Chlamydia psittaci is a lethal Gram negative intracellular bacterial species that may cause endemic avian chlamydiosis, epizootic outbreaks in mammals, and respiratory psittacosis in humans.
Chlamydophila psittaci affects the parrot family and other avian species. Once infected, these species will be susceptible to symptoms such as appetite and weight loss, diarrhea, sinusitis, and respiratory distress. Humans contract the disease through handling sick birds. Symptoms in humans include fever, cough, dyspnea, mild phryngitis, epistaxis, severe headache, and pneumonia. Certain strains of Chlamydophila psittaci may also infect sheep, goats, and cows.