Propagation of viruses infecting waterfowl on continuous cell lines of Muscovy duck (Cairina moschata) origin

Duck circovirus, duck hepatitis A virus 1, goose parvovirus and goose haemorrhagic polyomavirus are economically damaging pathogens of waterfowl, and replicate poorly or not at all in established cell lines. AGE1.CR, AGE1.CR.pIX and AGE1.CS cell lines, originating from the Muscovy duck, were tested for their suitability to isolate and identify these viruses. Immunofluorescence (IF) and quantitative polymerase chain reaction investigations verified that all cell lines are permissive for all four viruses; however, AGE1.CR.pIX proved to be the most productive and most sensitive for viral infection. IF experiments revealed that the time of one infectious cycle is approximately 12 to 14 h in the AGE1.CR.pIX cells in the case of the three DNA viruses, while it is 10 to 12 h for DHAV-1. Specific viral infectivity and the limit of detection by IF varied between 55 and 1484 copies, depending on the viruses and cell lines. Despite the high sensitivity of the cell lines for viruses, their viral productivity remained relatively low for the investigated field isolates. However, optimization of virus infection and/or the adaptation of the viruses to the cells can raise viral productivity and can make these cell lines suitable for vaccine development and production.