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Chlamydia Psittaci

Chlamydia psittaci bacteria, commonly known as parrot fever or ornithosis, are Gram-negative spherical intracellular parasites. The disease is transmitted to humans from birds. Inhaled aerosol or dust containing Chlamydia psittaci spreads the disease. In birds, the disease is called avian psittacosis (AV). In humans, the disease is known as psittacosis.

Chlamydia psittaci may also infect cats, dogs, sheep, goats, and cattle. In these animals, the disease causes miscarriages, respiratory disease, eye infections, arthritis, and reproductive difficulties. Psittacosis causes flu-like symptoms and may result in severe pneumonia though the disease is rarely fatal. The most likely delivery method of Chlamydia psittaci is by aerosol if the bacterium is used for BW purposes.

Human psittacosis is acquired by physical contact with infected birds or by inhaling dried secretions from infected birds. Person-to-person transmission is rare. The incubation period is 5 to 19 days. Although all birds are susceptible, pet birds (parrots, parakeets, macaws, and cockatiels) and poultry (turkeys and ducks) are most frequently involved in transmission to humans. Other birds that are likely to spread Chlamydia psittaci include pigeons, doves, lovebirds, and mynah birds.

In birds, the disease presents itself as an upper respiratory infection or diarrhea with yellow-green urine or a discharge from the eyes. In humans, the bacterium causes flu-like symptoms: fever, chills, headache, muscle aches, and a dry cough. The bacterium may also cause loss of appetite. Severe infection develops into pneumonia, which shows up on chest x-rays of victims. Endocarditis, hepatitis, and neurological complications may occasionally occur. Severe pneumonia requiring intensive-care support may also occur. Fatal cases have been reported including in the United States. Without antibiotic treatment, between 15-20% cases of psittacosis result in fatalities. With treatment, less than 1% results in fatalities.

Between 1988 and 2003, 935 cases of Chlamydia psittaci poisoning were reported to the Center for Disease Control (CDC). This number is probably lower than the actual number of infections since diagnosis of psittacosis is difficult. The disease can be found worldwide.

Diagnosis of psittacosis can be difficult. Birds that carry the disease are often asymptomatic. Antibiotic treatment may prevent an antibody response, thus limiting diagnosis by serologic methods. Infected birds are often asymptomatic. Tracing of infected birds back to distributors and breeders often is not possible because of limited regulation of the pet bird industry.

The infection can be treated with antibiotics such as tetracyclines or doxycycline or erythromycin in the form of seeds, pellets, orally, or injected. Antibiotic treatment for human Chlamydia psittaci infection lasts 2-3 weeks, and treatment for birds lasts 45 days.