Avian chlamydiosis (AC) is a zoonotic bacterial disease caused by infection with Chlamydia
, a Gram-negative, obligate intracellular bacteria found in wild and domestic birds, mammals, and humans worldwide. Chickens are most commonly infected with C. psittaci
or C. gallinacea
, and less commonly, C. abortus
and C. avium
. C. psittaci
is the most widespread, and found in over 450 different bird species worldwide--including domestic pet birds such as parakeets, cockatiels, and other Psittaciformes. Often times, infected birds remain asymptomatic and may only intermittently shed the bacteria in nasal secretions and in their droppings during stressful events. C. psittaci
and C. abortus
are able to infect humans, with outbreaks of the disease reported in people who had direct contact with infected birds.
Infection can result in a number of different disease manifestations, including conjunctivitis
, enteritis, pneumonia, and hepatitis. Most clinical signs observed in chickens are non-specific, and can include nasal discharge, diarrhea with greenish-yellow feces, ruffled feathers, loss of appetite, and watery eyes.
Chickens become infected with Chlamydia
spp. by inhaling aerosolized respiratory or nasal secretions or contaminated dust, soil, and bedding particles, or through ingestion of contaminated feeders, waterers, or pasture forage.
Avian chlamydiosis is treated with antibiotics, usually tetracyclines (chlortetracycline or doxycycline).