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D L Graham

Publications and source records attributed to D L Graham.

65 records · Page 4Linked to original sources
PubMed1973

Falcon Herpesvirus, the etiologic agent of inclusion body disease of falcons.

A viral agent has been isolated from five fatal cases of naturally occurring inclusion body disease in three different falcon species, namely, the prairie falcon (Falco mexicanus), the red-headed falcon (F. chiquera), and the peregrine falcon (F. peregrinus). The virus has been shown to possess the physical, chemical, and biological properties of a herpesvirus and has been used to reproduce inclusion body disease in the prairie falcon, merlin (F. columbarius), and American kestrel (F. sparverius). A similar disease was also produced with this virus in the great horned owl (Bubo virginianus), screech owl (Otus asio), and ring-necked turtle dove (Streptopelia risoria). Serological comparison of the falcon herpesvirus with other known avian herpesviruses revealed that the virus is antigenically closely related to a pigeon herpesvirus and an owl herpesvirus while differing from the former in host range. No antigenic relationship to infectious laryngotracheitis virus, duck virus enteritis, or Marek's disease virus could be demonstrated.

Animals↗
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Genetic diversity in twenty variants of the avian polyomavirus.

To determine if different pathotypes of the avian polyomavirus (APV) exist and to compare the genomes of APVs originating from different geographic areas, dates, and species of birds, the partial sequences of 18 APVs were determined. New viral sequences were compared with three published APV sequences. Two of the new viruses had identical sequences. Forty point mutations were found at 31 loci. A 27-bp deletion was found in the VP2 and VP3 open reading frames of one virus. A duplication of the putative origin of replication and adjacent enhancer region was previously reported in one APV. Smaller duplications involving the origin in one APV and a second enhancer region in another were discovered. All duplications were in tissue culture-adapted viruses, suggesting they occurred during the isolation process. Excluding duplications and the deletion, maximum variation between viruses was small (11 bp). A maximum parsimony tree was constructed that contained three major branches. The three earliest isolates were on separate branches. The European viruses were confined to branch I, but APVs from the United States were on all three branches. Lovebird, budgerigar, and macaw APVs were also on each of the three branches, suggesting that species-specific pathotypes have not developed. Most nonsynonymous mutations occurred in a small portion of the VP2 and VP3 open reading frames, demonstrating a selection for these mutations. That a glycine at VP2 221 will inhibit virus replication in chicken embryo fibroblasts (CEFs) has been previously reported. In contrast, six of seven of the new APVs isolated in CEFs had a glycine at VP2 221.

Amino Acid Substitution↗
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Characterization of a gram-positive bacterium from the proventriculus of budgerigars (Melopsittacus undulatus).

The cellular, cultural, and biochemical characteristics of eight isolates of a large gram-positive bacillus that are commonly observed as apparently normal flora in the proventriculus of budgerigars (Melopsittacus undulatus) were determined. The bacterium was highly pleomorphic and changed markedly in both diameter and length when subcultured on agar media. The bacterium was facultative anaerobic and capnophilic, hemolytic on blood agar, and formed flat colonies with irregular edges after incubation for several days. All isolates grew on sodium azide agar but did not grow on MacConkey agar. The isolates were catalase-negative and oxidase-negative and did not reduce nitrate. All isolates failed to utilize arginine, lysine, ornithine or tryptophane but produced acid from glucose, galactose, levulose, maltose, melibiose, starch, and sucrose. All isolates produced acetoin from glucose and hydrolyzed esculin. The eight isolates could not be identified to either genus or species level based on the descriptions of currently classified organisms in the division Firmicutes as described in Bergey's Manual of Systematic Bacteriology.

Animals↗
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Characterization of a reo-like virus and its isolation from and pathogenicity for parrots.

Necropsy of an African Grey parrot (Psittacus erithacus) revealed subcutaneous hemorrhages, multiple foci and microfoci of necrosis in the liver, spleen, bone marrow, and intestinal lamina propria, mild air sacculitis, and epicarditis. A virus, isolated from the liver, was non-enveloped, was polyhedral with a diameter of 84.9 +/- 3.4 nm, possessed a double-stranded RNA genome, and was stable at pH 3.0 for 30 minutes and at 56 C for up to 120 minutes. The virus was propagated in cell culture, purified by limiting dilution, and inoculated into two African Grey parrots. The experimental infections were fatal on the 8th and 9th days postinoculation in the orally and intramuscularly inoculated birds, respectively, and produced hemorrhages and necrotic lesions that recapitulated those of the index case.

Animals↗
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Papovavirus infection in hand-fed parrots: virus isolation and pathology.

Papovavirus infection was diagnosed in 44 parrots of at least 18 species exclusive of the budgerigar (Melopsittacus undulatus). The birds were 14 days to 4 months old and had been removed from parental care and hand-fed as nestlings. The birds had been unexpectedly found dead after having evidenced no premonitory signs of illness, or they died following a short (12-to-48-hour) period of lassitude and anorexia. In most cases, necropsies revealed pallor, multiple hemorrhages, splenomegaly, and hepatomegaly with multifocal necrosis. Histological lesions included multifocal to diffuse hepatic necrosis that spared the periportal hepatocytes, karyomegaly of splenic reticuloendothelial cells and cells in other tissues, membranous glomerulopathy, and necrosis of bursal medullary lymphocytes. Papovaviruses were isolated from two cases, and papovavirus infection was confirmed in 27 of the birds by the fluorescent-antibody test using a conjugate against a papovavirus isolated from a budgerigar.

Animals↗
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Pathogenesis of reticuloendotheliosis virus infection in ducks.

A new isolate of reticuloendotheliosis virus (REV) from ducks, RU-1, was used to experimentally infect white pekin ducks. Embryonal or neonatal infection usually resulted in persistent viremias, no REV antibody development, and inability to mount antibody responses against bovine serum albumin (BSA) or sheep red blood cells (SRBC). In contrast, infection at 21 days of age resulted in transient viremias, which terminated coincident with REV antibody development. These ducks remained persistently infected, however, based on virus isolations from peripheral blood lymphocytes. Ducks infected at that age were immunologically competent against BSA and SRBC unless they had been embryonally bursectomized, in which case they behaved virologically and immunologically like those infected at an early age. Bursectomy by itself did not prevent responses against the antigens. Total mortality during 4- or 6-month experimental periods ranged from 80 to 100% in REV-infected groups, regardless of age at infection, route of exposure, or whether the ducks were intact or bursectomized. Most deaths were from non-neoplastic conditions (stunting, bacterial infections), but 17 of 69 (25%) infected ducks developed a variety of neoplasms, including lymphosarcomas, histiocytic sarcomas, and spindle-cell sarcomas.

Animals↗
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Characterization of the avian polyomavirus-associated glomerulopathy of nestling parrots.

The glomerulopathy occurring in nestling nonbudgerigar parrots with avian polyomavirus (APV) disease was examined in 10 parrots. Glomerular lesions were characterized by the presence of dense, periodic acid-Schiff (PAS)-positive material that expanded the mesangium and that narrowed and at times occluded capillary lumina. PAS-staining was found to be more sensitive than hematoxylin and eosin in the detection of the lesions. Ultrastructurally, finely granular electron-dense material was found in massive intracapillary and mesangial condensates. Capillary endothelial cells exhibited changes consistent with cellular swelling. No evidence of chronic glomerular changes was observed. Immunofluorescent staining demonstrated that the PAS-positive, electron-dense condensates were complexes of IgG, avian polyomavirus antigen, and, in one bird, IgM. Viral DNA was detected in the serum of all six birds examined. Anti-APV antibodies were also present in all five serum samples examined. These findings suggested that the pathogenesis of this acute immune complex glomerulopathy and other APV-associated lesions depends on the presence of an appropriate ratio of circulating virus and anti-APV antibody.

Animals↗
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Failure of maternally derived yolk IgG to reach detectable concentrations in the sera of nestling budgerigars (Melopsittacus undulatus).

Transfer of maternal immunoglobulin G (IgG) to the yolk and nestling was investigated in the budgerigar. Specific antibodies to avian polyomavirus and Newcastle disease virus could be detected in 82% of yolk extracts of eggs from seropositive hens. Using a double immunodiffusion assay with anti-chicken IgG antibodies, IgG could also be detected in yolk supernatants with virus neutralizing activity. In all assays, IgG concentrations in the yolk extracts were significantly less than those of the adult budgerigar serum. No antiviral activity was detected in nestling serum. Examination of nestling serum with the double immunodiffusion assay and an immuno-dot-blot technique specific for IgG showed that detectable concentrations of IgG are not present in nestling serum until after the yolk sac is fully absorbed. This observation, coupled with the absence of specific anti-viral antibody in nestlings of seropositive hens, indicated that none of the yolk sac antibody reached the nestling circulation.

Animals↗
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Production of avian polyomavirus seronegative budgerigars (Melopsittacus undulatus) from seropositive adults.

Adult budgerigars (Melopsittacus undulatus) with 2 years of breeding experience were removed from an aviary with enzootic avian polyomavirus (APV) disease and maintained in an isolation unit. Following a 7-month respite from breeding, these birds were allowed to breed without interruption for 2 years. Although the adults were seropositive both at the beginning and end of the experiment, all 102 of their offspring were seronegative. These data suggest that APV can be eliminated from a budgerigar aviary with the use of simple management techniques.

Animal Husbandry↗