药片为对抗雅司病带来新希望

Scientists have found that a medicine taken in pill form is just as effective in treating the neglected tropical disease yaws as the usual treatment, a shot of penicillin.

The easier-to-use therapy raises new hope for the eradication of the disease.

Yaws is a disease affecting mostly poor children in the tropics. It eats away at skin, cartilage, and bone, affecting an estimated half-million youngsters in Africa, Asia, and South America.

The standard treatment is penicillin, which can be very effective, and an international program nearly eradicated the disease in the 1950s and '60s. But in recent years yaws has reemerged, in part because many infected children don't show any symptoms, and so don't get penicillin.

"For every one case of active yaws that we see, the estimates are that there's up to eight cases of children infected with the yaws organism who don't present because they don't have symptoms at the time," says researcher Russell Hays, a physician at the remote Lihir Medical Center in Papua New Guinea. "And so for that reason, just treating active cases when they come up will never eliminate the disease."

Hays and his colleagues wanted to see if another antibiotic would work as well against yaws, one that would be easier to use in a mass-treatment program.

While penicillin is effective, it also has its downsides: it requires syringes and trained health workers to inject the drug, the needles must be properly disposed of to prevent possible transmission of other disease, and there is a risk of an allergic reaction.

In a study of about 250 children, half got penicillin injections, the others got azithromycin in pill form.

After six months, the results were similar for each group: nearly all children were cured in both groups, and no serious side effects were reported.

But Hays, whose research appears in The Lancet, says this alone isn't enough to switch to the azithromycin pills.

"From our point of view, we feel that the next logical step is to conduct a mass drug administration of azithromycin in a limited setting, and to then follow up that population and see if we can demonstrate that yaws can be eliminated from a particular location."

In a commentary, also in The Lancet, tropical disease expert David Mabey, of the London School of Tropical Medicine and Hygiene, agrees with the need for more research. But he also worries that the yaws bacteria might develop resistance to azithromycin.