Occurrence: Europe, South Africa, Middle East, Asia.
Species affected: Chickens and turkeys.
Age affected: All.
Causes: Pneumovirus is a single-stranded, 80-200nm RNA virus.
Effects: Sneezing and nasal discharge, foamy conjunctivitis, swelling of infra-orbital sinuses, submandibular oedema, torticollis and cerebral disorientation may occur. Drop in egg production in layers. Mortality 0-10%.
Special note: Swollen Head Syndrome is a common problem in broiler breeders and occasionally in broilers and layers in Europe and South Africa.