Scientists say they may have made a major breakthrough in the battle against river blindness, a disease affecting 17 million people.

Antibiotics could provide a cheap, safe and effective way of wiping out the disease, which is caused by a parasitic worm.

Scientists from the United Kingdom, Cameroon and Germany, say their experiments show that using antibiotics to kill bacteria living on the parasite, also kills the parasite itself.

This is an important step in finding a cheap, safe and effective way of curing the infection

Professor Alexander Trees, Liverpool School of Tropical Medicine

River blindness, or Onchocerciasis, causes severe itching, disfiguring lesions and lesions of the eye that can cause blindness.

It is most prevalent in sub-Saharan Africa, though the World Health Organisation says it will have stamped out the disease in West Africa by 2002.

The parasite is spread by blackflies which breed in rivers and deposit the larvae of the worm onto the person they bite.

There is currently no safe drug to fully treat the disease as available treatments only kill the young Onchocerca volvulus worms and not the adults.

The drug Mectazin has been used effectively, but has to be taken over 15 years and does not kill the adult worm.

Small doses of antibiotics would vastly reduce the length of treatment.

Killing bacteria

Professor Alexander Trees and his team from the Liverpool School of Tropical Medicine and the University of Liverpool's faculty of veterinary science, found that killing bacteria which are abundant in the worm tissues leads to its death.

They discovered that the most closely related parasite to the Onchocerca volvulus worm - the O. ochengi nematode - died after the bacteria living in it were killed by an ordinary antibiotic treatment of tetracycline.

Professor Trees said: "This is an important step in finding a cheap, safe and effective way of curing the infection. It is the first demonstration that a drug will kill the adult worm."

Paula Seager, of Sight Savers International, said: "It is going to be great news if we can speed up the treatment."

The research, published in the Royal Society's Proceedings: Biological Sciences, was carried out on cows, but the authors claimed similar antibiotic treatments could be just as effective in eliminating the infection in humans.

Trials are now underway on humans in Ghana and a treatment may be available within two years.