bacterial disease Macaw, Cockatoo Transmissible to humans

Psittacosis (avian chlamydiosis)

Psittacosis, also called avian chlamydiosis, is an infectious disease caused by a bacterium called Chlamydia psittaci. It affects many bird species, but macaws and other parrots are particularly susceptible. This disease is significant bec...

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Definition Signs Causes Transmission Diagnosis Treatment Prevention Complications When to see a vet Prognosis FAQ Sources Affected species

What is it?

Psittacosis, also called avian chlamydiosis, is an infectious disease caused by a bacterium called Chlamydia psittaci.

It affects many bird species, but macaws and other parrots are particularly susceptible. This disease is significant because it can be transmitted to humans as well, making it a public health concern.

In macaws, the infection can remain hidden for a long time before becoming apparent, often triggered by stress such as transport, a change in environment, or another illness.

Key point

This disease requires close monitoring because it can spread to humans and cause respiratory infection that may be severe, particularly in vulnerable people.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Related signs — each one links to its page:

Fatigue Reduction Loss of appetite Weight loss Runny nose Discharge from the eyes Difficulty breathing Diarrhea Jaundice Fever Ruffled feathers Behaviour change Seizures

Signs in macaws are often nonspecific, making diagnosis difficult without veterinary help.

General depression is usually observed, with the bird remaining inactive, fluffed feathers, and reduced eating. Progressive weight loss is common even if appetite seems preserved initially.

Respiratory signs may appear: labored breathing, discharge from the nostrils or eyes.

Digestive problems are possible, with abnormal droppings that may be greenish or more watery.

In more severe cases, yellowing of the mucous membranes (jaundice) or nervous signs such as tremors or seizures may occur.

Some infected macaws show no visible symptoms for long periods while remaining carriers and contagious, particularly during stress.

When to consult without delay

This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.

Causes and risk factors

The disease is caused by the bacterium Chlamydia psittaci, an intracellular microorganism that infects the bird's respiratory tract, digestive system, and sometimes other organs.

Recently purchased, transported, or stressed birds are at greater risk of developing the disease, even if they were silent carriers beforehand.

Crowded aviaries, poor hygiene, a weakened immune system from another illness, or inadequate living conditions increase susceptibility to infection.

Imported birds or those from breeding facilities where the disease is already circulating are particularly at risk.

Transmission

The bacterium spreads mainly through the respiratory route, by inhaling dust contaminated with secretions, feathers, or dried droppings from infected birds.

Direct contact with a sick bird, sharing feeders, or introducing a new carrier bird into an aviary can also spread the disease.

Chicks can also become infected from their parents during feeding.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

The veterinarian relies on the bird's history, clinical examination, and specific laboratory tests, such as those that detect the bacterium or its genetic traces in samples.

Since symptoms are non-specific, these tests are essential to confirm the diagnosis and rule out other possible causes.

Treatment

Treatment relies on a class of antibiotics specifically active against this type of intracellular bacterium, prescribed and monitored by a veterinarian over a prolonged duration.

Supporting care, including nutritional support and hydration, may be necessary depending on the bird's condition.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

Quarantining any new bird before introducing it into an existing aviary helps limit the risk of disease introduction.

Good environmental hygiene, regular cleaning of cages, food and water dishes, and proper ventilation reduce bacterial load.

Avoiding overcrowding and limiting stress sources also help preserve the bird's natural defenses.

Any macaw purchase should ideally include a veterinary check, especially if the bird's origin is uncertain.

Possible complications

Without appropriate treatment, the infection can progress to severe involvement of the respiratory tract, liver, or other organs, potentially endangering the bird's life.

Untreated birds may become chronic carriers and represent an ongoing source of contamination for other birds and humans.

When to see a veterinarian

The macaw appears depressed, remains withdrawn, or refuses to eat for more than one day.

Difficulty breathing or discharge from the nose or eyes develops.

Drop droppings become abnormal in a persistent manner.

Weight loss is apparent despite apparently normal appetite.

Any household member develops flu-like symptoms after contact with the bird; consultation with a human physician is also recommended.

Prognosis

The prognosis is generally favorable if the disease is identified early and treated appropriately with sufficient duration.

Without treatment, or in case of delayed diagnosis, the course can be more serious, particularly in birds already weakened.

Frequently asked questions

Can my macaw be a carrier of psittacosis without being sick?

Yes, some birds harbor the bacteria without showing any signs, especially in the absence of stress. They can nonetheless remain contagious.

Can psittacosis be completely cured in macaws?

With appropriate antibiotic treatment and adequate follow-up over a sufficient period by a veterinarian, recovery is generally possible.

Should I be concerned about my health if my macaw is diagnosed?

Yes, it is recommended to inform your doctor, especially if you show flu-like symptoms, as the disease can be transmitted to humans.

How can I prevent my other birds from becoming infected?

Isolating the sick bird, thoroughly cleaning the environment, and consulting a veterinarian to assess the risk to the rest of the aviary are essential measures.