Based on genetic analysis, the genus Chlamydia has been reclassified into 2 genera and the organism previously called Chlamydia psittaci has been renamed. These changes have important implications in the diagnosis and management of chlamydiosis (psittacosis).

1. Chlamydia is one genus under the new nomenclature. It has only one species, C. trachomatis, which is primarily a human pathogen.
   
2. Isolates previously grouped under Chlamydia psittaci are now separate species in the genus Chlamydophila. More than 60 species of Chlamydophila have been identified, including C. psittaci, C. felis, C. abortus, and C. pneumonia, the latter organism being primarily a human pathogen.
   
• It is possible that birds can be infected with a variety of chlamydial species, and it is important to know precisely which Chlamydial organism is causing disease in order to understand the sources of infection and management required to prevent further cases.
  
• Serological (antibody) tests can determine the presence of a previous or active infection, but do not differentiate amongst the different chlamydial species. However, PCR-based testing does differentiate these species, and so is an important way to confirm the organism involved in chlamydiosis cases.
  
• Antech offers a variety of serological and PCR-based tests for diagnosing chlamydial infections. Please contact one of our Avian consultants (1.888.VET-INFO) for questions about diagnosing or managing chlamydiosis.