The order Eucoccidiorida is divided into two suborders. These two groups differ in their sexual development: syzygy for Adeleorina and independent gametes for Eimeriorina.
The ﬁrst suborder, Adeleorina, comprises coccidia of invertebrates and the coccidia that alternate between blood-sucking invertebrates and various vertebrates; this group includes Haemogregarina and Hepatozoon. There are seven families in this suborder.
The second suborder, Eimeriorina, comprises coccidia of a variety of coccidia many of form cysts. A number of genera, including Toxoplasma and Sarcocystis, infect vertebrates.
Lillehoj, Hyun S. (October 1996). "Two Strategies for Protecting Poultry From Coccidia". Agricultural Research magazine (United States Department of Agriculture: Agricultural Research Service) (October 1996). Describes using live-parasite vaccine versus a monoclonal antibody to block the sporozoite from invading a host's cell.