Infectious Diseases: More Action, More Malaria

“Next to girls,” says Colonel Spurgeon Neel Jr., chief medical officer of the U.S. Military Assistance Command in Viet Nam, “the thing that American troops in Viet Nam talk about most is malaria.” The malaria casualty count has been rising sharply as U.S. forces expand their efforts in the very parts of the country where the disease is rampant (TIME, Aug. 20).

Through the first nine months of this year, the malaria attack rate among U.S. forces was only 30 per 1,000 men per year (as contrasted with the World

War II high of 160). A total of 213 cases was reported; of those, only six were of the “benign tertian” or vivax type. All other cases were caused by the far more virulent parasite, Plasmodium falciparum, which sets off violent fevers and may make a fatal attack on the brain, spleen or other organs.

V.C.s’ Mutual Aid. The mosquito-borne malaria parasite of Viet Nam jungles shares its territory with the Viet Cong. In fact, they support each other. The Viet Cong have given the disease a free hand by preventing anti-mosquito spraying. And malaria has helped the V.C. by attacking newly arrived U.S troops who do not share the partial immunity of men who have had malaria and recovered. It has become a truism among U.S. troops that “if you go out and catch Viet Cong, you’ll also catch malaria.”

More than 500 did just that in the month of October, and the total for November will probably be much higher. Hundreds of victims have already been evacuated to military hospitals around the Pacific because the armed forces routinely evacuate any man who is not expected to be able to return to duty within 30 days, and falciparum-malaria treatment and convalescence take from five to eight weeks.

Back to Quinine. Medically, the most disturbing aspect of malaria in Viet Nam is the appearance of falciparum parasites that are resistant to chloroquine, which was hailed only a few years ago as the almost perfect antimalarial drug. U.S. servicemen take a weekly prophylactic tablet containing 300 mg. of chloroquine and 45 mg. of another antimalarial known as primaquine. If they develop malaria despite this, they are likely to be infected by a resistant strain of parasites. If massive doses of chloroquine fail to bring the fever down within a few hours, the medics may switch to pyrimethamine (Daraprim), which is effective in some of the less severe cases. In most instances, however, the medics are forced back to quinine, the oldest antimalarial of all. For pernicious malaria threatening the brain, quinine must be given intravenously in heavy doses, which may in itself cause death.

Despite strict malaria discipline, the Department of Defense reports that ten Americans have died in Viet Nam this year from cerebral or other complications, and researchers are intensifying the hunt for new drugs. One that shows some promise is DOS (diaphenylsulfone), normally used in leprosy. Another is a new, long-acting sulfa drug, Fanasil. Malariologists are running tests with prison volunteers to see whether DDS or Fanasil can be used, probably in combination with pyrimethamine, to beat back the chloroquine resistance of falciparum parasites in much of Southeast Asia.