Avian pneumovirus infections of turkeys and chickens

Avian pneumoviruses (APVs) cause major disease and welfare problems in many al eas of the world. In turkeys the respiratory disease and the effect on egg laying performance are clearly defined. However; in chickens, the role of APV as a primary pathogen is less clear, although it is widely believed to be one of the factors involved in Swollen I-lead Syndrome. The mechanisms of virus transmission over large distances are not understood, but wild birds have been implicated. APV has recently been reported in the USA for the first time and the virus isolated was a different type or possibly a different serotype from the APVs found elsewhere. Good biosecurity is crucial for controlling infection and highly effective vaccines are available for prophylaxis. Although different subtypes and possibly different serotypes exist, there is good cross protection between them. Diagnosis is usually based on serology using ELISAs, but the available kits give variable results, interpretation is difficult and improved diagnostic tests are required. (C) Harcourt Publishers Ltd.