Aquatic bird bornavirus (ABBV-1), an avian bornavirus, has been reported in wild waterfowl from North America and Europe that presented with neurological signs and inflammation of the central and peripheral nervous systems. The potential of ABBV-1to infect and cause lesions in commercial waterfowl species is unknown. The aim of this study was to determine the ability of ABBV-1 to infect and cause disease in day-old Muscovy ducks (n = 174), selected as a representative domestic waterfowl. Ducklings became infected with ABBV-1 through both intracranial and intramuscular, but not oral, infection routes. Upon intramuscular infection, the virus spread centripetally to the central nervous system (brain and spinal cord), while intracranial infection led to virus spread to the spinal cord, kidneys, proventriculus, and gonads (centrifugal spread). Infected birds developed both encephalitis and myelitis by 4 weeks post infection (wpi), which progressively subsided by 8 and 12 wpi. Despite development of microscopic lesions, clinical signs were not observed. Only five birds had choanal and/or cloacal swabs positive for ABBV-1, suggesting a low potential of Muscovy ducks to shed the virus. This is the first study to document the pathogenesis of ABBV-1 in poultry species, and confirms the ability of ABBV-1 to infect commercial waterfowl.
Spaghetti meat (SM), woody breast (WB), and white striping (WS) are myopathies that affect the pectoral muscle of fast-growing broiler chickens. The prevalence and possible risk factors of these myopathies have been reported in other countries, but not yet in Canada. Thus, the objective of this study was to assess the prevalence and risk factors associated with these myopathies in a representative population of Canadian broilers. From May 2019 to March 2020, 250 random breast fillets from each of 37 flocks (total, 9,250) were obtained from two processing plants and assessed for the presence and severity of myopathies. Demographic data (e.g., sex and average live weight), environmental conditions during the grow-out period (e.g., temperature), and husbandry parameters (e.g., vaccination) were collected for each flock. Associations between these factors and the myopathies were tested using logistic regression analyses. The prevalence of SM, severe WB, and mild or moderate WS was 36.3% (95% CI: 35.3–37.3), 11.8% (95% CI: 11.2–12.5), and 96.0% (95% CI: 95.6–96.4), respectively. Most (85.1%) of the fillets showed multiple myopathies. Regression analyses showed that the odds of SM increased with live weight (OR = 1.30, 95% CI 1.01–1.69) and higher environmental temperature during the grow-out period (OR = 1.75, 95% CI 1.31–2.34). The odds of WB increased with live weight (OR = 1.23, 95% CI 1.03–1.47) and when flocks were not vaccinated against coccidia (OR = 1.86, 95% CI 1.51–2.29). This study documents for the first time a high prevalence of myopathies in Ontario broilers, and suggests that these lesions may have a significant economic impact on the Canadian poultry industry. Our results indicate that environmental conditions and husbandry are associated with the development of breast myopathies, in agreement with the current literature. Future studies are needed to determine how risk factors can promote the occurrence of these conditions, in order to implement possible mitigating strategies.
Aquatic bird bornavirus (ABBV), a type of avian bornavirus, has been associated with inflammation of the central and peripheral nervous systems and neurological disease in wild waterfowl in North America and Europe. The potential of ABBV to infect and cause lesions in commercial waterfowl species is unknown. The aim of this study was to determine the ability of ABBV to infect and cause disease in day-old Muscovy ducks (n = 174), selected as a representative domestic waterfowl. Ducklings became infected with ABBV through both intracranial and intramuscular infection routes: upon intramuscular infection, the virus spread centripetally to the central nervous system (brain and spinal cord), while intracranial infection led to virus spread to the spinal cord, kidneys, proventriculus, and gonads (centrifugal spread). Infected birds developed both encephalitis and myelitis by 4 weeks post infection (wpi), which progressively subsided by 8 and 12 wpi. Despite development of microscopic lesions, clinical signs were not observed. Only five birds had choanal and/or cloacal swabs positive for ABBV, suggesting a moderate potential of Muscovy ducks to shed the virus. This is the first study to document the pathogenesis of ABBV in poultry species, and confirms the ability of ABBV to infect commercial waterfowl.
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