Abstract

Avian influenza (AI) disease still threat poultry industry in Egypt causing great economic losses. In order to identify and characterize the agent of suggestive clinical cases of AI disease, 28 flocks showing clinical signs suspected to be due to AI infections have been investigated. By slide Haemagglutination (HA), the positive samples were 14/28 and concerning the results of real time- reverse transcriptase polymerase chain reaction (RRT-PCR), 2/14 samples were positive to AI H5, 7/14 to New castle disease virus (NDV), 1/14 to H9 and 4/14 co-infected (2 samples had NDV + AI H5 and others had NDV + AI H9). These positive PCR samples were subjected to further characterization by genotyping and sequencing analysis. The two isolated of H5 AI strain were classified to H5N8 which, related to Russian strains (clade 2.3.4.4) and the genetic analysis approved little relationship between these two H5N8 strain and the commercial AI vaccines with percent (80- 91.7%). So, the researchers should have more monitoring for these viral diseases with effective biosecurity and quarantine measures to minimize the disease occurrence.