Nuclear size and DNA content in host cells during first-generation schizogony of Eimeria zuernii

The response of intestinal host-cell nuclei of calves infected with Eimeria zuernii 6 and 8 days post-infection was examined using Feulgen-DNA microspectrophotometry. The results show that nuclear hypertrophy is dissociated from DNA replication. In the light of previous work (Fernando, Pasternak, Barrell & Stockdale, 1974) it is surmised that the specificity of infection of cells by E. zuernii is not stringent, with the major target being non-proliferative cells. At most, 20% of the first-generation schizonts develop within cells that would have had proliferative potential and as a result some non-scheduled DNA synthesis occurs.