The Burning Zone

fever, headache, nausea, diarrhea, myalgias and malaise.
in 30 to 40% of acute cases, the spleen is enlarged and liver may be tender.
repiratory and renal failure, shock, acute encephalopathy, pulmonary and cerebral edema, coma and death may result from severe cases (especially Plasmodium falciparum infections).
duration of an untreated primary attack range from 1 week to 1 month or longer; relapses of febrile illness can occur at irregular intervals for up to 2 to 5 years.
chronically infected persons develop hyper-reactive malarial splenomegaly or nephrotic syndrome.
case fatality rates among untreated children and nonimmune adults exceed 10%.

Infectious agent

Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malariae.
protozoan parasites with an asexual cycle in humans and sexual cycle in mosquitos.

Mode of transmission

bite of an infective mosquito.
not directly transmitted from person to person.
transmission by transfusion and transplacental transmission account for a small percentage of infections.

Distribution

indigenous malaria persists in about 100 tropical and subtropical countries.
disease occurs in Africa, Asia, Mexico, Central and South America, the Caribbean, the South Pacific Islands and in parts of the Commonwealth of Independent States.
worldwide, an estimated 200 to 300 million infections occur annually, with 2 to 3 million deaths (most are from Plasmodium falciparum).
Chloroquine-resistant Plasmodium falciparum strains have been reported from endemic areas in Africa, Asia and the Americas; continued spread of resistence is expected.

Incubation period

10 to 30 days, depending on virus strain.
transmission by transfusion can occur as long as asexual forms of the parasite remain in the circulating blood (for Plasmodium malariae this can be more than 40 years).

Treament

Cholorquin is drug of choice unless resistant Plasmodium falciparum is suspected.
quinine plus tetracycline, pyramethamine and sulfadiazine/clindamycin or mefloquine should be used for resistant Plasmodium flaciparum strains.
resistance of Plasmodium falciparum malaria to all antimalarials has been reported; in these cases, combination therapy and repeated courses of treatment may be necessary.

Thanks to the World Health Organisation
for much of this information.

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