Dynamics of influenza virus transmission in a swine herd and analysis of risk factors for recurrent infections

摘要

Influenza in swine is considered to be a relatively simple infection with short duration of infectiousness. At the population level, the disease is commonly recognized by the sudden appearance of respiratory signs and also by rapid recovery of the sick animals. Results from recent field studies, however, suggest that circulation of influenza A virus (IAV) in individual animals may not be as simple as previously thought. The epidemiology of influenza in large multi-site and multi-source herds, in particular, is not well described. Therefore, the objectives of this study were to describe patterns of IAV infection in pigs after weaning in multi-source nursery herds, and to determine factors that contribute to such patterns.