Abstract
Twelve cases of an unusual phenomenon of ataxia were investigated in otherwise well, conscious patients recovering from a febrile attack of presumed falciparum malaria. The ataxia occurred as the fever was subsiding, usually after an afebrile period of two to four days. The delay between onset of fever and the ataxia was three to four weeks. Peripheral blood of all the patients contained gametocytes of Plasmodium falciparum, and in some cases ring stages. The ataxia was most noticeable in the legs and the clinical picture suggested selective impairment of the cerebellar system. Signs of improvement appeared in a few weeks but complete recovery took one to four months. The most likely pathogenic mechanism of the ataxia in these cases was an immune reaction triggered by the malaria parasite and affecting the cerebellum or its connections, or both.