Monitoring viral pathogens in poultry dust

Abstract

Knowing the pathogen status of large modern flocks of poultry is a challenge, particularly for viruses. Testing from representative individual chickens is cost-prohibitive and generally involves temperature sensitive samples that require maintenance of cold chain to and within the laboratory. Monitoring of pathogen loads in poultry house dust is an attractive alternative. The dust produced within poultry houses is a mixture of feather dander, and powdered faecal, litter and other material, including pathogens shed from the chickens. It is dry so does not decompose at room temperature and can therefore be transported in the normal mail system. Furthermore it is non-invasive to collect, and is broadly representative of the entire housed flock. Virus may be isolated or sequenced from the dust material. We have shown that monitoring of Marek's disease (MD) virus in broiler house dust samples using real-time quantitative PCR (qPCR) is an effective disease control tool in Australia where it is commercially implemented. As MD virus is shed in dander it is an obvious candidate for this approach. We have now extended our investigations of this method to faecally shed fowl adenoviruses, infectious bursal disease virus, chicken infectious anaemia virus and also infectious laryngotracheitis virus. Results to date indicate that all of these viruses are readily detected and enumerated by qPCR of dust collected from infected chickens and thus this method has potential for routine surveillance of these viruses.