Incidence of Avian Nephritis and Infectious Bronchitis Viruses in Broilers in Egypt

Avian nephritis virus is a new circulating virus in Europe, Australia, and Japan, this virus lead to growth retardation of young chickens by causing interstitial nephritis. Investigation was done in 5 Egyptian governorates (North Sinai, El-Minoufiya, El-Gharbia and El-Behera and Kafr-Elsheikh) on 28 broiler chicken flocks and all the flocks were negative for Avian nephritis virus. In addition, we continued the detection of IBV in the same 28 broiler chicken flocks, resulting that 11 flocks out of 28 flocks, were positive for IBV. Regarding spike glycoprotein (S1) gene, sequencing was done to 5 isolates, which showed that they belonged to Eg/12120s/2012 spike glycoprotein (SP1) gene variant 2. Protectotyping was done using 2 isolates, and 3 types of IB live attenuated vaccines (H120, Ma5, IB primer). In conclusion, this study recorded the extensive circulation of variant 2 IBV in Egyptian broiler chickens. Regarding the pathogenicity of the tested variant and cross protection with available live IB vaccines, it was clear that there no complete cross protection against IBV isolates although of using live attenuated IB vaccines so there a need for further studies to define a more effective program for IB control.