Psittacosis (chlamydia)

Psittacosis is a bacterial disease caused by Chlamydia psittaci. It is most often mentioned in connection with parrots, budgerigars, cockatiels and other pet birds, so in everyday speech it is often simply called “chlamydia”. The same disease in pigeons, wild birds and poultry is called ornithosis, which we cover in a separate article. Psittacosis is a zoonosis, which means it can be passed on to humans, so it is important to recognise it in time.

The bacterium is shed in droppings, discharge from the nose and eyes, and saliva. When droppings dry, they turn into dust that spreads through the air together with dander and small feathers. A bird most often becomes infected by inhaling this dust or through shared food and water.

What makes this disease special is that many parrots carry the bacterium without any signs of illness. Such a bird looks healthy but sheds the bacterium from time to time, especially when it is under stress. Stress is caused by:

• moving, being sold or arriving in a new home,
• overcrowded cages and aviaries, fairs and shows,
• breeding and feeding young,
• poor diet, cold or another illness.

That is why the disease often appears a few weeks after a new bird has arrived in the home. Young birds and smaller species usually become more seriously ill.

The signs are often non-specific and can develop slowly. If you notice several of them together, suspect psittacosis.

General signs:

• the bird is fluffed up, sleepy and uninterested in its surroundings,
• it eats less or refuses food, and loses weight,
• the plumage is untidy and ruffled,
• it vocalises less or falls completely silent.

Eyes and respiratory system:

• red, swollen or watery eyes, often only one eye,
• discharge from the nostrils, soiled feathers around the nose,
• sneezing, wheezing, rapid breathing or open-beak breathing.

Digestion and droppings:

• loose droppings, often yellow-green or lime green in colour, which points to liver involvement,
• increased drinking and watery droppings.

In advanced disease there may be unsteadiness when walking, falling off the perch, trembling or weakness of the legs and wings.

Do not wait for the bird to “get better on its own”. Contact an avian vet immediately if:

• the bird is sitting fluffed up on the cage floor,
• it is breathing heavily, with its beak open, or its tail bobs with every breath,
• it has not eaten or drunk for more than a day,
• the droppings are bright green, yellow or watery,
• it falls off the perch, is trembling or cannot stand,
• several birds fall ill within a short time or one dies.

The vet takes swabs from the eye, throat and cloaca and sends them for PCR testing, often along with blood. A single negative result does not always rule out the disease, because the bird sheds the bacterium only intermittently, so the test is sometimes repeated.

Psittacosis is treated with antibiotics from the tetracycline group, most often doxycycline, which are prescribed by the vet. Treatment is long, usually several weeks, and must be completed even if the bird recovers sooner. Stopping treatment early leaves birds as carriers. If there are several birds in the home, the vet usually treats them all.

• Separate the sick bird from the others in a separate room.
• Keep it in a warm, quiet and dimly lit place, away from draughts.
• Put food and a shallow dish of water on the cage floor so that it does not have to hop up onto the perches.
• Never pour water into the beak and do not force-feed the bird.
• Cover the cage floor with paper and change it every day, dampening it lightly before removing it.
• Do not give antibiotics on your own initiative. The wrong drug or too short a course masks the disease and makes diagnosis harder.

• Keep a new bird separate for at least 30 to 45 days and have it examined by a vet.
• Buy birds from reputable breeders, preferably with a negative test.
• Clean the cage regularly using damp methods, without raising dust.
• Provide good ventilation, a varied diet and as little stress as possible.
• Avoid contact between your birds and other people's birds of unknown health.

Yes. People most often become infected by inhaling dust from dried droppings and feathers, less often through a peck or close contact with the beak. In humans the disease most often resembles flu: high temperature, headache, muscle pain, a dry cough, and it can progress to pneumonia. Older people, pregnant women and people with weakened immunity are particularly at risk.

• Wear gloves when cleaning the cage, and a protective mask as well if the bird is sick.
• Do not clean up droppings and litter dry and do not blow the dust away. Dampen them first.
• Wash your hands thoroughly with soap after every contact with the bird.
• Do not kiss the bird on the beak or share food with it.
• If you get flu-like symptoms, see a doctor and be sure to tell them you keep birds.

Psittacosis is a common and insidious disease of parrots, because a bird can carry it without visible signs. A quick diagnosis, treatment prescribed by a vet and consistent hygiene protect both the bird and your family.