Definition

Psittacosis is an infection caused by Chlamydophila psittaci, a type of bacteria found in the droppings of birds. Birds spread the infection to humans.

Alternative Names

Ornithosis; Parrot pneumonia

Causes

Psittacosis infection develops when you breathe in (inhale) the bacteria. People between 30 to 60 years are commonly affected.

People at high risk for this disease include:

• Bird owners
• Pet shop employees
• People who work in poultry processing plants
• Veterinarians

Typical birds involved are parrots, parakeets, and budgerigars, although other birds have also caused the disease.

Psittacosis is a rare disease. Very few cases are reported each year in the United States.

Symptoms

The incubation period of psittacosis is 5 to 15 days. The incubation period is the time it takes for symptoms to appear after being exposed to the bacteria.

Symptoms may include:

• Blood-tinged sputum
• Dry cough
• Fatigue
• Fever and chills
• Headache
• Joint aches
• Muscle aches (most often in the head and neck)
• Shortness of breath
• Diarrhea
• Swelling in the back of the throat (pharyngitis)
• Swelling of the liver
• Confusion

Exams and Tests

The health care provider will hear abnormal lung sounds such as crackles and decreased breath sounds when listening to the chest with a stethoscope.

Tests that may be done include:

• Antibody titer (rising titer over time is a sign of infection)
• Blood culture
• Sputum culture
• X-ray of the chest
• Complete blood count
• CT scan of the chest

Treatment

The infection is treated with antibiotics. Doxycycline is used first. Other antibiotics that may be given include:

• Macrolides
• Fluoroquinolones
• Other tetracycline antibiotics

Note: Tetracycline and doxycycline by mouth are usually not given to children until after all their permanent teeth have started to grow in, because they can permanently discolor teeth that are still forming. These medicines are also not given to pregnant women. Other antibiotics are used in these situations.

Outlook (Prognosis)

A full recovery is expected if you do not have any other conditions that affect your health.

Possible Complications

Complications of psittacosis may include:

• Brain involvement
• Decreased lung function as a result of the pneumonia
• Heart valve infection
• Inflammation of the liver (hepatitis)

When to Contact a Medical Professional

Antibiotics are needed to treat this infection. If you develop symptoms of psittacosis, call your provider.

Prevention

Avoid exposure to birds that may carry these bacteria, such as parrots. Medical problems that lead to a weak immune system increase your risk for this disease and should be treated appropriately.

References

Geisler WM. Diseases caused by chlamydiae. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 302.

Schlossberg D. Psittacosis (due to Chlamydia psittaci). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. Schlossberg D. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 181.