What are Chlamydiosis?

Also known as psittacosis, chlamydiosis is a zoonotic disease that impacts a large number of different species of birds. Caused by the intracellular bacterium Chlamydophila psittaci, the infection is very common in psittacine birds and pigeons, though nearly, if not all avian species are capable of contracting the infection. Some birds may carry the organism however not show symptoms, while others will become slightly to significantly ill, whether immediately upon infection or after becoming stressed. Clinically affected psittacines can have a high rate of mortality.

The disease can be transmitted from birds to humans. The disease in humans is often linked to parrots, giving the disease the nickname “parrot fever”.

A zoonotic disease that affects a large number of bird species, chlamydiosis occurs when a bird is infected by the bacterium chlamydophila psittaci.

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Symptoms of Chlamydiosis in Birds

How severe the symptoms are will depend upon multiple factors:

  • Virulence of the organism
  • Infectious dose
  • Stress 
  • How susceptible the species of bird is to infection

Symptoms of infection in your bird may include the following:

  • Discharge from his nose and eyes
  • Conjunctivitis
  • Sinusitis
  • Greenish/yellowish droppings
  • Fever
  • Inactivity
  • Feathers appearing ruffled
  • Weakness
  • Lack of appetite
  • Weight loss

Types 

Chlamydiosis can occur in birds and can be transmitted to people. A pandemic in human infection by C. psittaci occurred in 1929 in the United States and Europe. Fortunately, there have been improvements in screening for the disease in birds which has decreased the number of people who contract it. Throughout the United States, there are 100-200 cases of the infection in people reported each year. It is thought that the actual number of infections is significantly higher. Fortunately, the infection is easy to treat in people with antibiotics, though it can be fatal should the infected person not be treated.

Causes of Chlamydiosis in Birds

Chlamydiosis is the result of infection by a bacterial organism called Chlamydophila psittaci (also known as Chlamydia psittaci). Transmission is usually through inhaling the bacteria from dried feces. Birds considered carriers will often transmit the bacteria. These birds don’t show symptoms of illness, however the organism is excreted in their droppings.

Diagnosis of Chlamydiosis in Birds

Should you notice your bird appears to be ill, it is best to take him to your veterinarian. After conducting a physical examination, your veterinarian may choose to conduct tests to confirm a diagnosis in your bird. There are several tests that help in diagnosing chlamydiosis; these tests will typically show if your bird has been infected with the bacteria, even if he is not showing signs of illness. The results will differ based on which organs are most impacted and how severe the disease is in your bird.

Increases may be seen in plasma bile acids, AST, LDH and uric acid. The feces of your bird can also be checked for the organism, though this test will not come out as positive if your bird is not actively shedding the bacteria at the time that the sample was collected. Your veterinarian may choose to conduct a radiograph or laparoscopy to see if there is any enlargement of your bird’s liver or spleen or any thickening in his air sacs.

Treatment of Chlamydiosis in Birds

Should your bird be diagnosed with chlamydiosis infection, he will require treatment with antibiotics. Doxycycline is usually the recommended antibiotic and this can be given to your bird by mouth, through an injection or in his water or feed. As the antibiotic will only eliminate bacteria when they are active and dividing and they may be inactive for a period, treatment will be given for a minimum of 45 days to ensure it is effective. 

Doxycycline will often cause your bird to be more susceptible to a yeast infection, so your veterinarian may recommend that he take an anti-yeast medication during treatment. After taking doxycycline for 45 days, your veterinarian will retest your bird to confirm that treatment was effective. As your bird undergoes treatment he will eventually stop shedding the bacteria.

Recovery of Chlamydiosis in Birds

While your bird is being treated it is imperative that steps are taken so that he does not infect people with the bacteria. He should be isolated while being treated and one person should be responsible for all of the cleaning, handling and treatment in order to limit the number of people exposed. It is preferable to handle the healthy birds first before handling the bird with chlamydiosis. 

The individual that is working with the bird and cleaning his environment should wear protective clothing that can be disinfected or thrown away. This will include gloves, eyewear, boots and even a respirator. Your veterinarian will instruct you on how to best treat your bird while minimizing exposure.

About a month after the 45-day treatment with antibiotics is completed, your bird’s droppings should be tested for the bacteria. This will determine if treatment succeeded. Your veterinarian may recommend regular testing to monitor your bird for the bacteria. It is important that during the treatment process you work closely with your veterinarian.

Boarding or exposing your bird to other birds can lead to the bacteria being introduced. Fortunately, the disease can be treated and your bird restored to normal health with proper treatment.