Mycoplasmosis

Mycoplasmosis is a bacterial disease of the respiratory system in birds. The best-known cause is Mycoplasma gallisepticum, which causes chronic respiratory disease in chickens and sinusitis in turkeys. The disease develops slowly, lasts a long time and easily comes back, so it is important to recognise it in time and prevent it spreading through the flock.

Mycoplasmas are tiny bacteria without a cell wall that settle on the mucous membranes of the nose, sinuses, windpipe, air sacs and eyes. They spread:

• through droplets from sneezing and coughing, and through close contact,
• via shared drinkers and feeders,
• via eggs, from hen to chick,
• via people, clothing and equipment moving from one flock to another.

Many birds carry mycoplasmas without signs of disease. The disease flares up when they are weakened by stress: cold and draughts, poor ventilation, ammonia from dirty bedding, overcrowding, moving, laying or a viral infection. Other bacteria then often join in, making the disease more severe.

Respiratory system:

• sneezing, coughing and rattling, especially at night,
• watery or thick nasal discharge, crusted nostrils,
• difficult or rapid breathing, sometimes with the beak open,
• a hoarse, weak voice or complete loss of calls.

Eyes and head:

• frothy discharge in the corner of the eye, watering, closing the eye,
• a swollen area below the eyes due to sinusitis, especially in turkeys.

General signs: drowsiness, a fluffed-up appearance, reduced appetite, stunted growth and a drop in laying. In pigeons, mycoplasmas are a common part of “infectious cold” (ornithosis complex), and in budgies and cockatiels they can cause long-lasting sneezing and nasal discharge.

The disease usually progresses slowly over several weeks, so owners can easily miss it at first. Mild rattling is best heard in the evening when the flock settles down, so it is worth listening to the birds briefly then. If symptoms keep coming back after every change in the weather or bout of stress, that is a common sign of mycoplasmosis.

Mycoplasma gallisepticum has also spread to wild birds. The best-known outbreaks were recorded in North America in house finches and American goldfinches. An affected bird has very swollen, red and crusted eyes, sees poorly, has trouble finding food and often lingers at the feeder.

Inflamed eyes in wild birds can also have other causes, such as injuries, avian pox or other infections. If you see a bird with swollen eyes at a feeder, temporarily stop feeding the birds and clean the feeders thoroughly. Hand the sick bird over to a vet or a wildlife rescue centre, as wild birds are protected and may not be kept at home for long.

• The bird breathes with its beak open, or its tail bobs with every breath.
• Loud rattling or squeaking can be heard.
• Its eyes are closed and crusted, so it cannot see food.
• It is not eating, sits fluffed up and is losing weight.
• Several birds in the flock are sneezing and coughing at once.

The vet makes the diagnosis based on an examination and a PCR test of a swab from the throat, windpipe or eye, and in flocks also blood tests.

Treatment is prescribed by the vet, most often antibiotics such as tylosin or doxycycline, along with drugs to ease breathing if needed. Antibiotics relieve the disease, but mycoplasmas often do not disappear completely. Birds that have recovered can remain carriers and fall ill again under stress. That is why giving antibiotics on your own initiative is not recommended: the symptoms are masked, but the disease stays in the flock.

• Separate the sick bird from the others.
• Put it in a warm, quiet place without draughts, but with enough fresh air.
• You can gently wipe crusted discharge from around the eyes and nostrils with gauze soaked in lukewarm boiled water.
• Put food and a shallow dish of water within reach. Do not pour water into the beak or force-feed.
• Do not use dusty bedding, sprays or scented air fresheners.

• Buy poultry and birds from reliable, healthy flocks.
• Keep new birds separate for at least three to four weeks.
• Ensure good ventilation without draughts and dry, clean bedding.
• Do not mix birds of different ages and origins.
• After visiting someone else's flock, change your clothes and wash your hands.
• Clean feeders and drinkers regularly.
• Prevent contact between domestic poultry and wild birds.

Mycoplasma gallisepticum is not dangerous to people, but good hygiene protects both you and your birds from other diseases.

Mycoplasmosis is a long-lasting respiratory disease that spreads easily and is hard to eradicate completely from a flock. Good husbandry, quarantine for new birds and a timely visit to the vet are the best way to keep it under control.