C. U. Meteyer

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.

Meningoencephalitis in commercial meat turkeys associated with Mycoplasma gallisepticum.

Mycoplasma gallisepticum (MG) infection was diagnosed in three different flocks of 12-to-16-week-old commercial meat turkeys displaying torticollis and/or opisthotonos. MG was isolated from the brain, air sacs, trachea, and sinus of one bird with neurological signs. Histological examination of brains in all three cases revealed moderate-to-severe encephalitis with lymphoplasmacytic cuffing of vessels, fibrinoid vasculitis, focal parenchymal necrosis, and meningitis. Birds with neurological signs were seropositive for MG by the serum-plate agglutination and hemagglutination-inhibition tests. The encephalitic form of MG has been described previously but is rarely mentioned in the current literature.

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.

Diagnostic findings in the 1992 epornitic of neurotropic velogenic Newcastle disease in double-crested cormorants from the upper midwestern United States

Neurotropic velogenic Newcastle disease (NVND) occurred in juvenile double-crested cormorants, Phalacrocorax auritus, simultaneously in nesting colonies in Minnesota, North Dakota, South Dakota, and Nebraska and in Lakes Michigan, Superior, Huron, and Ontario during the summer of 1992. Mortality as high as 80%-90% was estimated in some of the nesting colonies. Clinical signs observed in 4- to 6-wk-old cormorants included torticollis, tremors, ataxia, curled toes, and paresis or weakness of legs, wings or both, which was sometimes unilateral. No significant mortality or unusual clinical signs were seen in adult cormorants. Necropsy of 88 cormorants yielded no consistent gross observations. Microscopic lesions in the brain and spinal cord were consistently present in all cormorants from which Newcastle disease virus (NDV) was isolated. Characteristic brain lesions provided rapid identification of new suspect sites of NVND. Lesions were also present in the heart, kidney, proventriculus, spleen, and pancreas but were less consistent or nonspecific. NDV was isolated at the National Wildlife Health Center from 27 of 93 cormorants tested. Virus was most frequently isolated from intestine or brain tissue of cormorants submitted within the first 4 wk of the epornitic. Sera collected from cormorants with neurologic signs were consistently positive for NDV antibody. The NDV isolate from cormorants was characterized as NVND virus at the National Veterinary Services Laboratories, Ames, Iowa. The NVND virus was also identified as the cause of neurologic disease in a North Dakota turkey flock during the summer of 1992. Although no virus was isolated from cormorants tested after the first month of submission, brain and spinal cord lesions characteristic of NVND were observed in cormorants from affected sites for 2 mo, at which time nesting colonies dispersed and no more submissions were received. Risk to susceptible populations of both wild avian species and domestic poultry makes early recognition and confirmation of NVND in wild birds a priority.

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.

Association of Reoviridae particles in an enteric syndrome of poults observed in turkey flocks during 1988

An enteric syndrome of turkey poults, characterized by enteritis, crop mycosis, intestinal changes (pale, thin-walled ballooning with watery contents), and rickets, occurred during 1988 in 74 turkey flocks from different farms belonging to 9 California turkey growers. The flocks ranged in size from 9,000 to 120,000 birds. Pools of intestine sections from 618 birds, representing 78 field cases, were examined. Histopathological examination of the intestines showed a mild to severe atrophy with a reduced depth of crypts, which was more prominent in the distal part of the small intestine. Viral isolation attempts with primary cell cultures of chicken embryo kidney cells were negative. Examination by electron microscopy of negatively stained intestinal specimens revealed the presence of Reoviridae particles of 58.8 to 80 nm in diameter. Enzyme-linked immunosorbent assay results on the intestinal pools for mammalian and group A avian rotaviruses were negative. A statistically significant relationship was found for the presence of Reoviridae particles in the intestines of 10-21-day-old birds. Of the 7 most common pathological conditions analyzed, 2, rickets and intestinal changes (thin-walled ballooning intestine with watery contents), showed a statistically significant association with the presence of Reoviridae particles.

An Atypical Strain of Pasteurella gallinarum: Pathogenic, Phenotypic, and Genotypic Characteristics

The pathogenicity of a strain of Pasteurella gallinarum isolated in Fresno County, Calif., was compared with the American Type Culture Collection (ATCC) strain. Broiler chickens were inoculated intranasally with 10(7) colony-forming units (CFU) and intramuscularly with 10(5) CFU of each strain. The only notable lesions were in chickens inoculated intramuscularly with 10(5) CFU of the Fresno strain, which developed severe myositis at the inoculation site, pericarditis, perihepatitis, airsacculitis, and synovitis. P. gallinarum was reisolated from these lesions. Phenotypic characteristics of the two strains were identical except in reactions in ONPG broth and fermentation of xylose. Protein-banding patterns for the two strains were identical except for a single band difference in the 35-kilodalton region. Restriction endonuclease analysis confirmed that the Fresno strain was a distinct one. Plasmid analysis revealed that the ATCC strain had two plasmids and the Fresno strain had none.

Isolation of Mycoplasma synoviae from the Brains of Commercial Meat Turkeys with Meningeal Vasculitis

Mycoplasma synoviae (MS) was isolated from the brains of 22-week-old commercial meat turkeys displaying severe synovitis and infrequent central nervous system signs. Histological examination of the brains revealed mild-to-severe meningeal vasculitis. The vasculitis ranged from fibrinoid necrosis with little inflammation to a marked infiltration of lymphocytes and plasma cells disrupting the architecture of the vessel wall, accumulating as perivascular cuffs, and involving surrounding meninges. Occasional arteries were undergoing thrombosis. Similar lesions were occasionally seen in renal, synovial, and splenic vessels. MS isolates from the brain, trachea, and joint showed similar protein-banding patterns by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, the protein profile differed markedly from the standard MS reference strain, WVU 1853. This is the first known field case of MS isolation from the brains of turkeys.

Hemorrhagic Enteritis Virus Inclusions in Turkey Renal Tubular Epithelium

Commercial turkeys from four Iowa flocks, two Illinois flocks, and three California flocks were submitted to state diagnostic laboratories because of a variety of health problems. The turkeys ranged in age from 5 to 12 weeks, included both hens and toms, and were owned by five different companies. Some flocks had previously been immunized with live hemorrhagic enteritis vaccine, and other flocks were unvaccinated. In all accessions, basophilic intranuclear inclusion bodies were observed in renal tubular epithelium by light microscopy. Transmission electron microscopy showed that the inclusions consisted of densely packed virus particles. The virions were identified as adenoviruses based upon the icosahedral morphology and average particle diameters of 72 nm. Avidin-biotin immunoperoxidase staining of formalin-fixed, paraffin-embedded kidneys was used to identify this adenovirus as hemorrhagic enteritis virus.