Psittacosis

• Psittacosis is a chlamydial infection resembling influenza that is spread to humans by the droppings of infected birds.
• Chlamydia psittaci is a type of bacteria that often infects birds.
• Less commonly, these bacteria can infect people and cause a disease called psittacosis.
• Psittacosis can cause mild illness or pneumonia (lung infection).
• To help prevent this illness, follow good precautions when handling and cleaning birds and cages.

pet Red-spectacled Amazon in a parrot cage

History

• A doctor in Europe first described psittacosis as a human disease in 1879.
• A large pandemic of psittacosis in 1929 and 1930 affected about 800 people around the world, including people in the United States.
• Chlamydia psittaci bacteria can infect people and cause psittacosis.
• Up until recently, scientists called the bacteria Chlamydophila psittaci.
• Some people refer to psittacosis as parrot disease or parrot fever, but the bacteria can infect many types of birds.

Causes

• Chlamydia psittaci is a type of bacteria that often infects birds.
• Less commonly, these bacteria can infect people and cause a disease called psittacosis.

• Psittacosis in people is most commonly associated with pet birds, like parrots and cockatiels, and poultry, like turkeys or ducks.

Chlamydia

Transmission

• The bacteria can infect people exposed to infected birds.
• It is important to know that infected birds do not always show signs of disease or seem sick.
• Both sick birds and birds without signs of illness shed the bacteria in their droppings and respiratory secretions.
• When the droppings and secretions dry, small dust particles (including the bacteria) can get into the air.
• The most common way someone gets infected is by breathing in the dust from these dried secretions.
• Less commonly, birds infect people through bites and beak-to-mouth contact.
• In general, people do not spread psittacosis to other people.
• However, this is possible in rare cases.
• There is no evidence that the bacteria spread by preparing or eating chicken meat.
• People at Increased Risk
• People of all ages can get psittacosis, but it is more commonly reported among adults.
• Those who have contact with pet birds and poultry, including people who work in bird-related occupations, are at increased risk:

• Bird owners
• Aviary and pet shop employees
• Poultry workers
• Veterinarians

Signs and Symptoms

In general, psittacosis causes mild illness. The most common symptoms include:

• Fever and chills
• Headache
• Muscle aches
• Dry cough
• Psittacosis can also cause pneumonia, a lung infection, which may require care in a hospital.
• Rarely, psittacosis can result in death.

Onset

• Most people begin developing signs and symptoms within 5 to 14 days after exposure to the bacteria (Chlamydia psittaci).
• Less commonly, people report symptoms starting after 14 days.

Diagnosis

• Diagnosis of psittacosis can be difficult.
• Laboratories use several methods to detect Chlamydia psittaci infection.

Advantages and disadvantages of select C. psittaci diagnostic methods

Advantages and disadvantages of select C. psittaci diagnostic methods

Method	Advantages	Disadvantages
Culture	Yields clinical isolate for genotyping, antimicrobial susceptibility testing, and next generation sequencing	Time-consuming (may take up to a several weeks) Technically difficult; requires specialized expertise Must be cultivated within a tissue culture, mice, or chick embryo Few laboratories perform
Serology (e.g.; complement fixation, microimmunofluorescent antibody test)	Tests are available in many clinical laboratories	Cross-reactivity with other Chlamydia species may occur Requires acute and convalescent samples, and delays confirmation
Molecular (e.g. real-time PCR)1	Rapid detection High sensitivity and specificity Provides results in time for a treatment decision Useful for strain typing	Requires specialized reagents and equipment

• Some tests are only available in specialized laboratories, and many laboratories may not offer any test for C.psittaci.
• Laboratories typically perform tests on sputum specimens or swabs of the nasopharynx and oropharynx or serum, depending on the method used.
• In severe cases, other specimen types may be used.
• Clinicians should confirm the recommended specimen types with the laboratory receiving the specimen.

Blue heron chlamydiosis

Treatment

• Chlamydia psittaci are sensitive to both macrolides and tetracyclines.
• However, tetracyclines are the drugs of choice, unless contraindicated due to reported macrolide failures.
• Tetracyclines are generally avoided in children aged <8 years, and macrolides are the drug of choice for children; however, tetracyclines could be considered when the benefits outweighs the risks, such as in life-threatening conditions or when macrolide failure is suspected.

• As psittacosis can be difficult to diagnose, clinicians should be aware that proper antibiotic treatment ensures quick recovery time.
• People with more severe presentation should be treated with doxycycline right away if psittacosis is suspected.

Complications

• Most people treated properly for psittacosis make a full recovery.
• However, some people have serious complications and need care in a hospital.
• Complications include:

• Serious pneumonia (lung infection)
• Endocarditis (inflammation of the heart valves)
• Hepatitis (inflammation of the liver)
• Inflammation of the nerves or the brain, leading to neurologic problems
• With appropriate antibiotic treatment, psittacosis rarely (less than 1 in 100 cases) results in death.

Prevention

• While there is no vaccine to prevent psittacosis, there are things you can do to protect yourself and others.
• Buy pet birds only from a well-known pet store.
• If you own pet birds or poultry, follow good precautions when handling and cleaning birds and cages (see Safe Bird and Cage Care).

Previous Infections

• Getting psittacosis will not prevent you from future illness.
• If you get psittacosis, you may still get sick from it again in the future.

Safe Bird and Cage Care

• One important aspect of preventing psittacosis is to control infection among birds.

• Keep cages clean; clean cages and food and water bowls daily.
• Position cages so that food, feathers, and droppings cannot spread between them (i.e., do not stack cages, use solid-sided cases or barriers if cages are next to each other).
• Avoid over-crowding.
• Isolate and treat infected birds.
• Use water or disinfectant to wet surfaces before cleaning bird cages or surfaces contaminated with bird droppings.
• Avoid dry sweeping or vacuuming to minimize circulation of feathers and dust.
• Also, remember to thoroughly wash your hands with running water and soap after contact with birds or their droppings.

• Use personal protective equipment (PPE), such as gloves and appropriate masks, when handling infected birds or cleaning their cages.

Psittacosis Resources
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