Chlamydia psittaci is a bacterium that can be transmitted from pet birds to humans. In humans, the resulting infection is referred to as psittacosis (also known as parrot disease, parrot fever, and ornithosis). Psittacosis often causes influenza-like symptoms and can lead to severe pneumonia and nonrespiratory health problems. With proper treatment, the disease is rarely fatal. From 1987 through 1996, CDC received reports of 831 cases of psittacosis (1), which is an underestimate of the actual number of cases because psittacosis is difficult to diagnose.

During the 1980s, approximately 70% of the psittacosis cases with a known source of infection resulted from human exposure to caged pet birds; of these persons, the largest group affected (43%) included bird fanciers and owners of pet birds. Pet shop employees accounted for an additional 10% of cases. Other persons at risk include pigeon fanciers and persons whose occupation places them at risk for exposure (e.g., employees in poultry slaughtering and processing plants, veterinarians, veterinary technicians, laboratory workers, workers in avian quarantine stations, farmers, and zoo workers). Because human infection can result from brief, passing exposure to infected birds or their contaminated droppings, persons with no identified leisure-time or occupational risk can become infected.

In this report, C. psittaci infection in birds is referred to as avian chlamydiosis (AC). The bacterium C. psittaci has been isolated from approximately 100 bird species and is most commonly identified in psittacine birds such as parrots, macaws, cockatiels, and parakeets. Among caged, nonpsittacine birds, infection with C. psittaci occurs most frequently in pigeons, doves, and mynah birds. The incidence of infection in canaries and finches is believed to be lower than in other psittacine birds.

The recommendations in this compendium provide effective, standardized procedures for controlling AC in the pet bird population, an essential step in efforts to control psittacosis among humans. This compendium is intended to guide public health officials, physicians, veterinarians, persons in the pet bird industry, and others concerned with the control of C. psittaci infection and the protection of public health.