Nationwide Surveillance of Fowl Adenovirus Infection and Coinfection With Other Diseases on Slaughter Broiler in South Korea.

Fowl adenovirus (FAdV) is an infectious pathogen causing economic loss to the poultry industry worldwide. Nationwide surveillance was performed to determine the prevalence and distribution of FAdV with 725 samples collected from145 broiler farms in South Korea. A total of 64 strains were identified using PCR and phylogenetic analysis based on a sequence of hexon gene; 23 of the 64 were FAdV-11/D, 19 were FAdV-5/B, and 12 were FAdV-8b/E. FAdV-1/A and FAdV-8a/E were three strains, respectively; only one strain of FAdV-2/D was detected, and there was no FAdV-4/C. FAdV was detected very frequently at 44.1% of 145 farms, but inclusion body hepatitis (IBH) diagnosed by microscopy was confirmed in 13.8%. Poultry productivity was compared between farms with a single disease or noninfection and farms with multiple infectious diseases such as colibacillosis, antigenic variant infectious bursal disease virus (IBDV) infection, infectious bronchitis, and/or IBH. Coinfection of three or more diseases, including IBH, variant IBDV infection, and infectious bronchitis, had a more deleterious effect on poultry productivity. This study provides that prevalence of various species of FAdV and distribution with other diseases and highlights the need for comprehensive measures against multiple diseases concurrently affecting the broiler in South Korea.