Summary
Sporozoites of Eimeria contorta inoculated into monolayer cultures of bovine embryonic kidney cells and Madin-Darby bovine kidney cells developed to mature second-generation schizonts, which were first seen 72 hr after inoculation. In cultures of bovine embryonic intestine cells, only mature first-generation schizonts developed. Intracellular sporozoites became U-shaped before transforming into trophozoites with a prominent refractile body. Sporozoite-shaped schizonts were not seen. At 30 hr after inoculation, merozoites began to form as conical protrusions of the surface of schizonts with 25–35 nuclei. Mature first-generation schizonts (25 by 20μ), with 25–35 merozoites each having two refractile bodies, were first observed at 46 hr. The merozoites averaged 9.5 by 2.0 μ. After enough sodium taurocholate to make a concentration of 0.01% was added to the cultures, merozoites left their host cells, entered others and transformed into trophozoites within 4 hr. Merozoite formation frequently began with the appearance of conical protrusions at opposite poles of second-generation schizonts. During the late stages of their development, the 8–15 merozoites were spirally arranged around the central residual body. Mature schizonts and merozoites averaged 19 by 8.5 μ and 22.5 by 1.4 μ, respectively. In some cultures, larger schizonts with 30–40 merozoites, arranged rectilinearly with respect to the residual body, were observed. On the basis of a comparison with the corresponding stages of E. nieschulzi, it is concluded that E. contorta is a valid species.
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This investigation was supported by PHS Research Grant No. AI-07488 from the National Institute of Allergy and Infectious Diseases and by a fellowship awarded to B. E. G. Müller by the German National Fellowship Foundation. Published as Journal Paper No. 1339, Utah Agricultural Experiment Station.
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Müller, B.E.G., Hammond, D.M. & Scholtyseck, E. In vitro development of first- and second-generation schizonts of Eimeria contorta haberkorn, 1971 (coccidia, sporozoa). Z. Parasitenk. 41, 173–185 (1973). https://doi.org/10.1007/BF00329485
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DOI: https://doi.org/10.1007/BF00329485