A polymerase chain reaction-based test is also available. Although any of these tests can confirm psittacosis, false negatives are possible, so a combination of clinical and laboratory tests is recommended before giving the bird a clean bill of health. It may die within three weeks. Epidemiology Infection is usually by the droppings of another infected bird, though it can also be transmitted by feathers and eggs, and is typically either inhaled or ingested. C. psittaci strains in birds infect mucosal epithelial cells and macrophages of the respiratory tract. Septicaemia eventually develops and the bacteria become localized in epithelial cells and macrophages of most organs, conjunctiva, and gastrointestinal tract. It can also be passed in the eggs. Stress commonly triggers onset of severe symptoms, resulting in rapid deterioration and death. C. psittaci strains are similar in virulence, grow readily in cell culture, have 16S-rRNA genes that differ by <0.8%, and belong to eight known serovars. All should be considered to be readily transmissible to humans. C. psittaci serovar A is endemic among psittacine birds and has caused sporadic zoonotic disease in humans, other mammals, and tortoises. Serovar B is endemic among pigeons, has been isolated from turkeys, and has also been identified as the cause of abortion in a dairy herd. Serovars C and D are occupational hazards for slaughterhouse workers and for people in contact with birds. Serovar E isolates (known as Cal-10, MP, or MN) have been obtained from a variety of avian hosts worldwide, and although they were associated with the 1920s–1930s outbreak in humans, a specific reservoir for serovar E has not been identified. The M56 and WC serovars were isolated during outbreaks in mammals. Treatment Treatment is usually with antibiotics, such as doxycycline or tetracycline, and can be administered through drops in the water or injections. Many strains of C. psittaci are susceptible to bacteriophages. Use as a biological weapon Psittacosis was one of more than a dozen agents that the United States researched as potential biological weapons before the nation suspended its biological weapons program. References The initial content for this article was adapted from sources available at https://www.cdc.gov. External links Psittacosis on Birds n Ways Ornithosis in Pigeons - Pigeonpedia Biological anti-agriculture weapons Atypical pneumonias Bacterial diseases Biological weapons Bird diseases Poultry diseases Respiratory diseases Zoonotic bacterial diseases