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Essays > Malaria (October 19, 1999 by Pat Heyman)
The twilight was pleasant. A few mosquitoes whined about them. One settled on May-may’s ankle but she did not notice it. The mosquito drank its fill, then flew away. –Tai-Pan, James Clavell (1966)
The World Health Organization (1996) guidelines for preventing malaria are quite clear:
Avoid getting bitten!
Avoid getting bitten!!
Avoid getting bitten!!!
More specifically:
Prevent mosquitoes from biting people:
- Sleep under nets, preferably treated with insect repellent
- Screen all windows and doors
- Apply repellents to skin
- Burn mosquito coils
Control mosquito breeding:
- Eliminate places where mosquitoes can lay eggs
- Reclaim land by filling and draining
- Introduce fish that eat mosquito larvae
- Put insecticides in water that kill larvae
Kill adult mosquitoes
- Spray room with insecticide before going to bed
- Participate in activities carried out by the health services such as urban or village mosquito spraying. (WHO, 1996)
Not all of these strategies may apply to Americans living in America, but to the American traveler, some of them are extremely useful:
- Use repellent on skin
- Wear long sleeve clothing at night
- Use an insecticide in sleeping quarters
- Sleep under a mosquito net
Americans living in America can lobby for increased awareness and particularly urban control of insects and mosquitoes. (Gainesville has an urban mosquito control program; I have personally seen their trucks spraying within the past two weeks.)
Finally, remember that even though the Anopheles mosquito only bites at night, there are other disease bearing mosquitoes that do bite during the day, so mosquito-bite prevention should not simply be nocturnal matter.
Chemical Prophylaxis:
Chemical prophylaxis has long been used as a method to control malaria. Unfortunately, the prophylaxes are also malaria treatments, and their widespread improper use has given rise to resistant strains of Plasmodium. In Brazil and Southeast Asia, there are strains of plasmodium that are resistant to all known prophylaxis. Unfortunately, this means that they are also resistant to all known treatments as well. Further, prophylaxis can sometimes mask infections so that they are not recognized (can occur in travelers), thus promoting a false sense of security. Many of the chemical prophylaxes have serious side effects. Thus they should be carefully considered for the traveler going to malarial areas. The wrong choice could prove to be a costly mistake.
Immunizations
There is no vaccine for malaria. The complex lifecycle coupled with fast mutation make developing a vaccine extremely difficult. There are three possibilities. Attack the sporozoite stage (infection); attack the merozoite stage (disease process); attack the gametocyte (transmission). So far no vaccine has been able to successfully address any of these points in the Plasmodium lifecycle, much less all three. It is doubtful as to whether there will ever be a vaccine against malaria (Krogstad, 1996).
Etiology
Pathogenesis
Morphology
Clinical Manifestations