Your recent article on malaria ("Malaria prevention," Issue No. 90) has a few errors and omissions that this retired preventive medicine type noted. First, permethrin is more toxic than DEET, not less. It is actually an insecticide (of the pyrethroid class), not just a repellent, with some uses for killing lice. Uncle Sam’s Army says never put it on the skin, just on the outer clothing. It does have the advantage that it is still effective after several washings.
Also, way back when, we named WR-142,490 "mefloquine," with a terminal "e." On a more serious note, if you are going to take malarial prophylaxis, you must start taking it some time before you enter the malarious area (to build up an effective blood level). And you have to continue taking it for some time after you leave (to kill off any plasmodia you may have picked up). How long you take it depends on the drug, but the CDC can give you the current word. In addition, for more than a year after you get off the drug, you can develop a case of somewhat drug-resistant malaria that the prophylactic did not quite kill off. (In fact, the day after I got your magazine, I got a new issue of Military Medicine magazine with an article on a soldier at Fort Lewis, Wash., who came down with vivax malaria some 13 months after leaving the infected areanear the Demilitarized Zone in Korea. He wasn’t diagnosed until his second attack, which was a month after the first bout of the disease.
Therefore, if you have been in a malarious area within the last two to three years and you develop a fever, be sure to tell your physician about your travels so he or she can check for malaria and treat it properly.