The Protozoa are known as apicomplexans and are members of the phylum Apicomplexa. The Apicomplexa include the coccidia, plasmodia, piroplasms. Still other organisms lumped into this group are miscellaneous parasites that include the Amoeba, Ciliates, Microsporidia, Sporozoa.
Many of these miscellaneous parasites are difficult to detect / diagnose simply because the symptoms overlap more common parasitic infections; are difficult to visually identify; require special methods for their detection; and are so uncommon that molecular and special testing at reference laboratories is needed.
Parasitology World 