Each year malaria infects up to 500 million people worldwide. More than a million succumb to the deadly disease, most of them children. For years the medical community combated the disease with chloroquine--a cheap, effective drug that did much to alleviate the situation. But chloroquine-resistant malaria emerged and spread over the next few decades. Today resistant strains flourish in Asia, Africa and South America. Research reported in the October 20 issue of the journal Molecular Cell, however, may eventually change that. According to the new study, scientists have identified the gene that makes the malaria parasite resistant to chloroquine. The finding could facilitate efforts to develop drugs to treat the disease. Furthermore, it could allow for the return of chloroquine itself.

Because the malaria parasite took a relatively long time to develop chloroquine resistance, investigators had suspected that many genes were involved. But Thomas Wellems of the National Insitute of Allergies and Infectious Disease and his colleagues found that, in fact, only between four and eight mutations in a single gene dubbed pfcrt determine whether the parasite line is resistant or not. Considering that, the team believes it might be able to tweak the chloroquine composition so that it will work against the parasite once more.

In related news, the latest updates on other antimalarial tactics are described in the October 20 issue of the journal Science. The outlook is encouraging: within five to 10 years scientists think they will have a successful malaria vaccine. And before that a Chinese herbal remedy known as artesunate may be made available. Yet as new resistant strains arise, positive results can't come soon enough.