Sporozoites of Eimeria acervulina within intestinal macrophages in normal experimental infections

Summary Sporozoites of Eimeria acervulina were observed in macrophages of the intestinal epithelium 5 and 6 days post-infection. These sporozoites lay within a well developed parasitophorous vacuole, were normal in structure and showed no signs of development. Macrophages harbouring sporozoites showed considerable structural changes, most pronounced being an absence of lysosomes, an enlarged nucleolus and extensive proliferation of the Golgi complex and endoplasmic reticulum. Possible mechanisms of survival and transport of sporozoites to preferred sites of development are discussed.Key to Lettering of Figures ER Endoplasmic reticulum - ERM Endoplasmic reticulum of macrophage - GOM Golgi zone of macrophage - INM Invaginations of macrophage cell membrane - LM Lipid globule of macrophage - LYM Lysosomes of macrophage - MI Mitochondria - MIM Mitochondria of macrophage - MN Micronemes - MP Micropore - N Nucleus - NM Nucleus of macrophage - PO Rhoptries (paired organelles) - PV Parasitophorous vacuole - RB Refractile body - V VacuoleThis study was carried out in the Department of Poultry Research, Wye College (University of London), Wye, Kent, while the author was a Wellcome Trust Research Fellow.