Avian Reovirus: Viral Arthritis, Tenosynovitis & Stunting Guide
Clinical guide covering Orthoreovirus genotypic clusters, gastrocnemius tendon rupture, malabsorption syndrome, and breeder immunization.
Scientific Overview
Avian Reovirus (Avian Orthoreovirus / ARV) is a major pathogen of commercial broilers and turkeys. ARV causes viral arthritis, tenosynovitis (lameness and tendon rupture), malabsorption syndrome (Pale Bird Syndrome / Stunting), pericarditis, and severe economic FCR loss.
Etiology & Genotypic Clustering
Avian Reovirus is defined as a non-enveloped double-stranded RNA virus of the family Reoviridae, genus Orthoreovirus. Genomic sequencing classifies field isolates into at least 6 distinct genotypic clusters.
Transmission occurs vertically via eggs or horizontally via fecal-oral routes. High antigenic diversity among genotypic clusters causes frequent autogenous vaccine mismatches (Rafique et al., 2024).
Clinical Forms: Viral Arthritis vs Malabsorption Syndrome
ARV presents in two major clinical syndromes:
- Viral Arthritis / Tenosynovitis: Marked swelling of the hock joint, digital flexor, and gastrocnemius tendon sheaths. Heavy broilers display severe lameness and ruptured tendon cords.
- Malabsorption / Runting-Stunting Syndrome: Severe flock unevenness, poorly digested feed in droppings, pale skin pigmentation (Pale Bird Syndrome), and stunted bone development. Calculate FCR impacts in our FCR Calculator.
Immunization & Autogenous Vaccines
Maternal antibody transfer is vital to protect young chicks. Breeder hens are immunized with live ARV vaccines during rearing followed by inactivated multivalent oil-emulsion boosters containing local genotypic cluster strains before lay (Rafique et al., 2024).