A 45-year old German hospital laboratory technician spent her holiday in Tanzania under malaria prophylaxis with chloroquin and proguanil. Seven months later she had a fever and a headache. A thick blood smear revealed Plasmodium falciparum. She was treated immediately with halofantrine, which led to the relief of symptoms and clearance of the parasites. Another 3 months later falciparum malaria developed again, and the patient was treated with mefloquine. She had her next bout of falciparum malaria 2 months later and received oral quinine and doxycycline therapy. Somewhat later, her fourth attack was treated with quinine and doxycycline intravenously under supervision.

When further episodes followed, her physicians became suspicious and undertook studies of the parasite. P. falciparum parasites from attacks 9 to 13 were investigated for in vitro sensitivity to chloroquine, quinine, and mefloquine and for the genotypic pattern of their merozoite surface antigen 1 (MSA-1) polymorphisms.

Parasites from attacks 10 and 12 showed a high susceptibility to quinine and mefloquine and resistance to chloroquine. Furthermore, the different lengths of polymerse-chain-reaction fragments from the MSA-1 gene clearly showed different parasite genotypes in attacks 9 through 13.

The circumstances of the case led the responsible physicians to interrogate the patient. A rather prompt confession uncoverd the mystery of the case. The patient, having access to infected blood from other patients, was infecting herself by repeated intravenous inoculations of amounts of as much as 1 ml of fresh parasitized blood from various donors. The patient is now receiving psychiatric treatment.

Kun, J.F.J., Kremsner, P.G., Kretschmer, H., Tübingen, Germany

N. Engl. J. Med., Letter to the Editor, 1997; 337:1636