Avian MetaPneumoVirus (aMPV) infection is an acute, highly contagious infection of the upper respiratory tract in turkeys (Turkey RhinoTracheitis) and chickens (Swollen Head Syndrome). The disease is characterized by coughing, swollen sinuses and nasal discharge. The infection predisposes the birds to secondary infections that may result in a severe outbreak with high mortality. Live and inactivated vaccines are commercially available.