The pathology of subclinical infection of Encephalitozoon cuniculi in canine dams producing pups with overt encephalitozoonosis.

The macroscopic, microscopic and clinical pathology and the serology of 2 clinically normal Staffordshire Bull Terrier bitches, both of whom produced pups with confirmed encephalitozoonosis, is described. Mild histopathological changes, similar to those seen in the infected pups, were observed. The spores of Encephalitozoon cuniculi were seen in the renal tubules of the kidney of one of the bitches. The serum urea concentrations of one of the bitches was elevated. A positive titre against E. cuniculi was obtained in both of the bitches. A 10-year-old girl who had had close contact with one of the infected litters of pups, seroconverted to E. cuniculi. Her two siblings were serologically negative.