Avian Metapneumovirus, Hemorrhagic Enteritis Virus and Avian Pathogenic Escherichia coli (APEC) interaction in a finishing turkey farm subjected to colibacillosis-associated mortality

The spectrum of pathogens responsible for colibacillosis-associated mortality is investigated by longitudinal surveys performed in three consecutive production cycles of a finishing toms farm. The surveys mainly focus on the interaction between Avian Metapneumovirus (AMPV), Haemorrhagic Enteritis Virus (HEV) and Avian Pathogenic Escherichia Coli (APEC). Rhino-pharyngeal swabs, cloacal swabs and blood samples were weekly collected for AMPV and HEV PCR detection, and antibody response evaluation, until birds were 14-weeks-old. Mortality was reported and dead birds were examined post mortem. When colibacillosis was suspected, microbiological tests were performed from selected organs. All detected E. coli strains were serotyped and assessed for the presence of virulence-associated genes. In the first cycle, colisepticaemia associated mortality was recorded at week 4, due to AMPV and APEC O78. Late high O78 or O2 APEC associated mortality was observed respectively in the second and third cycle; these outbreaks were correlated to both HEV and AMPV infections.