Psittacosis

Psittacosis, also known as parrot fever or ornithosis, is a zoonotic infectious disease caused by the bacterium Chlamydia psittaci. Birds are the main reservoir, and human infection usually follows inhalation of aerosolised dried droppings or respiratory secretions from infected birds. Although many human infections are mild, psittacosis can cause pneumonia and occasionally severe complications including endocarditis, hepatitis, and neurologic disease.

Transmission and reservoirs

C. psittaci commonly infects birds, including psittacine birds such as parrots, parakeets, cockatiels, and budgerigars, but human infection has also been linked to pigeons, turkeys, chickens, ducks, and other birds. Many infected birds have no obvious clinical signs but may shed organisms in feces and respiratory secretions for prolonged periods.

Humans are infected mainly by inhaling dust contaminated with dried droppings or respiratory secretions from infected birds. Less common routes include bites and beak-to-mouth contact. There is no evidence that psittacosis is spread by handling or eating poultry products, and documented person-to-person transmission is very rare.

Signs and symptoms

The incubation period is usually 5 to 14 days, although symptom onset may occasionally occur later. In humans, psittacosis ranges from asymptomatic infection or a mild influenza-like illness to severe atypical pneumonia.