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Braz. J. Microbiol. ; 46(3): 861-865, July-Sept. 2015. tab, ilus
Artigo em Inglês | VETINDEX | ID: vti-17506

Resumo

Newcastle disease vaccines hitherto in vogue are produced from embryonated chicken eggs. Egg-adapted mesogenic vaccines possess several drawbacks such as paralysis and mortality in 2-week-old chicks and reduced egg production in the egg-laying flock. Owing to these possible drawbacks, we attempted to reduce the vaccine virulence for safe vaccination by adapting the virus in a chicken embryo fibroblast cell culture (CEFCC) system. Eighteen passages were carried out by CEFCC, and the pathogenicity was assessed on the basis of the mean death time, intracerebral pathogenicity index, and intravenous pathogenicity index, at equal passage intervals. Although the reduction in virulence demonstrated with increasing passage levels in CEFCC was encouraging, 20% of the 2-week-old birds showed paralytic symptoms with the virus vaccine from the 18th(final) passage. Thus, a tissue-culture-adapted vaccine would demand a few more passages by CEFCC in order to achieve a complete reduction in virulence for use as a safe and effective vaccine, especially among younger chicks. Moreover, it can be safely administered even to unprimed 8-week-old birds.(AU)


Assuntos
Animais , Embrião de Galinha , Galinhas/virologia , Vírus da Doença de Newcastle/patogenicidade , /prevenção & controle , /uso terapêutico , Vacinas Virais/uso terapêutico , Técnicas de Cultura de Células , Células Cultivadas , Galinhas/imunologia , Vírus da Doença de Newcastle/classificação , Vírus da Doença de Newcastle/crescimento & desenvolvimento , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Cultura Primária de Células , Vacinação , Vacinas Atenuadas/efeitos adversos , Vacinas Atenuadas/imunologia , Vacinas Virais/efeitos adversos , Vacinas Virais/imunologia
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