The Life Cycle and Incidence of Hepatozoon balfouri (Laveran, 1905) in Egyptian Jerboas ( Jaculus spp.) and Mites ( Haemolaelaps aegyptius Keegan, 1956) *

The incidence of Hepatozoon balfouri (Laveran, 1905) in examined populations of Egyptian jerboas was 41% in Jaculus j. jaculus , 21% in Jaculus o. orientalis , and nil in Allactaga tetradactyla . Infection in a few animals apparently less than 6 days old suggests the possibility of transplacental transmission. The cycle in erythrocytes and parenchyma cells of the liver is described; stages in liver are seldom seen in chronic infections. Blood of many other Egyptian rodents and insectivores was negative for H. balfouri . The sporogonic cycle in mites, Haemolaelaps aegyptius Keegan, 1956, fed on infected jerboas, resembles that of other typical Hepatozoon species. Sporocysts contain 6 to 16 (usually 12) sporozoites. Infection rates in experimental cultures of H. aegyptius varied greatly. Mites from only a single graphic area could be experimentally infected; in the same area, the infection rate in J. jaculus is significantly higher than elsewhere. Biological races of Haemolaelaps aegyptius , more or less refractive to H. balfouri infection, may exist. Large numbers of mites, lice, fleas, and ticks removed from infected jerboas were uninfected, as were numerous arthropods experimentally fed on infected jerboas. Owing to the presence of H. balfouri foci in widely differing ecological zones of North Africa and Sudan, different species of mites, and possibly of other arthropods, obviously transmit the infection; details of this likelihood require further investigation.