New drug resistance found in river blindness

Jun 15, 2007

A 20-year effort to control the spread of onchocerciasis, or river blindness, in African communities is threatened by the development of drug resistance in the parasite that causes the disease, a study by McGill University researchers has found.

“We’ve found the first evidence of resistance, where the adult parasites continue to reproduce and transmit the disease, and in some communities it seems to be getting worse,” said Dr. Roger Prichard, James McGill Professor in the University’s Institute of Parasitology, whose findings appear in the June 16 edition of The Lancet.

River blindness, which is the second-leading infectious cause of blindness worldwide after trachoma, is caused by the filarial nematode parasite, a worm transmitted by black fly bite. It leads to visual impairment, blindness, and, in some cases, pathological changes in the skin. Adult worms can survive as long as 10 to 15 years in a human host, releasing millions of tiny worms (microfilariae) each year. An estimated 37 million people are infected worldwide, primarily in Sub-Saharan Africa but also in parts of Central and South America and, to a lesser extent, the Middle East.

“This finding has important implications for this disease re-emerging and becoming a serious scourge,” said Dr. Prichard, warning that health organizations need to begin closely monitoring for the spread of drug resistance and new drugs need to be developed.

Dr. Prichard and his colleagues studied 2,501 infected people from 20 communities in Ghana, West Africa. Of those communities, 19 had been receiving annual doses of ivermectin, the only widely available drug used to treat onchocerciasis.

Although ivermectin wiped out the microfilarial stage of the parasite in 99 per cent of those treated, four communities experienced significant repopulation and in two communities, the prevalence of the parasite had doubled between 2000 and 2005, the researchers found. Two McGill graduate students, Mike Y Osei-Atweneboana and Jeff K.L. Eng, conducted the bulk of the research in collaboration with research institutions and health authorities in Ghana.

If left unchecked, Dr. Prichard warned, drug resistance could spread to communities where ivermectin treatment has successfully controlled the disease since the drug was introduced in the late 1980s, when, in an unprecedented move, Merck announced that it would provide the drug at no cost for as long as necessary.

Source: McGill University

Explore further: Cambodia bans 'virgin surgery' adverts

add to favorites email to friend print save as pdf

Related Stories

Bacteria coordinate activities with chemical 'language'

Jan 15, 2015

Ludwig Maximilian University of Munich researchers have discovered a previously unknown chemical language used by many bacterial species to coordinate their activities, and show in a model organism that such ...

Questioning GMOs

Nov 07, 2014

Are genetically engineered foods safe? Truth is, we probably don't know. "The scientific debate is not resolved, even though many people are claiming it is," says Sheldon Krimsky, the Lenore Stern Professor ...

Recommended for you

Why aren't there any human doctors in Star Wars?

12 hours ago

Though set "a long time ago in a galaxy far, far away," it isn't hard to see in the Star Wars films a vision of our own not so distant future. But Anthony Jones, a physician with a long background in health ...

Cambodia bans 'virgin surgery' adverts

Jan 29, 2015

The Cambodian government has ordered a hospital to stop advertising so-called virginity restoration procedures, saying it harms the "morality" of society.

What's happening with your donated specimen?

Jan 28, 2015

When donating blood, plasma, human tissue or any other bodily sample for medical research, most people might not think about how it's being used. But if you were told, would you care?

Amgen tops Street 4Q forecasts

Jan 27, 2015

Amgen Inc. cruised to a 27 percent jump in fourth-quarter profit and beat Wall Street expectations, due to higher sales of nearly all its medicines, tight cost controls and a tax benefit.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.