A106 - Chlamydophila psittaci
(formerly Chlamydia psittaci)

Chlamydophila psittaci infections in exotic birds represent a very common clinical problem. Signs range from acute devastating disease to poor feathering. Various estimates have been made as to the incidence of chlamydial carriers. In exotic birds, infection rates are said to vary from 10-90% overall, with infection rates approaching 100% in some closely held collections. When looking at the percentage of the exotic bird population found to be infected, only a small percentage show overt clinical evidence of illness based on physical exam, radiography, and hematologic assessment. Some of the carriers may remain in that state for years with little or no clinical problems and it is these birds that are contagious to cagemates and people. Carriers without clinical signs may also be suffering from chronic low-grade hepatopathies. Chlamydophila psittaci is one of the most prevalent infections in aviculture and species of this genus can infect other animals and humans. Outbreaks of psitticosis can quickly spread through an entire aviary with devastating results. A retrospective study (Fudge, Proc. AAV 1992) showed that the shedding rate (antigen positive) is highest in young birds. After that time, many birds quit shedding and remain infected. Long-term effects of chlamydial infections can be multi-systemic, including afflictions such as liver disease.

Serological methods are currently available. Unfortunately, a significant number of ill and healthy carrier birds do not make a measurable antibody which is especially true with cockatiels, budgerigars, and young parrots. Cell culture methods are technically difficult and expensive, with a long turnaround time. The PCR assay is now available to specifically detect Chlamydophila psittaci DNA in avian blood and feces samples. The sensitivity was found to be between 60-600 fg of chlamydial DNA, which is approximately 6 to 60 organisms per sample. Positive result confirms Chlamydia psittaci infection.