River blindness is a major problem in Asia and Africa, being the leading cause of blindness in many parts of the developing world. New research recently published in Science, however, suggests the disease may be controllable by cheap antibiotics.
River blindness is caused by a small worm, Onchocerca volvulus, which burrows under the skin and then releases hundreds of offspring which spread throughout the body. IT causes a number of problems, with the most severe being an inflammation in the eyes that eventually causes blindness.
Researchers studying the worm’s effect on mice, however, made an important discovery about a bacteria that the worm relies upon. The bacteria, wolbachia, appears necessary for the worm to reproduce and it turns out it is the bacteria — not the worm — which causes the blindness.
In tests on a mice model of the disease, researchers at the Institute for Tropical Medicine in Hamburg, Germany, infected two groups of mice with different forms of the worm. The control group was infected with normal worms, while experimental group of mice were infected with worms that had been treated with antibiotics.
The mice infected with the treated worms experienced significantly less inflammation and vision problems than did the control group. The mice model revealed that there is a receptor in the eye that appears to be particularly sensitive to the bacteria, which leads to the blindness-causing inflammation.
British tropical medicine research Mark Taylor told the BBC that the research would revolutionize the treatment of river blindness,
This research has totally changed our understanding of the disease and opens up new options for its treatment. Even in a mud hut medical center, you will find the antibiotics, which are effective and sterilizing the worm and clearing the bacteria. The hope is that this new approach will both clear the pathogenic bacteria from existing worms and, through sterilization, prevent the release of new worms, so preventing the onset of disease and recurring infection.
In other words, after being exposed to the worm, some regimen of antibiotics could be used to ensure that the initial exposure does not result in a deluge of hundreds of worms and the subsequent potential for causing blindness.
Further research is underway to confirm the results and find the most effective methods of using the antibiotics to control river blindness.
Source:
Bacteria cause river blindness. Tom Clarke, Nature, March 8, 2002.
Bacteria ‘holds key’ to river blindness. The BBC, March 7, 2002