C. psittaci is a bacterium that can cause psittacosis, a potentially serious respiratory disease. There are several synonyms for C. psittaci, including Chlamydophila psittaci, Chlamydia psittaci, and Ornithosis. Despite the different names, they all refer to the same organism that can infect birds, as well as humans who come into contact with infected birds. Proper hygiene and handling of birds can help prevent the spread of this bacterium. In addition, early treatment with antibiotics is important for those who have been exposed to or infected with C. psittaci to prevent serious complications such as pneumonia.