Environmental factors influence the prevalence of infectious bronchitis virus

Abstract

Binary logistic regression analyses were conducted to assess associations between the presence of infectious bronchitis virus (IBV) in broilers and various risk factors: ambient ammonia, oxygen, carbon dioxide, humidity and litter humidity. Pairs of sheds were selected from ten large broiler farms in Canterbury, New Zealand. One shed from each of the pairs had a production or health alteration that suggested the presence of IBV and the other was a control shed. IBV was detected by RT-PCR in 50% of the farms. In 2 of the 5 positive farms where IBV was detected there were accompanying clinical signs that suggested infectious bronchitis (IB). More commonly uncomplicated infections with IBV were asymptomatic under good management. Ambient humidity was the only risk factor that showed an association (inverse) with the prevalence of IBV.