Part 3 Of 7 Parrot Fever And Enzootic Abortion

Psittacosis or parrot fever and enzootic abortion are both caused by zoonotic Chlamydophila bacteria. Veterinary specialist in public health Dr Jan H du Preez explains how these diseases are contracted by animals and humans, and offers guidelines for managing infection risk.

- Jan H Du Preez

Psittacosis, most commonly known as parrot fever, can be contracted by people who come into close contact with birds, and more particularly those birds of the parrot (Psittacidae) family. The bacteria that causes pstittacosis is Chlamydophila psittaci.

Infections occur naturally worldwide and have been identified in at least 400 avian species, particularly caged birds, colonial nesting birds, raptors, ratites and poultry. Pigeons, turkeys and ducks are most often affected.

Among caged birds affected, more than 70% belong to the parrot family. For practical purposes, all species of birds are a potential source of infection, although the prevalence of infection is significantly greater in caged birds than in wild ones. Some birds carry C. psittaci asymptomatically. Others become mildly to severely ill, either immediately or after they have been stressed by nutritional deficiencies, handling or overcrowding.

C.psittaci lives within the host animal’s cells. In people, parrot fever is readily treated with antibiotics, but can be fatal if left untreated. The disease is also known as bird fever and avian chlamydiosis.

HOW DO PEOPLE CONTRACT THE DISEASE?

Psittacosis is a direct zoonosis contracted as a result of close contact with birds, usually by inhalation of the infectious agent. The droppings of infected birds, who may be asymptomatic or noticeably ill, contain large numbers of organisms. When the droppings dry out, an aerosol is formed in which the organisms are suspended and can be inhaled by people and other animals.

Contaminated feathers also play an important role in spreading the disease. While transmission from one bird to another occurs by inhalation of contaminated droppings and through the ingestion of infectious material, transmission via the eggs (transovarial) of infected birds to their chicks is also possible.