What is Avian Chlamydiosis?

board of animal health

Reportable Disease of the Month

Avian Chlamydiosis

Laboratory petri dish testing bacteria

What is it?

A worldwide disease found in wild birds, pet birds and poultry caused by the Chlamydia psittaci bacterium. The disease is particularly common in tropical and subtropical regions. Outbreaks have been declining since the 1970s as the world improves disease detection and response. There are several different strains of the bacteria that can infect people or birds. Infections can be respiratory, digestive or systematic and have been identified worldwide in more than 460 avian species. Some birds carry it and aren’t affected, while others can become sick or die. Among poultry, chickens appear to be slightly more resistant to the disease. Infections have been reported in mammals.

How is it transmitted?

Either inhalation or fecal to oral ingestion through discharged bacteria, which can remain active and infectious for several months in bird litter.  Direct transmission and contaminated environments are the two primary sources of infection. Studies have shown the bacteria can survive for up to 30 days in feces and bedding, and the incubation period is between a few days and several weeks.

What are the clinical signs?

Discharge from the bird’s eyes or beak, green to yellow droppings, fever, inactivity, ruffled feathers, weakness, and weight loss can indicate avian chlamydiosis. Turkeys will most likely become anorexic, develop respiratory distress or display a drop in egg production. The disease is best confirmed by diagnostic testing, and samples should be sent to the University of Minnesota's Veterinary Diagnostic Laboratory in St. Paul.

What is the treatment?

There is no effective vaccine for birds.  Antibiotics can be used in feed to treat infected flocks.

Is there a risk to people?

Yes, people can be exposed to organisms shed from either live or dead infected poultry. Inhalation and direct contact with infected tissues are the primary risks, especially to those working directly with poultry or handling pet birds. Wearing proper protective equipment and hand washing can greatly reduce these risks. Please remember that infected birds and contaminated material should be handled carefully. If contracted, the disease is rarely fatal and can be treated with antibiotics. Flocks or individual birds without clinical signs are still a risk for infection. The Board works closely with the Minnesota Department of Health on this zoonotic disease.

Click here to read about an outbreak in 1986, when 186 suspect cases occurred in Minnesota turkey workers.

How can it be prevented?

Biosecurity helps prevent the introduction or spread of this disease. Thorough cleaning and disinfection of buildings and equipment is very effective as this organism is susceptible to heat and most disinfectants. Producers should isolate new birds or birds returning to the flock from exhibitions or fairs for a period of time. A well-kept building with functioning barriers to separate wild birds also reduces risk.

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