(Ornithosis, Parrot Fever)
Psittacosis is an infectious disease that is usually transmitted to humans from birds, particularly Psittacine, or parrot-like, birds. It is caused by the bacterium Chlamydia psittaci. Psittacosis is uncommon in New York City. In 2001 there were no cases of psittacosis reported among New York City residents.
Since the disease is spread by birds in the parrot family, it is occasionally found in pet store workers, those exposed to infected birds at pets stores or shows, and people who have recently purchased an infected bird. Pigeon breeders may also be at risk, as well as poultry workers.
Infected birds, even if they do not appear to be sick, can shed bacteria in their feces. People become infected by inhaling aerosolized dried droppings and by handling infected birds. Person to person spread has not been reported. Waste material in birdcages may remain infectious for weeks.
In humans, the symptoms include fever, headache, rash, chills, and sometimes pneumonia. In birds, the symptoms include poor appetite, ruffled appearance, eye or nose discharge, and diarrhea. Birds do not have to be very sick in order to be infectious.
The incubation period may range from 1 to 4 weeks but is usually within 10 days.
Infection does not provide permanent immunity from this disease.
In humans, the diagnosis can be made by demonstrating specific antibodies to C. psittaci. in a blood specimen, or by culture of sputum. In birds, veterinarians can diagnose the infection by testing the feces for Chlamydia or by an antibody test.
Antibiotics such as tetracycline are often prescribed. Tetracycline is effective in both humans and birds. The disease can be severe, especially in older people, who do not receive treatment.
Once infected, birds may remain infected for life, and shed bacteria after treatment if they are stressed from another illness or shipping. If birds are kept as pets, clean the cage often so that feces does not accumulate, dry up, and become airborne. Birds should be purchased from a reliable source that adheres to federal recommendations for psittacosis control. Current laws require that members of the parrot family imported from foreign countries be kept in a bird quarantine station before they can be sold. During the quarantine, they are given food containing tetracycline to reduce the risk of infection, but the duration of treatment is generally shorter than the 45 days necessary to completely treat the bird. Therefore, federal health authorities have recently recommended that breeders and importers ensure that all domestic nestlings and imported birds receive the special tetracycline feed for 45 continuous days in order to prevent the spread of psittacosis from birds to humans.
Last Updated: October 2002