Infection of tissue such as the lung, eye, genitals and urinary tract can be caused by the intracellular bacterium Chlamydiae that can cause diseases in birds (particularly parrots) and koalas as well as humans.
Chlamydiae are a group of organisms that are not bacteria, but closely resemble bacteria. They act as parasites inside human cells, cause the destruction of the cell where they multiply, and then move on to infect more cells. The infection is transmitted sexually or by close contact with other patients or infected animals.
It may cause pneumonia (psittacosis), eye infections (trachoma), and infections of the urethra (urine tube from bladder to outside – non-specific urethritis), vagina (pelvic inflammatory disease) and genitals (lymphogranuloma venereum).
Chlamydial infections are difficult to diagnose, but swabs from the affected area are sometimes positive. Blood tests can also be used to make the diagnosis with internal infections. It can be cured by antibiotics such as tetracyclines, erythromycin and azithromycin.