Abstract
We conducted an epidemiological investigation of an outbreak of H5N1 highly pathogenic influenza (HPAI) virus on an Ohio dairy farm. Findings from the farm shaped a series of bovine challenge studies to confirm our field findings. Cows in the laboratory were assessed for clinical signs and evidence of viral replication. We also evaluated viral transmission to calves via bottle feeding of infected cow’s milk, and transmission to commercial laying chickens co-housed with intranasal (IN) virus-inoculated cattle. IN-inoculated cows did not display clinical signs of infection and virus was not detected in the milk, but mild lesions were observed in the upper respiratory tract on necropsy. Intramammary (IMM) inoculation of cows showed clinical signs consistent with farm findings. IMM-inoculated cows met early endpoint criteria due to severe disease, with milk viral titers reaching 1 x 109 PFU/mL by two days post inoculation. Calves bottle fed infected milk did not display clinical signs associated with HPAI infection, and nasal and oral swabs collected from calves contained only low HPAI viral RNA loads. HPAI viral RNA was not detected in chickens co-housed with IN inoculated cows. Our data indicate that IN inoculation of bovine H5N1 causes mild respiratory disease, while direct virus introduction into the mammary gland caused morbidity and mortality as observed on affected dairy farms. Our data indicate that respiratory transmission is unlikely the primary route of transmission of HPAI H5N1 between cattle, and it is probable that improper cleaning of milking equipment contributes to viral spread.
Co-Author(s)
Carolyn Lee1,2; Bryant Foreman2; Hannah Cochran2; Patricia Boley3; Jennifer Schrock3; Natalie Tarbuck2; Olaitan Shekoni3; Raksha Suresh3; Sara Dolatyabi3; Christina Sanders4; Elizabeth Ohl4; Kaitlynn Starr5; Yehia Saif3; Juliette Hanson3,5; Renukaradhya Gourapura3; Cody Warren4; Scott Kenney3,2; Andrew Bowman2
1 Center for Food Animal Health, Department of Animal Sciences, College of Food, Agriculture and Environmental Sciences, The Ohio State University, Wooster, OH, USA
2 Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
3 Center for Food Animal Health, Department of Animal Sciences, College of Food, Agriculture and Environmental Sciences, The Ohio State University, Wooster, OH, USA;
4 Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
5 The Ohio State University Plant and Animal Agricultural Research biosafety level 3 large animal facility in Wooster, OH, USA
Abstract Category
Avian influenza in mammals, pandemic preparedness, and one health