River Blindness is a parasitic infection that afflicts 37 million people worldwide. People catch this infection when bitten by black flies that carry a nematode known as Onchocerca volvulus. The worm larvae mature and mate, producing up to 1000 offspring per day, which migrate to the surface of the skin and to the eyes. When the offspring die, they cause itchy lesions that can lead to blindness. The effects are severe, but according to the February 9th 2010 issue of Science, a veterinary drug that kills worms in cattle may also fight this infection.
Doctors previously treat river blindness with ivermectin, a drug that kills the offspring and lowers the fertility of the adult worms. The drug works fairly well, but doesn’t target the nearly-mature worms that cause new infections from a black fly’s bite. Instead the drug controls the symptoms until the worms eventually die out. Researchers stumbled upon the veterinary drug closantel, which kills live parasites in cattle. The enzyme in this drug, known as chitnase, breaks down and rebuilds the O. volvulus larvae's outer casing during the final molt before adulthood. If closantel has the same effect in humans, it could prevent infections from starting. And because it works in a completely different way from ivermectin, any strains of O. volvulus that show resistance to ivermectin in the future could be treated with closantel.
Many researchers are optimistic about working with closantel because it has already proven safe in farm animals. However, it binds strongly to a protein found in the blood, which could lead to side effects in humans. The research on closantel is still being worked on, but if it does prove successful it could end up helping a lot of people through out the world.
Posted by Ryan Brooks
Wednesday, March 10, 2010
Cattle Drug May Help Tackle River Blindness
Posted by Peter Houlihan at 7:48 PM
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That would be great if it was made to be able to work in humans without side effects. It still seems a long ways off from being properly tested in humans or even being made into a drug though. It also needs to be made sure that it can fight against the disease in between doses. If it can though it certainly will be helpful, as you said, for it to be used alongside ivermectine and decrease the chances for the disease to build up an immunity for either treatment.ReplyDelete
Posted by Daniel Solomon
I think it is always really neat when experts find other uses for drugs that are used for completely different reasons. I wonder how many drugs out there can be the treatment or cure we are looking for. It would be a wonderful thing if this would work to treat this and it's good that the researchers are optimistic about this. Only time will tell how humans are affected by this and how they respond to the treatment. It could turn out beneficial but there are always risks in things like this.ReplyDelete
Post by Amanda Makowski
Closantel show some promising results but is still far from being approved. The enzyme still isn’t approved for use in all animals in all countries, including the United States. Scientists also have to prove closantel lasts long enough to provide protection between intermittent doses. One of the reasons why ivermectin works so well is that it only has to be taken once or twice a year. Although closantel shows some promising results, it still has to undergo more research before being approved for use in humans.ReplyDelete
Posted by Ryan Brooks