Studies on H9 Avian Influenza in Dakahlia governorate

Abstract

Prevalence of H9 Avian Influenza Virus (AIV-H9) in Dakahlia governorate during 2012 - 2015 was undertaken to update the epidemiology of avian influenza virus infections among poultry flocks in Egypt. A total of 50 chicken flocks were examined (28 broiler flock and 22 layer flock). Results revealed that 18 samples were HA positive while 7 out of 18 samples were positive by chromatographic strip test for common antigen of AIV. Two chicken flocks were found positive AIVH9 by RT-PCR and qrt-PCR. The virus was successfully isolated and propagated in SPF eggs. The result was screened by HA and confirmed by chromatographic strip test, RT-PCR and qrt-PCR. The PCR tests confirmed that the 2 isolates (12B and 19L) were free from contamination with H5 and ND. Both isolates (12B and 19L) were titrated giving EID₅₀ 10 ^8.5 and 10 ⁸. Pathogenicity index (PI) of the isolates (12B and 19L) was assessed experimentally 0.8 and 1.1. Experimentally, the results also revealed faster mortality occurred with both H9 infection and IB live strain vaccination. In conclusion, our results confirmed the continuous circulation of the AIV- H9 in chicken flocks in Dakahlia governorate which exaggerate the respiratory problems in poultry farms.