Is MS the next ‘big, bad Mycoplasma’ for US poultry?

The US poultry industry is reporting more problems with virulent Mycoplasma synoviae (MS), Naola Ferguson, DVM, associate professor at the University of Georgia, told Poultry Health Today.

MS causes upper-respiratory disease, leg problems, liver problems, pneumonia and eggshell-quality issues. It can spread faster, is more persistent and is more difficult to manage than Mycoplasma gallisepticum (MG), which has been considered the “big, bad Mycoplasma” of poultry, she said.

In adult breeders, MS problems typically start at the peak of egg laying. Broilers are infected vertically, with clinical signs in the flock appearing at about 3 weeks of age, Ferguson said.

Problems with MS are more likely to occur on multiple-age broiler farms. The severity of the disease tends to be worse when it’s cold because of the synergistic effect with respiratory viruses and poor air quality, which can lead to severe airsacculitis and clinical signs, Ferguson said.

The key to keeping ahead of MS is to make use of the sensitive diagnostic tests available — ELISA and PCR (polymerase chain reaction testing). Sometimes companies try to save money by forgoing diagnostics, but without diagnostic information from earlier stages of the flock, it’s difficult to tell when the birds got infected and how to prevent the problem from happening in the future, she said.

For MG control, vaccines and antibiotics are the only options available. Breeders are vaccinated to prevent vertical transmission from hens to broilers. But vaccines aren’t available for MS in the US, so antibiotics are the only option, Ferguson continued.

Antibiotic water treatment controls MS immediately. Producers can give a high dose in a short period of time to try and knock down the levels as soon as MS is diagnosed.

In-feed antibiotics are for long-term MS prevention, for trying to keep the infection level down over time and to help prevent both vertical and horizontal transmission, she explained.