Duration of cross-protection between subtypes A and B avian pneumovirus in turkeys

The degree and duration of clinical and virological cross-protection between avian pneumovirus subtypes A and B were examined in two-week-old pneumovirus antibody-free turkeys. The turkeys were inoculated with either a virulent subtype A (Belgian isolate A/T6/96), a virulent subtype B (Belgian isolate B/T9/96), an attenuated subtype A or an attenuated subtype B, and challenged homologously and heterologously with virulent avian pneumovirus two,...