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River blindness persists in Africa

Health officials battle to combat 'forgotten disease' that leaves many villagers blind.

MNGAZI, Tanzania — A man with clouded eyes sits on the ground next to a wattle and daube hut in the riverside village of Mngazi. His five children mill around and his wife tends a pot over a wooden fire. He used to be a corn farmer, but then his eyes started itching three years ago.

Now, he is totally blind and cannot work. He does not know what happened, nor is he the only villager whose vision began to disappear. He said he went to a witchdoctor, but it did not help.

The man's blindness is not a result of magic, but a small worm that invaded his body. He is one of 37 million people worldwide, most of them in sub-Saharan Africa, suffering from onchocerciasis, commonly known as river blindness.

It is nearly impossible for many African villagers to avoid the disease, which is transmitted by black flies that breed in the clean, fast-moving water used for drinking, bathing and washing clothes. The flies are the vector for parasitic worms that are transmitted to humans through fly bites. The worms enter the body, nestling near bone protuberances, where they breed millions of offspring.

It is these small worms that cause the debilitating symptoms of the disease. The early stages produce incessant itching that makes it difficult to work and can cause people to lose sleep for years at a time. The latter stages can leave the victim blind.

The disease is curable — and the drugs are available for free — but it has still proven difficult to eradicate.

"Onchocerciasis is a forgotten disease," said Dr. Sungwa Ndagabewene, a medical officer in the Southern Highlands region of Tanzania whose one-story office is surrounded by flowers and roaming chickens. "It needs more attention and it is a disease which we can eliminate if we put more effort into it."

There is one effective medication available — ivermectin, manufactured by Merck — but it can be difficult to convince people to take it.

The drug does not kill the adult worms but reduces their breeding rate and kills off the belligerent offspring. When sufferers first take the drug, it can produce severe itching and swelling, as the baby worms inside the body die off.

The drug must be taken annually for the life of the adult worm, which is about 15 years. Further, everyone in the village must take the drug — with the exception of small children, the very ill and pregnant and nursing women — or else the worms will continue to breed and can reinfect the population.

Additionally, people frequently stop taking the drug once the symptoms of the disease subside, often after several years of treatment, said Tanzania’s minister of health and social welfare, David Mwakyusa.