HEALTH: Tests Underway for Effective Remedy to Combat River Blindness

By Marwaan Macan-Markar Reprint | | Print |

Marwaan Macan-Markar

MEXICO CITY, Jun 18 2000 (IPS) - Close to 36 countries in the developing world stand to benefit from tests that have begun in Ghana with an available antibiotic billed as a remedy to cure river blindness.

Such tests in that West African nation follow the announcement this month by a team of scientists from Britain, Cameroon and Germany that they have discovered an effective way of combating the disease, the world’s second leading infectious cause of blindness.

This revelation, which appeared in the latest issue of a British publication, the “Royal Society’s Proceedings: Biological Sciences,” states that research conducted on cows to combat the parasitic worm that causes river blindness could be as effective in wiping out the infection in humans.

During their research, the international team of scientists had used an available antibiotic, Tetracycline, which had killed the bacteria living in the parasitic worm, known as Onchocerca volvulus.

“This observation is important,” says Dr. Janis Lazdins, the co- ordinator of the Filariasis Research and Development Programme at the World Health Organisation (WHO).

But he adds that it is still too early to feel optimistic about this development. “The key issue is that of determining if the effect can be reproduced in humans and if we can use other antibiotics.”

And the tests that have begun on people in Ghana are expected to provide clues to that. According to the scientists, an answer will be available within two years.

If successful, this will offer “a cheap, safe and effective way of curing the infection,” declared Professor Alexander Trees, a member of the research team, to the British media.

Currently, about 18 million people are infected with the disease, 99 percent of whom are in Africa, and some 120 million people worldwide are at risk of becoming victims of it, states the WHO. Of the 36 countries where the disease is endemic, 30 are in Sub-Saharan Africa and six are in the Americas.

If not treated well, this disease, known in medical terms as onchocerciasis, often evolves towards total blindness and serious skin diseases. And the consequence of that is “a significant negative economic impact,” asserts Dr. Lazdins.

Researchers have been trying to rid the world of the disease for 26 years. In 1974, the first major initiative to tackle it was launched in seven West African countries under a plan called the Onchocerciasis Control Programme (OCP).

Initially, the method pursued under the OCP was aerial insecticide spraying of rivers to kill the larvae of the blackfly that transmits the disease. Subsequently, a drug was also distributed to the communities where the disease prevailed, helping to kill the larval worms that caused blindness.

And the results reveal a wide-spread success rate. “Some 1.5 million people who were once infected with onchocerciasis no longer have any trace of the disease,” the WHO points out, adding further that the 11 million children born in the areas where the OCP was implemented are “now free of risk of contracting the disease.”

Furthermore, by the end of the last century it was estimated that the OCP had prevented almost 300,000 cases of blindness in the 11 countries participating in the programme.

Unfortunately, says Dr. Lazdins, the drug used in this effort, Mectizan, does not kill the adult parasitic worms, which can live up to 14 years in the human body. Consequently, the victims have to be treated for 10 to 15 years.

That, however, is not the case with Tetracycline, since it has the potential of killing the adult worms. Such a prospect, he adds, would “obviously help and facilitate the control programmes.”

The current tests in Ghana with Tetracycline are bound to come under close scrutiny because they are being conducted at a time when medical experts have begun to question the effectiveness of antibiotic drugs.

Last week, in fact, the WHO revealed in a report that virtually all the world’s infectious diseases are becoming resistant to existing medicines. “The effect of anti-microbial resistance is that it can reduce the curative power of once life-saving medicines to that of a sugar pill,” added the 67-page report, “Overcoming Microbial Resistance.”

According to David Heymann, the WHO’s executive director for Communicable Diseases, “We are literally in a race against time to bring levels of infectious diseases down worldwide before the diseases wear the drugs down.”

To date, says Gregory Hartl, spokesman for the WHO, only one disease has been eradicated – smallpox, in 1980-while two others, polio and leprosy, are on the verge of being wiped out.

That does not mean, however, that one should give up hope regards the Tetracycline trials in Ghana, contends Dr. Lazdins. In his view, any research that addresses “our ‘neglected diseases’ is a key to provide hope, it (will) encourage the experts in product development towards producing new therapeutic approaches.”