Prevalence of Avian Reo virus, Chicken Infectious Anemia virus, and Fowl Adeno Virus in early age of chicken flocks from 2020 to 2023

Avian Reo virus (ARV), Chicken Infectious Anemia virus (CIA), and Fowl Adenovirus (FAdV) are critical immunosuppressive disease agents that negatively impact the poultry industry's performance worldwide, causing severe economic losses due to direct mortalities or indirect effects on the immune system and other disease outcomes. In this study, the molecular detection of ARV, CIA, and FAdV, was conducted from 2020 to 2023. A total of 1,398 chicken flocks were screened by polymerase chain reaction (PCR), representing different sectors (69 breeders, 14 layers, and 1,315 broilers) at the target age of 1–3 weeks from 24 governorates in Egypt. The ARV prevalence during the study was 2.6%, but it varied from year to year as follows: 6%, 6%, 1.5%, and 2%. In addition, the CIA prevalence was 5.2% over the four years, but it also varied from year to year as follows: 6%, 25.2%, 3.1%, and 1.7%. On the other hand, FAdV had an 8% prevalence and year-to-year incidences of 12.5%, 20%, 5.9%, and 7.7% from 2020 to 2023, respectively. Several cases of multiple co-infection (8 cases) were reported involving various immunosuppressive viruses, as follows: 3 cases (ARV+CIA), 3 cases (ARV+FAdV), 1 case (CIA+FAdV), and 1 case (ARV+CIA+FAdV). The geographic distribution, histological results, and age were all explained. The obtained results indicate the need for continuous monitoring of immunosuppressive viruses and a review of available vaccines and vaccination programs to achieve better prevention and control.