Infectious Synovitis (Mycoplasma synoviae / MS) in Poultry
Guide covering Mycoplasma synoviae etiology, joint exudate, breast blisters, lameness, MS-H vaccine, and Tylosin therapy.
Scientific Overview
Infectious Synovitis is an acute-to-chronic infectious disease of chickens and turkeys caused by Mycoplasma synoviae (MS). It primarily targets synovial membranes of joint capsules, tendon sheaths, and bursa, leading to swollen hock joints, breast blisters, severe lameness, and growth retardation.
Etiology & Transmission of Mycoplasma synoviae
Mycoplasma synoviae (MS) is defined as a cell-wall-less bacterium causing synovitis and subclinical upper respiratory tract infection.
Transmission occurs vertically through breeder eggs and horizontally via respiratory droplets. MS can remain persistent in flocks for the duration of their life cycle.
Pathology: Swollen Hock Joints & Tendon Exudate
Clinical signs and lesions include:
- Lameness & Hock Swelling: Birds wobble on legs with hot, swollen hock joints and footpads.
- Viscid Synovial Exudate: Joint cavities contain cream-colored to honey-like viscous fluid that hardens into caseous pus in chronic stages.
- Sternal Bursitis (Breast Blisters): Prominent fluid-filled blisters over the keel bone due to birds resting on litter.
Control: MS-H Live Eye-Drop Vaccine & Antibiotics
Prevent MS by acquiring MS-free breeder stock and administering live MS-H vaccine via eye drop at 5–6 weeks of age. In active outbreaks, administer water medication with Tylosin, Tiamulin, or Chlortetracycline.
All scientific data, diagnostic criteria, and performance benchmarks presented on this page are derived from published peer-reviewed journals and official veterinary codes:
- Avian Pathology & Diagnostics: World Organisation for Animal Health (WOAH, 2023). Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris, France.
- Poultry Diseases & Histology: Swayne, D.E., et al. (2020). Diseases of Poultry (14th ed.). Wiley-Blackwell / American Association of Avian Pathologists.
- Nutrition & Feed Chemistry: Leeson, S. & Summers, J.D. (2001). Commercial Poultry Nutrition (3rd ed.). University Books, Guelph, Ontario.
- Commercial Breed Standards: Aviagen (2024). Ross 308 & Cobb 500 Broiler Performance Objectives. / Lohmann Breeders (2024). Lohmann Brown Management Guide.