Persistance of vaccine infectious bronchitis virus in a broiler farm in Colombia

Document Type

Article

Publication Date

3-1-2012

Publication Title

Revista Cientifica de la Facultad de Ciencias Veterinarias de la Universidad del Zulia

Abstract

An assessment of viral charge of the infectious bronchitis virus (IBV) was conducted in a broiler flock, where previously the virus was identified by reverse transcription - polymerase chain reaction (RT-PCR). Presence of IBV was determined in vaccinated poultry with Massachusetts H120 live attenuated immunogen and in non-vaccinated poultry, under field and semi isolation conditions. Samples of tracheal swabs were taken for every four days, since day 1 until 40 days post vaccination. In poultry under the field conditions, IBV was detected by qRT-PCR between 24 - 28 d-old. IBV was detected in vaccinated poultry under the field conditions at 24 - 28 d and in non-vaccinated under the field conditions at 24 d. In the case of vaccinated poultry under the semi-isolation conditions, virus was detected at 28 d. Characterization of the detected strains was made by nucleotide sequencing of the hypervariable region 1 of the IBV S1 gene. Similarity was observed with vaccine derived strain of Massachusetts H120 serotype. It was concluded that there is a presence of the IBV in the farm, in absence of clinical signs or lesions, compatible with the disease. Also found the virus vaccine circulation through nucleotide sequencing. The absence of clinical signs, coupled with the negative results in the qRT-PCR between days 1 - 20, could be a consequence of the change in the vaccination program against Gumboro disease in the farm, where tree live vaccines were replaced with a recombinant vaccine, positively modifying the protection against that entity and decreasing the susceptibility of the birds to the IBV. The results of this study are a basis for further research that asses the IBV vaccine circulation and its role under field conditions.

Volume

22

Issue

2

First Page

120

Last Page

127

ISSN

07982259

Identifier

SCOPUS_ID:84859338732

Documento original

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