title: Experimental encephalitozoonosis in neonatal dogs.
abstract: The in vivo infection of neonatal dogs by the microsporidian protozoan parasite, Encephalitozoon cuniculi, was studied. Microscopic examination of tissues from infected animals showed granulomatous nephritis, meningoencephalitis, hepatitis, and pneumonitis. A large component of the inflammatory infiltrate consisted of plasma cells and lymphocytes. In addition, hyperplasia of B-lymphocyte-dependent regions of lymph nodes and erythrophagocytosis were consistently seen in infected dogs. Infected dogs developed lymphocytosis, hypergammaglobulinemia, anti-encephalitozoon antibodies, and an antigen-specific blastogenic response to E. cuniculi spores. Lymphocyte blastogenic responses to the lectin phytohemagglutinin A (PHA) were depressed compared to controls. Dogs dying during the 2-month experimental trial were bacteremic. The findings of these experiments suggest that postnatal infection results in a demonstrable although seemingly ineffective immune and inflammatory response without detectable clinical disease.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004283:Dog Diseases / Q000097:blood / Q000276:immunology / Q000473:pathology*; D004285:Dogs; D009670:Encephalitozoon cuniculi / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006400:Hematocrit / Q000662:veterinary; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D007958:Leukocyte Count / Q000662:veterinary; D008213:Lymphocyte Activation; D011528:Protozoan Infections / Q000097:blood / Q000276:immunology / Q000473:pathology; D011529:Protozoan Infections, Animal
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M