The Hemococcidia of Lizards
The Hemococcidia, family Lankesterellidae Nöller 1920, represented in reptiles by three genera, Lankesterella Labbé 1899, Schellackia Reichenow 1919, and Lainsonia Landau 1973, are true coccidians, related to the intestinal parasites of the Eimeriidae. The course of gametogony and sporogony within cells of the intestinal wall in lizards differs little from the intestinal coccidians except in the absence of sporocyst formation in the lankesterellids. Instead of transmission by direct contact with sporocysts in a fecally contaminated external environment, sporozoites enter circulating blood cells (leukocytic, erythrocytic, or both, depending on the species) and then are ingested by acarine or dipteran vectors. Transmission is accomplished at least for saurian hosts by predation on the infected invertebrate. There is no development or multiplication within the vector; it plays a mechanical role only in the hemococcidian life history. Infections by hemococcidia can be transmitted experimentally by ingestion of the infected arthropod or by intraperitoneal injection of infected blood (Bonorris and Ball, 1955; Landau et al., 1974; Lainson et al., 1976; Bristovetsky and Paperna, 1990; Paperna and Finkelman, 1996). Jordan and Friend (1971), Klein et al. (1988a), and Bristovetzky and Paperna (1990) transmitted Schellackia infections by feeding infected mites, ticks, mosquitoes, or sand flies to lizards. Bristovetsky and Paperna (1990) and Finkelman and Paperna (1998) fed infected blood and liver to uninfected lizards and accomplished transmission to the recipients.