Parasitic protozoa are a major cause of global infectious disease. These eukaryotic pathogens have evolved with the vertebrate immune system and typically produce long-lasting chronic infections.

The Wood-Feeding Roach Cryptocercus, Its Protozoa, and the Symbiosis Between Protozoa and Roach L. R. Cleveland , S. R. Hall , Elizabeth P. Sanders , Jane Collier Memoirs of the American Academy of ...

A first time survey of free-living protozoa in meat-cutting plants showed high diversity rates of various species including those that could harbor food-borne pathogens say researchers from Belgium.