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Other Names: Mycoplasmosis

Mycoplasmosis is an infection with bacteria of the Mycoplasma genus, resulting in chronic respiratory and joint diseases. The most significant Mycoplasma species in poultry are Mycoplasma gallisepticum (MG), Mycoplasma synoviae (MS), and Mycoplasma meleagridis (MM).
  • Mycoplasma gallisepticum (MG) Infection: MG infection is a significant disease in poultry, causing chronic respiratory disease in chickens, infectious sinusitis in turkeys, and conjunctivitis in finches. MG develops as a slow-spreading infection. All flock members will become infected with MG; however, not all of the birds will show signs of disease. Mycoplasma infections are known to be associated with oxidative damage of the host cells and tissues, resulting from reactive oxygen species generated by both the immune system of the host and the bacterium as its primary virulence factor. MG infection generally causes the most severe clinical signs in young birds, between 4 to 8 week old and/or when birds are concurrently infected with Escherichia coli, M. meleagridis, M. synoviae, Ornithobacterium rhinotracheale (ORT), Infectious Bursal Disease Virus (IBDV), and Newcastle Disease Virus (NDV). When chickens are co-infected with multiple pathogens, it often increases the severity of the clinical signs and makes it more difficult to diagnose.
  • Infectious synovitis: Infectious synovitis is an acute to chronic, systemic disease of chickens caused by infection with Mycoplasma synoviae (MS). Early clinical signs of infectious synovitis typically include lameness, stunted growth, and a pale comb. Some chickens may show non-specific signs of illness such as lethargic behavior or depression. Affected chickens often develop swollen hock joints and/or footpads that are also warm to the touch.
  • Mycoplasma meleagridis (MM) Infection: MM is a pathogen found predominately in turkeys. It is an egg-transmitted disease that primarily causes airsacculitis in young birds that were breed from infected breeders.

Clinical Signs

Nasal discharge
Tracheal rales
Facial swelling
Reduced appetite
Watery eye discharge
Reduced egg production
Warm, swollen hocks or footpads


  • History
  • Clinical signs
  • Physical exam
  • Blood test


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Lincomycin/spectinomycinAdministered orally (50 mg/kg q24h), or in drinking water (528 mg/L for 3-7 days)B Speers
TiamulinAdministered orally (25-50 mg/kg, once a day) or in drinking water (0.25 g/L) for 3-5 daysB Speers, A Garmyn et al., K Marx
TilmicosinAdministered orally (30 mg/kg q24h) or in drinking water (100-500 mg/L) for 5 daysB Speers
Tylosin (Tylan)Administered IM (15-30 mg/kg q6-12h),or in drinking water (250-1000 mg/L)B Speers



  • Cover feed and water to prevent contamination from wild birds
  • Try not to attract rodents: Discard any uneaten feed at the end of the day and pick up any spilled feed. Remove waterers at night and replace with fresh water for birds in the morning. Seal up any possible entry points into the coop (mice can fit anything larger than a quarter inch diameter). Store feed in a sealed plastic or metal container that is not accessible by rodents.

Scientific References

Good Overviews

Age Range

Younger birds are affected more severely than adult birds.

Risk Factors

  • High populations of wild birds on the premises