Simple focus assay for Encephalitozoon cuniculi. Lab Anim

In this in vitro infectivity assay for Encephalitozoon cuniculi, lesions due to the organism appeared as macroscopically distinct foci. The number of such foci was used as a direct measure of the number of infectious units in the original sample. The expected correlation between focus-forming units and 50% infectious doses was observed in limit dilution experiments. Encephalitozoon cuniculi (Microsporida, Glugeidae) is an intracellular protozoan parasite which frequently causes chronic infections in laboratory animals, especially rabbits (Canning, 1977). The organism can be grown in cell cultures derived from a number of species, including rabbits (Shadduck, 1969), dog