Delayed vaccine virus replication in chickens vaccinated subcutaneously with an immune complex infectious bursal disease vaccine: quantification of vaccine virus by real-time polymerase chain reaction.

The distribution of the immune complex vaccine virus for infectious bursal disease (IBD) in tissue was examined and the viral loads of the organs were quantitatively compared. One-day-old specific pathogen free (SPF) and maternally immune broiler chickens were injected subcutaneously with the vaccine. Lymphoid and non-lymphoid tissues were collected at various time intervals during the experiment to test for infectious bursal disease virus (IBDV)-RNA by using reverse transcriptase-polymerase chain reaction (RT-PCR).

Studies on the pathogenesis of chicken infectious anaemia virus infection in six-week-old SPF chickens.

The pathogenesis of chicken infectious anaemia virus (CAV) infection was studied in 6-week-old and one-day-old SPF chickens inoculated intramuscularly with graded doses of Cux-1 strain (10(6)-10(2) TCID50/chicken). Viraemia, virus shedding, development of virus neutralizing (VN) antibodies and CAV distribution in the thymus were studied by virus isolation, polymerase chain reaction (PCR), immunocytochemistry (IP) and in situ hybridization until postinfection day (PID) 28. In 6-week-old chickens infected with high doses of CAV, viraemia and VN antibodies could be detected 4 PID and onward without virus shedding or contact transmission to sentinel birds.

Interaction of chicken anaemia virus and Cryptosporidium baileyi in experimentally infected chickens.

The natural occurrence of concomitant chicken anaemia virus (CAV) and Cryptosporidium baileyi infection was described earlier. In this experiment, 1-day-old chickens were infected with CAV alone (anaemia virus infected, AI) or followed by inoculation with 8 x 10(5) C. baileyi oocysts orally at 1 wk of age (anaemia virus and Cryptosporidium infected, ACI).

Serological survey on the prevalence of chicken anaemia virus infection in Hungarian chicken flocks.

A serological survey on the prevalence of chicken anaemia virus (CAV) infection was performed by using the indirect immunofluorescence (IF) and the virus neutralization (VN) tests in commercial Hungarian chicken populations. By the indirect IF test, a total of 846 serum samples from 13 meat-type parent flocks of two breeds were investigated between 10 and 62 weeks of age. All flocks were found to be positive for anti-CAV antibodies, and the rates of antibody-positive birds among flocks ranged from 40 to 93.

Concurrent cryptosporidiosis and chicken anaemia virus infection in broiler chickens.

Concurrent infection with Cryptosporidium baileyi and chicken anaemia virus (CAV) was observed in a flock of 8000 4-week-old broiler chickens. The birds, showing overt symptoms of stunted growth and 25% mortality from hatching to 4 weeks of age, harboured the protozoan in the epithelial cells of the bursa of Fabricius and the urodeal portion of the cloaca. This is the first report on an outbreak of avian cryptosporidiosis associated with CAV.

Isolation of chicken anaemia virus from broiler chickens.

Chicken anaemia virus (CAV) infection was demonstrated, by both serology and virus isolation, in 1- to 6-week-old broiler chickens originated from various parent flocks in Hungary. Total losses in the broiler flocks were estimated at 7 to 8% and about 25% of the chickens failed to reach target body mass by the 7th week of life. The clinical signs, postmortem lesions and histopathological changes of the affected chickens were similar to those of naturally occurring CAV-induced infectious anaemia of young chickens.

Isolation of a reticuloendotheliosis-like virus from naturally occurring lymphoreticular tumours of domestic goose.

Naturally occurring lymphoreticular tumours were found in an adult goose flock. Diffuse and/or nodular lymphoma-like tumours occurred in the spleen, liver, pancreas, intestines and rarely in other internal organs. Osteopetrosis-like lesions and signs of other diseases such as amidostomosis, enteritis, arthritis and air sacculitis were also observed.

Demonstration of immunoglobulin m on avian lymphoid leukosis lymphoma cells by the unlabelled antibody peroxidase-antiperoxidase method.

A series of 12 avian lymphoid leukosis and nine Marek's disease lymphomas from experimental and natural infections were studied for the demonstration of immunoglobulin M and Marek's disease tumour-associated surface antigen by the unlabelled antibody peroxidase-antiperoxidase method using impression smears and formaldehyde-fixed paraffin-embedded tissue sections. Results indicate that immunoglobulin M, the characteristic antigenic marker of avian lymphoid leukosis virus-induced B cell lymphomas, can be detected not only on tumour imprints but also in deparaffinised tissue sections. Of 12 chickens with proven lymphoid leukosis lymphomas, 10 were clearly diagnosed by demonstration of a predominance of immunoglobulin M-bearing cells in the lesions.

Lymphoreticular tumour in pen-raised pheasants associated with a reticuloendotheliosis like virus infection.

An outbreak of a lymphoproliferative disease in pheasants is described. Nodular or diffuse tumours were found on the head and in various internal organs. The lesions consisted of undifferentiated lymphoreticular cells.

Genetic control of resistance to subgroup A and subgroup C tumour viruses in Rhode Island Red fowl: evidence for linkage between the tumour virus a (tva) and tumour virus c (tvc) loci.

A study, using the Rhode Island Red (RIR) strain of fowl maintained at Houghton Poultry Research Station, was made to investigate the genetic control of cellular response to infection with viruses of subgroups A and C. Family matings within the RIR strain and test-crosses between the RIR parents and White Leghorn (WL) parents of known ararcrcr genotype were set up to ascertain linkage between the tumour virus a (tva) and tumour virus c (tvc) loci. The results confirmed that in this RIR strain, the two loci, tva and tvc, control the cellular response to viruses of subgroups A and C, respectively, as reported in other breeds of fowl (WL and New Hampshire).