Frank D. Niagro

Beak and feather disease virus and porcine circovirus genomes: intermediates between the geminiviruses and plant circoviruses

SummaryCircoviruses are a diverse group of animal and plant pathogens with undefined relationships to one another but for their non-geminate, non-enveloped capsids and circular, single-stranded DNA genomes. The sequences of the beak and feather disease virus and porcine circovirus genomic DNAs are presented and analyzed in the context of the other members of the family. Sequence comparisons, inferred phylogenies, and geographic occurrence suggest that the ambisense circoviruses, particularly the beak and feather disease virus, represent an evolutionary link between the geminiviruses and the plant circoviruses. We propose that the family members be reclassified into three groups: The family Circoviridae consists of the animal pathogens (beak and feather disease virus and porcine circovirus) that possess ambisense genomes with striking similarities to the geminiviruses. The BBTV-like viruses include the plant pathogens (coconut foliar decay virus, banana bunchy top virus, subterranean clover stunt virus) with a geminivirus-like stem-loop element in their DNAs, and single to multiple component genomes. The chicken anemia virus is an unassigned virus possessing unique characteristics bearing little similarity to the other ssDNA viruses.

Characterization of a new virus from cockatoos with psittacine beak and feather disease

A novel virus isolated from the feather follicles of cockatoos diagnosed as having psittacine beak and feather disease was characterized by electron microscopy, nucleic acid content, and polypeptide composition. Purified virions displayed an icosahedral symmetry, were nonenveloped, and had a mean diameter of 14 to 16 nm negatively stained. Three major viral proteins were identified, with approximate molecular weights of 26.3, 23.7, and 15.9 kDa. The viral nucleic acid was found to be single-stranded DNA based on acridine orange staining, resistance to alkali and ribonuclease, and sensitivity to both DNAse 1 and S1 nuclease. The size of the DNA was estimated to be between 1.7 and 2.0 kb by agarose gel electrophoresis. This size and its circular conformation were confirmed by electron microscopy. A preliminary transmission study using purified virus induced pathological lesions characteristic of those observed in the natural disease. On the basis of the extremely small size of the virions and the single-stranded circular viral DNA, we propose that the etiologic agent of psittacine beak and feather disease represents a previously undescribed viral pathogen.

Comparison of three animal viruses with circular single-stranded DNA genomes.

SummaryNo common antigenic determinants and no DNA sequence homologies were detected when three animal viruses, chicken anaemia agent (CAA), porcine circovirus (PCV), and psittacine beak and feather disease virus (PBFDV), all of which possess circular single-stranded DNA genomes, were compared. Negative contrast electron microscopy showed that PCV and PBFDV particles were 30% smaller than CAA particles and lacked the surface structure of CAA.

A Review of Proventricular Dilatation Syndrome

A Review of Proventricular Dilatation Syndrome Author(s): Christopher R-Gregory, Kenneth S. Latimer, Frank D. Niagro, Branson W. Ritchie, Raymond P. Campagnoil, Terry M. Norton, Rita McManamon, Cheryl B. Greenacre Source: Journal of the Association of Avian Veterinarians, Vol. 8, No. 2 (1994), pp. 69-75 Published by: Association of Avian Veterinarians Stable URL: http://www.jstor.org/stable/27671120 Accessed: 11/01/2010 07:09

ULTRASTRUCTURAL, PROTEIN COMPOSITION, AND ANTIGENIC COMPARISON OF PSITTACINE BEAK AND FEATHER DISEASE VIRUS PURIFIED FROM FOUR GENERA OF PSITTACINE BIRDS

Psittacine beak and feather disease (PBFD) virus, was purified from diseased tissues of a lesser sulphur-crested cockatoo (Cacatua sulphurea), a black palm cockatoo (Probosiger aterrimus), a red-lored Amazon parrot (Amazona autumnalis), and a peach-faced lovebird (Agapornis roseicollis). The histopathology of diseased feathers and follicular epithelium from the different species was compared; basophilic intranuclear inclusion bodies were identified in the follicular epithelium and intracytoplasmic globular inclusions were observed within macrophages located in the feather pulp from the four species. Psittacine beak and feather disease virus antigen was specifically detected by colloidal gold immunoelectron microscopy. The different preparations of purified virions displayed an icosahedral symmetry, were non-enveloped, and had a mean diameter that varied from 12 to 15 nm when negatively stained. Two major viral-associated proteins with approximate molecular weights of 26 and 23 kilodaltons (kd) were consistently demonstrated from the four viral preparations. Purified virions from the four genera were antigenically related. These findings suggest that the PBFD virus purified from numerous genera of diseased birds is similar based on ultrastructural characteristics, protein composition and antigenic reactivity.

Extracutaneous Viral Inclusions in Psittacine Beak and Feather Disease

Thirty-five birds that died with naturally acquired psittacine beak and feather disease (PBFD) were necropsied to identify extracutaneous viral inclusions. Inclusions were found in various tissue sections from 34 of 35 birds. By immunoperoxidase staining, intranuclear and intracytoplasmic inclusion bodies were shown to contain PBFD viral antigen. Inclusion-bearing lesions were widely disseminated but often closely associated with the alimentary tract. Lesions within the palate, esophagus, crop, intestine, bursa of Fabricius, and liver probably serve as sources for viral shedding into the feces.

A Novel DNA Virus Associated with Feather Inclusions in Psittacine Beak and Feather Disease

The nature of feather inclusions was characterized in 32 psittacine birds (30 cockatoos, one peachfaced lovebird (Agapornis roseicollis), and one red-lored Amazon parrot (Amazona autumnalis autumnalis)) with naturally-acquired psittacine beak and feather disease. Intranuclear inclusions within feather epithelial cells and intracytoplasmic inclusions within macrophages in the feather epithelium and pulp cavity contained psittacine beak and feather disease viral antigen when stained by the avidin-biotin complex immunoperoxidase technique. Ultrastructurally, inclusions were observed primarily within macrophages and to a lesser extent within epithelial cell nuclei. Macrophage inclusions appeared as paracrystalline arrays of viral particles. Intranuclear inclusions were less well defined, although scattered viral particles were present. Intracytoplasmic and intranuclear particles in ultrastructural preparations were identified by colloidal gold labeling as psittacine beak and feather disease virus. Feather epithelium was more frequently and severely involved in the disease process than was adjacent follicular epithelium. Plucked feathers with an intact epidermal collar and feather epithelium were preferred to follicular biopsies for histopathologic examination.

Diagnosis of psittacine beak and feather disease (PBFD) viral infection, avian polyomavirus infection, adenovirus infection and herpesvirus infection in psittacine tissues using DNA in situ hybridization

The evaluation of the usefulness of DNA probes in a diagnostic setting to identify nuclear inclusions in selected viral infections (psittacine beak and feather disease viral infection, avian polyomavirus infection, adenovirus infection and Pachecos parrot disease) is reported. A DNA in situ hybridization method was used to detect viral nucleic acid in sections of paraffin-embedded tissues coming from birds naturally and/or experimentally infected. It is concluded that DNA probes used for polyomavirus (FN-19) and adenovirus (FN-23) are able to identify nucleic acid of each virus in the cells with nuclear inclusions, and when used for psittacine beak and feather disease virus (FN-8), and Pachecos parrot disease virus (FN-49) are able to detect viral nucleic acid in cells with or without inclusions.

Diagnosis of Avian Adenovirus Infections Using DNA In Situ Hybridization

Three DNA oligonucleotide probes designated FN-23, FN-48, and FN-96 were evaluated for the diagnosis of aviadenovirus infections by DNA in situ hybridization. Paraffin-embedded tissues were obtained from birds with confirmed adenovirus infection, birds with putative adenovirus infections, and birds with intranuclear inclusions caused by herpesvirus and polyomavirus. In birds with confirmed adenovirus infection, probes FN-23 and FN-96 identified 78% and 72% of diseased individuals, respectively. Only probe FN-48 detected chickens with group II adenovirus infection. In birds with putative adenovirus infection, the DNA probes confirmed aviadenovirus infections in 76% of the population. Probes FN-23, FN-96, and FN-48 detected 85%, 74%, and 18% of adenovirus-infected birds, respectively. None of the DNA probes cross-hybridized with tissues from polyomavirus-infected psittaciform birds or with tissues from a chicken with infectious laryngotracheitis. In contrast, probe FN-23 did cross-hybridize to herpesvirus-infected tissues from two of eight psittaciform birds with Pachecos parrot disease. Probes FN-48 and FN-96 did not react with these tissues.

Viral proventriculitis in chickens

The objectives of the present study were to examine proventriculi of broiler chicks for lesions, and to classify and record the incidence of these lesions. Deep non-purulent necrotizing proventriculitis (accompanied by adenoepithelial hypertrophy and hyperplasia) was the most common (109/220 = 49.5%) light microscopic diagnosis in the proventriculi examined. Degenerating and necrotic alveolar secretory cells had amorphous, granular or vacuolated cytoplasm. Nuclei usually were either pyknotic, karyorrhectic or karyolytic; however, fewer attached or sloughed cells had swollen nuclei with marginated chromatin and clear centres. Basophilic inclusion bodies were never seen. In five cases examined ultrastructurally, hexagonal virus particles were found in intact nuclei (average size = 68.9 nm, n = 89), associated with unbound condensed chromatin, and within vacuolated spaces in the cytoplasm (average size = 62.3 nm, n = 109). DNA in situ hybridization failed to detect adenovirus or polyomavirus nucleic acids. The presence of intralesional virus suggests that a causal relationship might exist between the virus and the proventricular lesions.