July 1, 2009

Common Pet Drug May Eradicate River Blindness: WHO

The World Health Organization said Wednesday that a drug commonly used to treat pets with parasites may offer hope in eradicating river blindness.

Moxidectin, prescribed for dogs, cats, cattle and horses to treat parasites, shows potential to destroy the worms that cause river blindness, an infectious disease that threatens 100 million people, the U.N. agency said.  The condition, whose formal name is onchocerciasis, comes with debilitating symptoms such as loss of sight, severe rashes and lesions.

"If moxidectin kills not only the larvae but also sterilizes or kills the adult worms, it has the potential to interrupt the disease transmission cycle within around six annual rounds of treatment," the WHO said in a statement.

The announcement of clinical trials for the drug coincides with renewed  hopes that river blindness can be entirely wiped out rather than just controlled.

The WHO declared the eradication of smallpox in 1980 after its initiative to wipe out the disease that began in 1970.  The U.N. agency  has been working for more than three decades to halt the transmission of polio, which remains endemic in Afghanistan, Pakistan, India and Nigeria.

But river blindness has particular meaning.  The WHO initially launched an eradication campaign in 1970 using insecticide to destroy the blackflies that transmit the disease-causing worm larvae.   Although the campaign came close to succeeding, it was ultimately unable to eradicate the disease, which is portrayed in a statue outside the agency's headquarters in Geneva of a young boy leading an elderly blind man with a stick.

The initiative to wipe out river blindness later shifted goals, seeking to merely control the effects of the disease through the use of Merck's drug ivermectin.

But Wyeth has now reformulated Moxidectin, used in Bayer Animal Health's anti-flea treatments for pets, for use in humans.

The drug will now be tested for use in preventing and treating river blindness, according to a Reuters report citing Wyeth Pharmaceuticals vice president Henriette Ukwu.

Clinical trials are set to take place in Liberia, Ghana and the Democratic Republic of Congo over the next few years.

Ukwu said the company was providing the drugs at  no cost for the trial, and planned to seek regulatory approval for wider distribution if the trial is successful.

"There is no commercial interest for this product," she said, adding that Wyeth would work to ensure the drug is available through existing aid channels.


Image Caption: Adult Black Fly (Simulium yahense) with parasite (Onchocerca volvulus) emerging from the insect's antenna. Magnified 100x. Courtesy Agricultural Research Service


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