Mycoplasma gallisepticum in Geese: Respiratory Infection Signs and Treatment

Mycoplasma gallisepticum, often shortened to MG, is a contagious bacterial infection that affects the respiratory tract of birds. In poultry, it tends to settle in the conjunctiva, nasal passages, sinuses, and trachea first, but more severe cases can involve the air sacs and lungs. Geese can be affected, even though MG is described most often in chickens and turkeys.

In geese, MG may cause mild upper respiratory signs at first, such as sneezing or watery eyes, then progress to thicker nasal discharge, noisy breathing, or swelling around the face. Some birds stay only mildly affected, while others become much sicker if they are young, stressed, crowded, exposed to poor air quality, or dealing with another infection at the same time.

One important challenge is that birds can become chronic carriers. That means a goose may look better after treatment but still carry the organism and spread it to flockmates later. For pet parents and small-flock keepers, that makes early isolation, testing, and flock-level planning with your vet especially important.

MG is caused by infection with the bacterium Mycoplasma gallisepticum. It spreads both horizontally between birds through respiratory secretions and aerosols, and vertically through infected breeding stock and eggs in some poultry systems. Once it enters a flock, signs may appear quickly or stay hidden for days to months.

Geese are more likely to become sick when the flock is under stress. Common triggers include crowding, poor ventilation, damp bedding, ammonia buildup, sudden weather changes, transport, mixing new birds into the flock, and concurrent infections. These factors do not cause MG by themselves, but they can weaken respiratory defenses and make an existing infection much more obvious.

Backyard and mixed-species flocks can be especially challenging. New birds, birds returning from swaps or shows, and contact with other poultry can all introduce infection. Wild birds may also play a role in disease movement. Because infected birds can remain carriers, one apparently recovered goose may continue to serve as a source of infection for the rest of the flock.

Your vet will usually start with flock history, housing review, and a physical exam. That matters because MG can look similar to other causes of respiratory disease in geese, including avian influenza, Newcastle disease, aspergillosis, chlamydial infection, irritant exposure, and other bacterial infections. The pattern in the flock, recent bird additions, and how fast signs are spreading all help guide next steps.

Testing is often needed for a confident diagnosis. Common options include PCR on choanal, tracheal, or other respiratory samples to look for MG genetic material, culture to try to isolate the organism, and serology such as ELISA for flock-level screening. In some cases, your vet may recommend necropsy on a deceased bird to look for sinus, tracheal, or air sac changes and to rule out other diseases.

Because some respiratory diseases in poultry have public health or regulatory importance, your vet may advise immediate isolation and specific testing before starting treatment. That is especially true if several birds are affected, deaths are occurring, or signs are severe. A diagnosis is not only about naming the infection. It also helps your vet decide whether treatment, long-term management, culling, or flock biosecurity changes make the most sense for your situation.

Prevention starts with biosecurity. Quarantine new birds before introducing them to your flock, avoid sharing equipment with other bird keepers, and clean boots, feeders, waterers, and transport crates regularly. If you visit other poultry flocks, change clothes and footwear before caring for your own birds. These steps help reduce the chance of bringing MG and other respiratory pathogens home.

Housing also matters. Good ventilation, dry bedding, lower ammonia levels, and avoiding overcrowding can reduce respiratory stress and make birds less likely to become clinically ill. Try to limit sudden mixing of age groups or species when possible, and separate any goose that starts sneezing, showing eye discharge, or breathing noisily until your vet advises next steps.

For breeding or larger flocks, sourcing birds from tested, healthy stock is one of the most effective prevention tools. Merck notes that MG-free breeding stock is the method of choice for prevention in poultry systems. Vaccination against MG exists in some poultry settings, but it is not a routine backyard answer for geese and may be regulated or restricted depending on location and flock type. Your vet can help you decide whether testing, quarantine, culling carriers, or flock restructuring is the most practical prevention plan for your birds.