Circovirus-Like Infection in a Pigeon

Abstract

4,7,10-13 These viruses are similar in that they are small (15-17 nm), icosahedral, and nonenveloped and contain single-stranded circular DNA. Each virus, however, has distinct DNA sequences and antigenicity. Psittacine beak and feather disease virus has the largest host range and has been reported in over 35 species of Old World and New World psittaciforms but has never been reported in other avian families. 4 This is the first case report of circovirus-like infection in a pigeon (Columbiformes). A young female racing pigeon was submitted for necropsy to the Davis branch of the California Veterinary Diagnostic Laboratory System in the fall 1990. The owner had 50 birds (adult and young), and mortality in the squabs was 100%. Three to 5 birds had died per week. Squabs exhibited anorexia and lethargy and died 3-4 days after clinical signs appeared. On gross examination, the pigeon was emaciated, with pectoral muscle atrophy. The mucosal wall of the intestinal tract was slightly red, and luminal contents were foamy and yellow-green. The spleen was enlarged. Air sacs were edematous, and there were caseous cores within the primary bronchi of both lungs. The right lung was consolidated and red. A defined bursa of Fabricius was not evident on gross examination of the site dorsal to the cloaca. The lung and liver were cultured aerobically on blood agar. A Pasteurella sp. was isolated from the lung. Bacteria were not isolated from the liver. Air sacs cultured on selective media for Mycoplasma sp. exhibited no growth. Chlamydia was not identified in Gimenez-stained impression smears of the liver, air sac, and spleen nor in liver, air sac, and spleen impression smears stained with fluorescence-labeled monoclonal antibody specific for Chlamydia a and examined with ultraviolet light. However, Chlamydia psittaci was isolated in a McCoy cell culture system from an organ pool of liver, air sac, and spleen. Viruses were not isolated from pooled tissue homogenates of liver, spleen, lung, brain, and intestine