This is an important zoonotic bacterial infection and causes disease in humans and birds. Collectively, these conditions are called as chlamydiosis and caused by Chlamydophila psittaci. When parrots and parakeets are affected, it is psittacosis; for all other birds, it is referred as ornithosis.
Symptoms and lesions: The affected birds appear sleepy, may show fits, shivering, ruffled plumage, nasal discharge, and watery greenish diarrhoea with pasting around the vent region and marked wasting of pectoral muscles. The mortality may be high, large number of birds die during in short period. In pigeons there may be acute respiratory distress alongwith other symptoms described for other birds. The common lesions are atrophy of pectoral muscles, hepatitis and necrosis of liver, enlargement of spleen and fibrino-purulent inflammation of respiratory and peritoneal surfaces alongwith fibrinous pericarditis.
Diagnosis: The disease can be diagnosed from symptoms and PM lesions but confirmation is done by demonstration of organisms in various tissues either by Geimas's stain or by modified acid-fast staining method, The bacteria does not grow on artificial media and hence isolation of the organism from affected tissues by chick embryo/guinea pig/ mouse inoculation is the only alternative.
Prevention and control: Proper hygiene and management can reduce the source of infection. The movement of people in very close vicinity of the pet birds should be restricted to protect human beings from the disease.