Plasmodium ovale Malaria in Travelers and Immigrants to the United States: A Case Series

Malaria in child travelers caused by Plasmodium ovale spp. is less well characterized than malaria due to other Plasmodium species. Commonly used diagnostic tests often lack adequate sensitivity to identify P. ovale spp., and a missed diagnosis may have serious consequences. We present a case series of eight children in the United States with P. ovale malaria, all of whom had traveled to or immigrated from malaria-endemic areas. Two children developed clinical malaria, including one with severe malaria; two had isolated splenomegaly; and four were asymptomatic siblings of the children with splenomegaly. Seven of the eight children had negative blood smear readings, and the diagnosis was made by polymerase chain reaction testing. Two children had concurrent P. malariae infection despite presumptive antimalarial treatment before immigration. These findings suggest a need for reconsideration of screening and diagnostic evaluation for P. ovale malaria in high-risk groups.