Psittacosis
(Chlamydiophylosis, Parrot Fever)


By James M. Harris, BS, DVM, FRSH
Mayfair Veterinary Clinic, Hobart

Psittacosis is an infection of birds, humans and other mammals caused by Chlamydiaphila psittaci. The organism is found in over 130 species of birds, half of which are Psittacidae (parrot family) . The organism is technically an obligate intracellular species that must be within a cell to reproduce. This is why treatment takes considerable time as it must be out of the bodies cells to be destroyed by medication which must be at adequate blood levels to be effective. Although it does stimulate the hostsí body to produce antibodies against it, the antibodies are not protective against future infections.

The point here is that humans as well as birds can get the infection again. Various cells of the body can be infected. Intestinal infections in birds can result in chronic carriers that shed the organism from time to time. Vaccines are not protective for long periods of time. They are available for turkeys and cats but their efficacy is questionable. In birds signs of infection are very variable making a diagnosis very difficult from symptoms alone. Antibody levels can be an aid in diagnosis but even this is not always accurate as, some birds do not produce adequate antibody levels to measure (African Grey Parrots and Cockatiels). In humans the disease resembles chronic flu with fever, chills, night sweats, coughing, and headaches.

For those of us who are bird fanciers and keep and breed birds, this disease is a risk. If one or one's family member has signs of chronic flu like illness it is important to seek the services of you physician and be sure to advise that you are a bird fancier. Mention psittacosis to the doctor. If this information is not taken seriously as part of the health history seek medical advise elsewhere. Humans do produce an antibody level which rises over a two to three week period if there is an active infection and can be measured from a blood sample. The tetracycline group of antibiotics are used to treat parrot fever and are available in a number of forms. The respiratory route is the source of infections in humans either by direct contact with infected shedding birds, faecal dust, or nasal discharge containing the infective organism. The incubation period in humans is 6 to 15 days. It can take a chronic course lasting for months. Human-to human transmission is very rare.

Although few people die from psittacosis it is a serious problem especially with immune compromised people. If a bird is to be placed in a rest home or other facility with a population of immune compromised residents it would be prudent to pre treat the bird for 45 days before placement. Psittacosis is a common disease with medical and legal considerations. People should be warned of this disease when purchasing birds and established populations should be protected by the quarantine, screening and treatment of new additions before adding to the aviary. The closed aviary practice is well worth the effort.

Copyright remains with author.

RETURN TO ARTICLES