How Many Get River Blindness

It has been found all across the world, even in the U.S. It can be found where the simulium blackflies live in near rivers and streams. Overall it is typically found in third world countries that don't have the protection and pesticides for elimination.

123 million people are at risk for getting infected with the parasite (WHO, 2013). It is believed that 25 million people at this moment have river blindness but only 300,000 are completely blind and 800,000 have some sort of vision impairment (WHO, 2013). You would need to live near a river with blackflies and have been bitten more than a fe times, typically if you travel to a place with blackflies you would need to stay more than three months before it would ever get the parasite into you.

Just like mosquitos in order for blackflies to reproduce the female flies need to take the blood of a human for ovulation. When the fly bites it than releases larva into the skin where it matures (takes about three months to a year) The larva inside the human body can stay alive for 2 years. Adult worms can stay alive from 15 to 30 years. Of course this disease can become latent and may not have any sighns or symptoms. The larva and adults can move around without being attacked by the immune system.  The parasites can make nodules under the skin in places including the genitals, face and legs. When the worms die it causes the immune system to go haywire, producing an intense itch all across the body. You can't sooth this terrible itch, because the itch lies under the skin. with treatment the itching will stop in a year without treatment it could last a lifetime. 

Women with skin Nodule 

Woman who itched the unbearable sratch

Photo: WHO/TDR/Stammers