No known chemotherapeutic agents are known to be effective although chloroquin phosphate and primoquin phosphate used in combination has been proposed. This is a intracellular microsporidian parasite found in cytoplasmic vacuoles of renal tubular epithelial cells, endothelial cells, tissue macrophages and hepatocytes. Once thought to be similar to Toxoplasma, it is now recognized that members of this genus lack an apical complex and posess microsporidian polar tubes and capsules. Natural infections are reported from domestic and wild canines, rodents, felines, and other wild carnivores. Although the life cycle in nature is not totally known, canine encephalitozoonosis is a kennel problem when large numbers of animals are confined under less than desirable sanitary conditions.
Clinical signs depend on the time, course, and location of tissue damage.
In neonates, clinical signs appear a few weeks postpartum, showing stunted growth and unthriftiness. As the course of infection progresses, animals show renal failure and neurologic signs such as depression, ataxia, convulsions and blindness. Animals may develop signs of aggressive behavior. Clinical signs in cats vary from asymptomatic to severe muscle spasms, depression, paralysis and death. Clinical laboratory findings are non-specific being usually a normochromic, normocytic anemia consistent with severe renal lesions with depression of erythropietin production.