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. 2016 Mar;17(1):27-34.
doi: 10.4142/jvs.2016.17.1.27. Epub 2016 Mar 22.

Assessment of the safety and efficacy of low pathogenic avian influenza (H9N2) virus in inactivated oil emulsion vaccine in laying hens

Jeong-Hwa Shin  1 , Jong Seo Mo  2 , Jong-Nyeo Kim  3 , In-pil Mo  3 , Bong-Do Ha  4
Affiliations

Assessment of the safety and efficacy of low pathogenic avian influenza (H9N2) virus in inactivated oil emulsion vaccine in laying hens

Jeong-Hwa Shin et al. J Vet Sci. 2016 Mar.

Abstract

In Korea, several outbreaks of low pathogenic AI (H9N2) viral infections leading to decreased egg production and increased mortality have been reported on commercial farms since 1996, resulting in severe economic losses. To control the H9N2 LPAI endemic, the Korea Veterinary Authority has permitted the use of the inactivated H9N2 LPAI vaccine since 2007. In this study, we developed a killed vaccine using a low pathogenic H9N2 AI virus (A/chicken/Korea/ADL0401) and conducted safety and efficacy tests in commercial layer farms while focusing on analysis of factors that cause losses to farms, including egg production rate, egg abnormality, and feed efficiency. The egg production rate of the control group declined dramatically 5 days after the challenge. There were no changes in feed consumption of all three groups before the challenge, but rates of the control declined afterward. Clinical signs in the vaccinated groups were similar, and a slight decline in feed consumption was observed after challenge; however, this returned to normal more rapidly than the control group and commercial layers. Overall, the results of this study indicate that the safety and efficacy of the vaccine are adequate to provide protection against the AI field infection (H9N2) epidemic in Korea.

Keywords: H9N2; avian influenza virus; immunity; vaccine.

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Conflict of interest statement

Conflict of Interest: There is no conflict of interest.

Figures

Fig. 1
Fig. 1. Comparison of hemagglutination inhibition (HI) titer of flocks after MS96 (H9N2) challenge. EDC, non-vaccinated flock.
Fig. 2
Fig. 2. Comparison of egg production rate of flocks after MS96 (H9N2) challenge.
Fig. 3
Fig. 3. Comparison of rate of production of abnormal eggs among flocks after MS96 (H9N2) challenge.
Fig. 4
Fig. 4. Comparison of feed consumption rate of flocks after MS96 (H9N2) challenge.
Fig. 5
Fig. 5. Comparison of egg-shell color of flocks after MS96 (H9N2) challenge. Eggshell color fan number ranged from 1 to 15.
Fig. 6
Fig. 6. Comparison of egg yolk color of flocks after MS96 (H9N2) challenge. Egg yolk color fan number ranged from 1 to 15.
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