Direct infection of hepatocytes by sporozoites of Plasmodium berghei.

To identify the unknown liver cell type initially invaded by sporozoites of mammalian malaria, young rats were inoculated intravenously with large numbers of Plasmodium berghei sporozoites obtained from infected Anopheles stephensi mosquitoes. Fine structural studies of liver specimens obtained from the rats within 2 min after inoculation demonstrated the presence of morphologically unaltered sporozoites in the cytoplasm of hepatocytes. Many sporozoites were also observed undergoing cytolysis within the lysophagosomes of Kupffer cells, as well as other phagocytic cells. These observations strongly suggest direct infection of the hepatocyte by the sporozoite.