Występowanie nowych wariantów wirusa IB w krajowych stadach kur niosek i kurcząt rzeźnych
Alina Wieliczko , Michał Mazurkiewicz , Julita Wiśniewska
Avian Infectious Bronchitis (IB) still poses serious epizootic and economic problems all over the world despite commonly applied preventive vaccinations. The high serotype variability of the IB virus and its new antigenic variants are likely to be the cause of the disease even in flocks with an immunoprophylaxis programme. The objective of the study was to determine the level of dissemination of new variants/serotypes of IB virus in local flocks of layers and broilers, using serological examinations. The experiment covered 15 flocks of layers (12-63 weeks old) and 26 broiler farms (3-8.5 weeks old), where disorders in the respiratory system, kidney lesion and lowered egg production were reported during rearing periods. The level of IBV antibodies in serum was determined by ELISA using the Massachusetts antigen and by haemogglutination inhibition (HI) with antigens of 5 serotypes of IB virus, namely: M41, D274, D1466, D3128 and D8880. Additionally, some of the sera were examined serogically by HI with the 4/91 antigen. A preliminary serological examination (ELISA and HI) covered the birds at the initial stage of illness whereas the next one (HI) was carried out at intervals of 8-14 days (broilers) or 2-4 weeks (layers). The presence of IBV antibodies was found (using ELISA) in all broiler and layer flocks. However, the percentage of positive results as well as ELISA titer level were more differentiated in broilers. Pairs of sera collected from layers (HI test) showed the highest HI titer level with D1466 serotype in 7 flocks, followed by D8880 antigen in 4 flocks, and 4/91 in 2 flocks. A similar pattern was observed in broilers, where three serotypes of IB virus prevailed among the 6 applied, namely: D1466 (9 flocks), D8880 (7 flocks) and 4/91 (2 flocks).
|Other language title versions||A serological examination of new variants of IB virus in local layer and broiler flocks|
|Journal series||Medycyna Weterynaryjna, ISSN 0025-8628, (B 10 pkt)|
|Publication size in sheets||0.5|
|Keywords in English||Broilers, IBD, Layers, Variants/serotypes|
|Publication indicators||= 0; : 2014 = 0.141; : 2012 = 0.203 (2) - 2015=0.162 (5)|
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