Which coccidia cause intestinal symptoms in dogs and cats?
The pathogenicity of the coccidia (the ability of the coccidian species to cause disease symptoms) depends on many factors including: 1) the number of oocysts eaten – large numbers of oocysts ingested at any one time can cause rapid-onset, severe disease. 2) how rapidly the organisms divide – the faster the coccidian organisms divide asexually, the quicker the host cells are destroyed and more cells become invaded. 3) the size of the replicating cysts (tachyzoites) – larger cysts release greater numbers of infectious merozoites into the intestine to invade more cells and create more damage. 4) the number of replication cycles needed – coccidia with higher numbers of tachyzoite replication cycles are able to invade more cells and create more damage before they are forced to become dormant in their bradyzoite forms or convert into sexual, oocyst-making forms. Coccidia with higher replication cycles may, however, experience a greater delay before the infectious oocysts will appear in the
