Mycoplasma synoviae

What species are affected by Mycoplasma synoviae (MS)?

Mycoplasmas tend to be host specific. The usual hosts for Mycoplasma synoviae (MS) are chickens and turkeys, however, it has been also isolated from many other birds species, including pigeons, ducks, geese, and even home sparrows. Rabbits, rats, pigs, and other mammals are not susceptible to experimental inoculation. It does not affect humans.

How is Mycoplasma synoviae transmitted?

Infection between birds occurs readily by direct contact. Infection may occur as early as 1 week of age, but it occurs most commonly when chickens are 4-16 weeks old. Chronic infection follows the acute phase and may persist for the life of the flock. The chronic stage may be seen at any age. If MS is introduced in a flock, usually 100% of the birds become infected, although none or only a few develop joint lesions.

Vertical transmission (from parent to chick) occurs naturally, however, many flocks hatched from infected hens remain free of infection. Vertical transmission plays a major role in spread of MS in chickens and turkeys.

What are the clinical signs of Mycoplasma synoviae?

MS infection most frequently occurs as a subclinical (infection with no clinical signs) upper respiratory infection. It may cause respiratory signs when combined with other pathogens, such as infectious bronchitis virus. MS receives its name because occasionally the bacteria become systemic and result in infection of the membrane that covers the joints (synovium). Clinical signs are observed when joints become affected. The birds become pale comb, lame, and have retarded growth. Swelling of the joints and breast blisters may be observed.

Infection of the respiratory tract may result in inflammation of the air sacs, which results in higher condemnations of meat birds at slaughter.

Egg production is minimally or not affected at all. Eggs produced by an infected flock are suitable for human consumption.

How can Mycoplasma synoviae be diagnosed?

Diagnosis of the bacteria is performed by detection of the pathogen. Detection may be done by PCR (direct detection of DNA) or by isolation and identification from lesions or the upper respiratory tract. PCR procedure is slightly superior to isolation.

Detection of antibodies (immune response) from blood is also possible. Although this assay is less expensive, there are a few disadvantages: it takes 2-4 weeks from infection time to produce detectable antibodies and there is a chance of false positive results, as antibodies stay in the body even after the pathogen is gone. Therefore, confirmation by PCR or isolation is still needed.

Contact WADDL to obtain information about how to collect and submit samples for any of these assays.

If my flock is Mycoplasma synoviae-positive, do I need to depopulate?

There is no requirement to depopulate affected flocks.

What can I do to control Mycoplasma synoviae?

Water hygiene is essential to control not only MS but also any other respiratory disease. Use water nipples. Change the water daily. Treat the water with chlorine or citric acid (mix 2 tbsp in 1 cup of water. Then mix 2 tbsp of this mix in 1 gallon of fresh water).

Although many antibiotics may be effective against MS, it is not recommended to use them unless you obtain an accurate diagnosis. It is possible the birds might have a different condition that is not treatable with antibiotics. Even worse resistance to antibiotic may develop if the antibiotics are not used properly.

Do I need to test my flock for Mycoplasma synoviae?

If you observe sick/dead birds, it is always a good idea to submit samples to the lab to obtain an accurate diagnosis.

Under NPIP Subpart E, exhibition poultry and backyard flocks are required to test only for Pullorum-Typhoid (P-T) and Avian Influenza. However, before moving birds to a different state, consult with the Washington State Department of Agriculture at 800-606-3056 for testing requirements. Some states may require proof of the flock/birds be negative for MS or other conditions.

How can I get more information about Mycoplasma synoviae and testing?

Contact the WADDL-Avian Health Food and Safety Lab at 253-445-4537

Categories: Birds