Experimental Co-infection of Low Pathogenic Avian Influenza Virus (H9N2) and Escherichia Coli in SPF Broiler Chickens.

Mohamed Taha; Ahmed Ibrahim; Nabila Osmsn; Ahmed Gaber; Soad Nasef; Mohammed S. Ahmed

Experimental Co-infection of Low Pathogenic Avian Influenza Virus (H9N2) and Escherichia Coli in SPF Broiler Chickens.

2019

The work was implemented to evaluate the pathogenicity of H9N2 when co-infected with theE.coli. Avian influenza H9N2 virus strain A/chicken/Egypt/1618F/2016 which was isolated fromLuxor province during 2016 and E.coli serotype O78 were used in this research. Sixty SPF birdswere divided into 6 groups of ten birds each. At age 21 days, group 1 was inoculated with H9N2only, group 2 received E.coli and three days later received H9N2, group 3 inoculated with H9N2and after three days received E.coli, group 4 was challenged with E.coli and H9N2 at the sametime, group 5 was inoculated with E.coli only, and group 6 was designed as a negative group.Clinical signs, postmortem examination, and serological examination were monitored for 15days. The H9N2 virus presence was assessed in tracheal and cloacal swabs using real-time PCR.The most severe signs and lesions were observed in groups (3, and 4), with also high mortalityrate than other groups with a percentage of 20%. Groups 3, and 4 showed a longer duration invirus shedding in the tracheal and cloacal samples. The hemagglutination inhibition test, group 4showed high HI antibody titer against AIV-H9N2 antigen than other groups, while group 2showed the lowest HI antibody titer against AIV-H9N2 antigen than other groups that receivedonly the H9N2 virus. In conclusion, the outcomes of this study revealed that the infection ofH9N2 with E.coli can exacerbate the clinical outcomes and mortality rates which leads to highereconomic losses in chicken flocks.

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