R. Droual

Preliminary Characterization of a Pleomorphic Gram-Negative Rod Associated with Avian Respiratory Disease

An unidentified, pleomorphic, gram-negative rod (PGNR) bacterium has been isolated from domestic fowl with respiratory disease. The PGNR was isolated in 5% of turkey accessions and 3% of chicken accessions, primarily from the respiratory tract. Preliminary characterization of this organism included reviewing accession records, conducting cultural and biochemical tests, and analyzing cellular fatty acids. The PGNR was also compared with other bacteria capable of inhabiting the avian respiratory system. Biochemical and cellular fatty acid analysis failed to identify the organism, however all 14 isolates were similar.

Ornithobacterium rhinotracheale Infection in Turkey Breeders

A sequence of outbreaks of respiratory disease separated by intervals of about 2 wk occurred on three turkey breeder ranches. The last two ranches affected belonged to different companies and were separated by a distance of 11 km. Mortality on the last ranch was particularly severe among certain segregated groups of turkeys that included toms, heavier birds, and birds undergoing a stressful event such as artificial insemination. On this ranch, percentages of mortality within an 18-day period were 5.2% in toms, 2.4% in hens, 7.4% in heavy toms and 5.4% in heavy hens. Turkeys from 27 to 42 wk of age were examined during the outbreaks. Gross lesions included severe lung consolidation with fibrinous exudate on the pleura and air sacs, petechiae on the epicardium, and increased cloudy fluid in the pericardial sac. Liver and spleen were moderately enlarged. Histologically, there was severe fibrinoheterophilic inflammation in the airways, pleura, and air sacs and severe perivascular interstitial edema in the lungs. Liver had acute coagulative necrosis of hepatocytes associated with occasional thrombosis at the periphery of the liver lobes. Ornithobacterium rhinotracheale was isolated from tissues of the respiratory system, such as infraorbital sinus, trachea, lung, and air sacs, but not from the liver, spleen, or bone marrow. Escherichia coli was isolated less often from lung, air sac, and trachea.

Investigation of problems associated with intramuscular breast injection of oil-adjuvanted killed vaccines in chickens.

Case submissions and a field investigation indicated that oil-adjuvanted killed vaccines may produce long-lived residual lesions in chickens. The lesions typically are yellow opaque cysts along the fascial planes separating the superficial and deep pectoral muscles. Microscopic evaluation shows that most lesions are cysts with thin fibrous capsules, sometimes associated with lymphocytic aggregates and, more rarely, a granulomatous reaction.

Zinc Toxicosis Due to Ingestion of a Penny in a Gray-Headed Chachalaca (Ortalis cinereiceps)

Zinc toxicosis was diagnosed in a gray-headed chachalaca (Ortalis cinereiceps) due to ingestion of a copper-plated zinc penny. Histopathological lesions were most marked in the pancreas. These lesions included apoptosis, zymogen granule depletion, and loss of normal acinar architecture. There was also severe gizzard erosion. Heavy metal analysis revealed abnormal levels of zinc and iron in the liver. Iron pigment in the liver was most concentrated in Kupffer cells. This, along with evidence of erythrophagocytosis in the spleen, suggested that extravascular hemolysis was also associated with zinc toxicosis in this case.

Infectious coryza in meat chickens in the San Joaquin Valley of California.

Two cases of infectious coryza in meat chickens are reported. The first case involved 6-week-old broiler chickens in which only Haemophilus paragallinarum was isolated. The second case involved 11-week-old roaster chickens in which H. paragallinarum and Mycoplasma synoviae were isolated. Both farms were in close proximity to layer-chicken farms where infectious coryza had been previously diagnosed. In both cases, only certain houses on the farm were affected, and mortality in these houses increased slightly. At processing, the condemnation rates for affected houses were considerably higher than rates for unaffected houses. Condemnations for affected houses were mostly due to airsacculitis. A dissecting fibronopurulent cellulitis was a prominent lesion in the second case. This lesion could lead to confusion with chronic fowl cholera and swollen-head syndrome.

Coccidiosis and Necrotic Enteritis in Turkeys

A flock of turkey primary breeder candidates experienced increased mortality within 1 week of being placed in a growout house at 5 weeks 4 days of age. The flock was placed on wood shavings that had been used by an older flock for 2 weeks immediately before placement. Necropsy revealed severe coccidiosis and necrotic enteritis primarily in the distal jejunum, ileum, cecum, and colon. Clostridium perfringens was cultured from intestines. When breeders were selected at 17 weeks of age, total mortality in the affected flock was twice that of a comparable flock placed on fresh litter. Weight at selection in the affected flock was also significantly lower than in flocks placed on fresh litter at the same time in the same growout house.

Femoral Fractures in a Young Male Turkey Breeder Flock

Twenty-two 32-to-35-wk-old male turkeys from a commercial breeding flock were presented to the California Veterinary Diagnostic Laboratory System, Fresno Branch, with a clinical complaint of lameness and increased mortality. Necropsy findings included a unilateral, closed oblique fracture involving the femur in 12 birds. Ten complete femoral fractures had periosteal new bone adjacent to and bridging the fracture. Periosteal callus formation, in this case, suggested that preexisting lesions preceded complete fracture of the femur. Factors such as selection for heavy body weight, lack of exercise, and handling might have contributed to the development and promotion of complete fractures.

Severe Mortality in Broiler Chickens Associated with Mycoplasma synoviae and Pasteurella gallinarum

Severe economic loss due to high mortality and condemnation rates occurred on two commercial broiler facilities. Chickens had moderate-to-severe airsacculitis, pericarditis, perihepatitis, tracheitis, and synovitis. Pasteurella gallinarum was isolated from 16 of 18 pericardia, four of 14 livers, 11 of 16 air sacs, six of seven joints and one of 28 tracheas in pure culture. In addition, Mycoplasma synoviae was isolated from trachea and air sac. Lesions were suggestive of an Escherichia coli septicemia, but E. coli was isolated from only four of 28 tracheas and one of 14 livers in pure culture. A coronavirus was isolated from trachea and lung. Whether this coronavirus represented a vaccine or field strain of infectious bronchitis was not determined. These findings suggested that the severe lesions were due to a concomitant infection with an atypical strain of P. gallinarum.

Proventriculitis and ventriculitis associated with zygomycosis in ostrich chicks

This report describes eight cases of proventriculitis and ventriculitis in ostrich chicks less than 2 months old. Clinical signs included acute onset of lethargy and anorexia in three cases, and chronic weight loss with lethargy and anorexia in four cases; no history was available in one case. There was limited antibiotic therapy in two cases; a third case was treated for giardiasis. Concurrent bacterial, yeast, and viral infections were common. Lymphoid depletion and/or necrosis of bursa, thymus, and spleen suggested severe immune challenge or immunosuppression in many cases. Histologically, there was severe ulcerative proventriculitis and ventriculitis with intralesional fungal hyphae. In two chicks with granulomatous pneumonia, similar fungal hyphae were also observed in the lung. Fungal hyphae were rarely septate, with irregular, non-parallel walls, and ranged in diameter from 7 to 20 microns. Occasional globoid distentions of the hyphae were present. Fungi were identified morphologically as species in the Zygomycetes class; in one case a Mucor sp. was cultured. Zygomycetes appear to be potentially serious opportunistic pathogens of ostrich chicks.

Synovitis, osteomyelitis, and green liver in turkeys associated with Escherichia coli

Birds in seven commercial meat turkey flocks ranging in age from 8 to 11 weeks experienced lameness with swollen joints. In addition to synovitis, the most frequent lesions were swollen liver, green liver, and osteomyelitis. Different serotypes of Escherichia coli were isolated from lesions. Histopathology revealed the absence of respiratory lesions in five flocks and the presence of enteritis in at least five flocks. Hemorrhagic enteritis virus infection was implicated in six flocks by positive serology, diagnostic histopathology, and/or clinical history. Three E. coli serotypes, isolated from different types of lesions in turkeys, were inoculated intravenously into 7-wk-old poults and produced synovitis and swollen livers 3 days postinoculation. These findings suggest that the synovitis, osteomyelitis, and green liver complex is a distinct form of disease associated with E. coli, which may result from hematogenous spread of the bacteria following hemorrhagic enteritis virus infection.