Occurrence of Avian Influenza Virus (H9 subtype) in Broiler and Layer Chickens at Sharkia Governorate

Abstract

Avian influenza (AI) is a contagious disease caused by type A influenza viruses. In spite of the mild nature of H9N2 low pathogenic AIV, the virus was isolated from frequent disease outbreaks with high mortality in different parts of the world. In this study, forty-two layer and broiler chicken farms (21/each) suspected to be infected with AIV of different breeds and ages during 2012 -2014 were examined at Sharkia Governorate. The occurrence of AI in chickens using HI assay was 40.47%. Subtyping for H9 and H5 subtypes has been done by specific antisera. The H9 was detected in 30.95% and H5 was 9.52%. However, the occurrence of NDV in chickens was 23.80%. The selected seven AIV isolates representing broiler and layer flocks were confirmed by rRT-PCR using primers and probes specific for Matrix gene, H9 gene, H5 gene and H7 gene. Seven isolates were positive for M. gene indicating AI virus detection, and then 6 out of 7 isolates were positive for H9 gene but negative for H5 and H7 genes. The last isolate was positive for H5 gene, negative for H9 and H7 genes. The phylogenetic analysis for HA gene of the Six H9 AIV isolates showed the placement of the Egyptian viruses within the same lineage of H9N2 viruses that circulated in the region with the parent strain (A/Quail/ Egypt/ 113413v/2011) of G1/97 lineage and other strains that circulating in the Middle East. The circulating H9N2 AIV genetic analysis is pointing to a minor evolution of H9N2 viruses. But at the same time the co-circulation of H5 & H9 subtypes of AIV could be a risk for emergence of new AI viruses. Also, concurrent infection with viral (IBV and NDV) as well as bacterial agents (MG, Salmonella and E. coli) are considered the main cause behind increased mortality in H9N2 positive flocks.

Epidemiological Distribution of respiratory viral pathogens in marketable vaccinated broiler chickens in six governorates in the Nile Delta, Egypt, January to October 2022

“…Under eld conditions coinfection of AI H9 was observed to increase severity of other pathogens (25), including IB (4,30,33,45) or H5 (41,46,47) or ND (48,49), also increase the severity of E.coli (50) as well as secondary bacterial infection (51,52).…”

Epidemiological distribution of respiratory viral pathogens in marketable vaccinated broiler chickens in five governorates in the Nile Delta, Egypt, from January 2022 to October 2022

“…In the present study, 1.4% circulation of the H5 and H9 subtypes of AIV (5/359) could be a risk for the emergence of new AI viruses ( Table-4 and Figures- 3 and- 4 ), which complies with previous results by Gado et al . [ 49 ]. Forty-two layer and broiler chicken farms (21 each) suspected of different breeds and ages being infected with AIV were examined at Sharkia Governorate during 2012–2014.…”

“…H9 and H5 were detected in 30.95% and 9.52%, respectively [ 50 – 52 ]. Under field conditions, AI-H9 coinfection increased the severity of other pathogens [ 25 ], including IB [ 4 , 31 , 35 , 47 ] or H5 [ 49 , 53 , 54 ] or ND [ 55 , 56 ], as well as the severity of Escherichia coli [ 57 ] and secondary bacterial infection [ 58 , 59 ].…”

“…AIV (HP, LP), IBV, and NDV were the main viruses detected alone or in combination in broiler chickens [34]. In recent years, the AI situation in Egypt has become more complicated due to the detection and circulation of many serotypes, including HPAI (H5N1), HPAI (H5N8), and LPAI (H9N2) [48,49]. Yehia et al [39] reported that AIV subtypes and IBV were recorded in 48 out of 53 farms.…”

Epidemiology of Rabbit Hemorrhagic Disease Virus in Different Egyptian Governorates during 2021–2022

“…In Egypt, the initial detection of the disease was in El-Sharkia governorate in the spring of 1991 (Ghanem and Ismail 1992). Then, the virus was detected in Qalubia governorate (Sharawi 1992) and in other Egyptian governorates (Ghanem and Ismail 1992). Since 2007, RHDVa variant strains have been registered in Egypt (Ewees 2007;El-Sissi and Gafer 2008).…”