The presence of atypical lymphocytes in the peripheral blood smear is usually associated with a variety of viral illnesses. Although not all viral infections are associated with atypical lymphocytes, the presence of atypical lymphocytes has also been associated with a variety of nonviral infections, such as toxoplasmosis, babesiosis, and malaria. In the appropriate clinical context, the presence of atypical lymphocytes may be an important laboratory diagnostic clue to the presence of some nonviral diseases, such as malaria drug fever.1,2
Traditionally, hematologic findings in cases of acute malaria include intravascular hemolysis and thrombocytopenia. Atypical lymphocytosis has been reported in some cases of malaria.3-5 However, the incidence of atypical lymphocytosis in cases of malaria has not been determined and has not been related to the infecting species or the degree of parasitemia.
Accordingly, we reviewed our 5-year experience with proven cases of acute malaria to determine the incidence of atypical