Mycoplasma gallisepticum: FAQ
Anne Lichtenwalner DVM PhD, University of Maine Cooperative Extension
MG (Mycoplasma gallisepticum) is considered to be the most problematic of the poultry mycoplasmal diseases. This FAQ aims to explain the mycoplasmas in general, this disease in particular, and why it matters to both small and large poultry producers.
What are mycoplasmas? These are very tiny bacteria-like organisms that have less of a cell wall than do other bacteria. There are many species of mycoplasma, and many of them infect only certain animals. For instance, some cause no problems; some are associated with mastitis in cattle, some with respiratory disease in pigs, and some cause mild respiratory infections in wild birds. Some are very host-species specific; for instance, M. bovis infects cattle but not pigs. In contrast, some — like MG — can infect a number of different avian hosts.
What types of birds get MG? MG can cause problems in chickens, turkeys, ducks, geese, game birds, and even wild birds, such as finches.
Is MG a problem in people? No, this disease has not been shown to cause disease in people. However, other respiratory diseases of poultry — like avian influenza — are definitely a problem for people, so contact with birds that show signs of a “cold” or sinusitis (coughing, sneezing, runny eyes, swollen faces) should be limited. If you have sudden deaths in a flock for any reason, seek help from a poultry vet (or the state vet) and MINIMIZE CONTACT. Because of dust, bacteria, fungi, molds, and viruses such as influenza, it’s good to wear a mask while working with the birds. Also, wash hands well after being around the birds and use biosecurity measures (outerwear for barn use only, footbaths, etc).
What does MG infection look like? MG infection can look like many respiratory diseases, and often occurs with several other respiratory diseases, such as Infectious Bronchitis, Newcastle Disease, and/or with E. coli infections. A cough, loud breathing, swelling of the sinuses, and watery eyes are common signs. Decreases in feed intake, egg production or weight gain will occur. Males and also younger birds tend to be more affected, and the disease is worse in the winter months. While it tends to be a more serious disease in turkeys, chickens also will show losses.
How does MG spread? Transmission directly from bird to bird via respiratory secretions, or indirectly from contaminated dust, droplets or feathers, is common. Also, it can be spread vertically: from infected parent birds via the eggs. It can live for days to weeks depending on what kind of material is present: longer in chicken manure or eggs, shorter on clean, dry surfaces. Therefore, removing infected birds and cleaning well, followed by a “down” time for the chicken areas of at least a few weeks, is suggested. In a chicken house, water from unsanitary “drinkers” is the most important source of spreading the infection from bird to bird.
How do I know if MG is present in my flock? Diagnosis can be done via necropsy and culture of ill or dead birds, along with using a blood test to see if your flock has antibodies to MG. Just having antibodies does not mean you have a current problem with MG, but once birds have been infected with it, they may be able to infect other birds, even if they don’t look sick (“carriers”). An infected flock remains infected for life. Contact your veterinarian, or your state department of agriculture, to find out more about MG testing.
How do I disinfect if MG was in my flock? Freezing does not reliably kill MG outside of the host bird, but heat and drying do. Removing the infected flock, thorough cleaning and drying out of the house, and then disinfection with bleach or any of the commercially available products, such as phenolic compounds, should be effective. Leave the premises open (bird-free) for several weeks (hot, dry weather is optimal) before restocking with new birds.
Why should I bother to prevent MG? Because it can be an underlying cause of production losses, can combine with other diseases to kill birds, and can become chronically present in a flock due to “carriers,” it’s worthwhile to prevent MG.
How can I prevent MG in my flock?
Where can I buy MG-free chicks? There is at least one heritage hatchery and there are commercial hatcheries producing NPIP-certified MG-free chickens (this information may change; look at the NPIP website to be sure information is current). ASK YOUR SUPPLIER if the chicks are from an NPIP certified MG free hatchery.
Other helpful sites:
FAQ about MG from Washington State, which gives a nice summary of biosecurity practices for the small poultry producer: http://agr.wa.gov/FoodAnimal/AvianHealth/Docs/Mycoplasmagalliscepticum-website.pdf.
Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.
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