infection to the people who live nearby. For this reason this disease is also called as “river blindness”.
Once the worm enters the human body it produces thousands of larvae inside which would then migrate to the eye and skin causing infection. In rare cases it can cause blindness or partial loss of vision. Mortality rates are less common due to this disease but it is expensive to treat.
Blindness caused by onchocerciasis can be prevented by little extra care. More than 18 million people are affected worldwide by this infection and at least 2 million people have become blind. This disease is widespread in Africa and some parts of Latin America and Yemen.
River Blindness Causes :
This disease is caused by the bite of blackfly that transmits the worm into the blood. It is the female flies by name Simulium that commonly stings human blood and transmits the parasite inside.
The larva of the parasite occurs in stages and the fly will introduce the larvae in 3rd stage into the skin of our body. The male worms will reside safely on the nodules of connective tissues which will then move inside to locate female worms for mating. In this process the female worms will produce thousands of micro-filarial worms inside the body. It is capable of producing about 1800 eggs per day. These worms lie predominantly on the skin and on the lymph nodes of connective tissues and only in rare cases it enters into the peripheral blood and passed out through the urine or sputum.
River Blindness Symptoms :
The first symptom of worm infection will occur only after a year or even more. Till that period the worm lies dormant on the human skin safely migrating and multiplying inside. Some of the early symptoms are joint pain, fever, and hives on the skin. Often there are no symptoms for many people and hence this disease is difficult to diagnose.