Psittacosis and its Zoonotic Potential

Psittacosis is caused by Chlamydophila psittaci (Chlamydia psittaci), it is a zoonotic bacterial pathogen with wide range of hosts, that includes birds, humans and other mammals. Psittacosis is derived from the Greek word ‘psittakos’ means parrot (first used in 19th century). Chlamydia psittaci primarily affects birds – tamed (pet birds like parrots, finches), feral (pigeons), domesticated (poultry) and wild bird species. Chlamydial bacteria have been found in more than 70 species of wild birds, with the greatest chlamydial diversity identified in Europe (Stokes HS et al., 2021). In psittacine birds (parakeets, small and large parrots sp.), the infection can vary widely from asymptomatic carriers to severe systemic illness mainly affecting respiratory and gastrointestinal systems. In non-psittacine birds this infection is referred as ornithosis, affects poultry like turkey, geese and ducks, feral birds like pigeons and others. The incidence in ducks and turkeys are more common compared to chicken. There are several reports of the transmission of Chlamydia psittaci from ducks and turkeys to humans and even an outbreak of chlamydiosis was investigated in workers at a duck farm and processing plant during winter 1989 (Hinton DG et al., 1993). In humans upon get in contact with the infectious secretions, susceptible individuals develop flu-like symptoms and in some cases, atypical pneumonia.