All secretions and excrement are infectious. The pathogen is mostly ingested via droplets -- i.e. the inhaling of infectious faeces, dust or aerosols. The upper respiratory tract is the most probable route for this kind of transmission. The bacteria can also be transmitted via contact or smear infections, which almost exclusively affect individuals with very close contact to the infected animals.
Transmission route: dried, contaminated bird faeces => infectious dust => respiratory system => bronchioles => pneumonia.
The incubation period is 3-29 days, but may even last up to 100 days. Symptoms in birds include pneumonia, coughing, weight loss, ruffled feathers, diarrhoea, eye and nose discharge. The disease ends fatally within a few days or weeks, or takes a chronic form during which the animals seem to recover, but still shed the pathogen.
In humans, it causes mainly fever and general symptoms, followed by pneumonia.
The drugs of choice are Tetracyclines (Oxytetracycline) that have to be administered over a longer period of time.
Birds must be put in quarantine and tested for chlamydophila to prevent psittacosis. The general rules of hygiene for the handling of birds must be adhered to.