Submitted to: Office International Epizootics Manual of Standards for Diagnostic Tests
Publication Type: Book / Chapter
Publication Acceptance Date: 7/7/2003
Publication Date: 5/3/2004
Citation: Andersen, A.A. 2004. Avian chlamydiosis (Book chapter for OIE manual of diagnostic tests and vaccines for terrestial animals (mammals, birds and bees), 5th Edition. p. 856-867.
Technical Abstract: Avian chlamydiosis (AC) is caused by the bacterium Chlamydophila psittaci. The genus Chlamydia was recently divided into two genera, Chlamydia and Chlamydophila. All known avian strains are now in the species Chlamydophila psittaci. Chlamydiosis is still the term used for diseases produced by both genera. The avian strains include at least six serotypes that correlate with the avian species from which they are usually isolated. Chlamydiosis, as it occurs naturally in mammalian species and not contracted from avian species, is caused by distinctly different strains of the organism. Depending on the chlamydial serovar and the avian host, chlamydiae cause pericarditis, airsacculitis, pneumonia, lateral nasal adenitis, peritonitis, hepatitis, and splenitis. Generalized infections result in fever, anorexia, lethargy, diarrhoea, and occasionally shock and death. The disease in ducks and turkeys is of particular concern as transmission to humans is common during handling and slaughter of the birds. The diagnosis of AC requires the isolation and identification of the organisms, the demonstration of chlamydiae in tissues, or the demonstration of a four-fold increase in specific humoral antibody, as well as typical clinical signs. A tentative diagnosis can be made in a flock that includes birds with clinical sings of AC as well as a high incidence of birds with high antibody levels.