Medicine: Malaria on the March

Of all the diseases that plague man, one of the most resilient is malaria. As recently as a dozen years ago, health authorities believed they had the disease on the run in South Asia, where throughout history it had taken its greatest toll. Now the World Health Organization admits that its victory bulletins were premature. Malaria has returned to the region−with a vengeance. The total number of victims in South Asia this year is expected to reach 20 million.

All of Asia's southern tier, from Afghanistan to Indonesia, is affected by the outbreak. But...