Effect of multiple cell culture passages on the biological behaviour of chicken anaemia virus.

The Cux-1 isolate of chicken anaemia virus (CAV) was passaged over 320 times in Marek's disease virus transformed chicken lymphoblastoid (MDCC-MSB1) cells. Comparison of the infectivity titres of virus pools derived from viruses that had received 0 (P0), 49 (P49), 170 (P170) and 320 (P320) passages in our laboratory indicated that the yields of infectious virus increased over 100-fold with passage number from P0 to P170. P320 exhibited unusual cell culture growth characteristics in that, unlike its lower passage counterparts, virus-specific immunofluorescence (IF) and cytopathic effect were detected at very low levels at 2 days post infection, with an additional passage of infected cells into fresh medium being required to produce high levels of infectious virus.

Sequence comparison of pigeon circoviruses.

The genome sequences of eight pigeon circoviruses (PiCV) were determined and compared with four previously published sequences. The viruses compared were from the USA, five European countries, China and Australia and included PiCVs from racing, feral, ornamental and meat pigeons and a Senegal dove (Streptopelia senegalensis). The 12 PiCV genomes, ranging from 2032 to 2040 nucleotides in length, displayed similar organizations.

Immunopathologic investigations with an attenuated chicken anemia virus in day-old chickens.

The immunopathologic effects induced by two attenuated chicken anemia virus (CAV) isolates, known as cloned isolate 34 (CI 34) and cloned revertant isolate 18 (CRI 18), that were derived from highly passaged pools of Cux-1 CAV isolate, were compared with those induced by a pathogenic, molecularly cloned, low-passage Cux-1 isolate (CI Cux). This comparison involved the intramuscular inoculation of 1-day-old specific-pathogen-free chicks with each of the viruses and investigation of birds at selected days postinoculation for gross pathology and depletions in the thymic T-cell populations as determined by flow cytometry. Whereas infection with the pathogenic CI Cux produced severe anemia and pronounced bone marrow and thymus lesions, infections with the attenuated CRI 18 and CI 34 isolates produced no anemia, no or mild lesions, respectively, and moderate T-cell depletion.

Diagnosis of goose circovirus infection in Hungarian geese samples using polymerase chain reaction and dot blot hybridization tests.

A polymerase chain reaction (PCR) and dot blot hybridization (DBH) test have been developed for the diagnosis of infection by a novel circovirus of geese (GoCV). These tests were applied to samples of bursae of Fabricius from sick and dead birds from commercial goose farms in Hungary. In this second report of the occurrence of circovirus infection in diseased geese, 103 of 214 (48.

Evaluation of polymerase chain reaction and dot blot hybridisation tests in the diagnosis of pigeon circovirus infections.

Polymerase chain reaction (PCR) and dot blot hybridisation (DBH) tests for detecting pigeon circovirus (PiCV) DNA were developed and evaluated using tissue samples obtained from diseased and clinically normal pigeons, which originated in Belgium and Northern Ireland. When PCR product was visually detected, the limit of detection of the PCR test was 31 fg, while that of the DBH was 1.6p g.

Molecular basis of the attenuation exhibited by molecularly cloned highly passaged chicken anemia virus isolates.

Chimeric virus experiments indicated that the pathogenicity and monoclonal antibody reactivity differences between two molecularly cloned, highly passaged chicken anemia virus isolates could be attributed to the VP1 amino acid change at residue 89. The introduction of this change into a pathogenic cloned low-passage isolate was not sufficient to cause attenuation.

Production and characterisation of monoclonal antibodies to salmon pancreas disease virus.

Six mouse monoclonal antibodies (mAbs) specific to salmon pancreas disease virus (SPDV) were produced following immunisation with purified virus preparations. These mAbs and 2 mAbs resulting from an earlier investigation were characterised. None of the mAbs possessed virus neutralising activity but all reacted with 4 geographically different SPDV isolates as determined by indirect immunofluorescence.

Nucleotide sequence-based identification of a novel circovirus of canaries.

Circovirus-like, spherical particles measuring 16 to 18 nm in diameter were detected in organ homogenates from adult canaries that had died after a short illness characterized by dullness, anorexia, lethargy and feather disorder. A polymerase chain reaction method, based on degenerate primers specific to conserved amino acid sequences in the circovirus replication-associated protein, was used to amplify DNA specific to a novel circovirus, tentatively named canary circovirus (CCV). Sequence analysis of a 510 nucleotide genomic fragment indicated that CCV exhibited 67.

Biochemical characterization of salmon pancreas disease virus.

Salmon pancreas disease virus (SPDV) has been shown to cause severe economic losses in farmed Atlantic salmon (Salmo salar) and has been reported to occur in Europe, Scandinavia and the United States. This paper describes the biochemical characterization of SPDV in terms of its RNA and protein composition. SPDV was purified by precipitation from infected Chinook salmon embryo (CHSE-214) cell-culture supernatant and sucrose density-gradient centrifugation.