Mycoplasmas have been found in most avian species. The most important ones currently in poultry are:
- M. gallisepticum, M. synoviae - chickens and turkeys,
- M. meleagridis, M. iowae - turkeys.
Clinically in chickens the most significant is M. gallisepticum. There are strain variations with regard to severity of disease but virulent ones mainly cause respiratory signs and lesions, especially air sacculitis, and also colonise the reproductive tracts of both male and female birds.
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| Normal air sac |
Mild air sacculitis |
Colibacillosis (Colisepticaemia) |
Transmission can be either by droplets in the air, from bird to bird, or by fomites such as infected shavings, feathers and dust, or by sexual means. Clinical disease develops 4-21 days after infection and therefore it is commonly seen in broilers, which are rapidly growing, at 3-4 weeks of age. It is generally more severe in younger birds. In replacement pullets, it is more commonly seen at stress times, such as placement, point of lay and especially at peak laying in hens, where it has its most damaging effect on overall performance. Hens chronically infected with
M. gallisepticum are likely to have reduced egg production of over 5%.
M. synoviae is usually less severe in broilers than M. gallisepticum, although earlier strains could cause severe respiratory disease. Some strains affect the joints and tendon sheaths of birds and can cause quite severe lameness. This can be painful in hens and cockerels and affect their egg production and fertility respectively.
In turkeys, M. gallisepticum is the most severe infection, causing severe sinusitis, pneumonia and airsacculitis. It can also badly effect breeder production. M. synoviae is more associated with lameness than respiratory signs, but can cause a severe respiratory infection if mixed with
M. meleagridis or with a virus infection. M. meleagridis causes airsacculitis in young birds but clinical respiratory signs may not be apparent. It also damages cartilage and causes leg deformity especially in the tarso/metatarsal bones. M. iowae primarily damages the developing embryo and causes a drop in hatchability.
Tiamutin – targeting mycoplasmas
