Failure of chloroquine in human babesiosis (Babesia microti): case report and chemotherapeutic trials in hamsters.

The failure of a 3-week course of chloroquine to eliminate an infection of Babesia microti acquired on Martha's Vineyard led to tests of selected drugs in hamsters infected with the strain from this patient. The results showed response to several antitrypanosomal drugs (pentamidine and 4,4'-diazoaminobenzamidine) but not to antimalarial drugs (chloroquine, sulfadiazine, and pyrimethamine).