Prevalence and genotypes ofChlamydia psittaciin pet birds of Hong Kong

Abstract Psittacosis, or parrot fever, is a zoonotic disease caused by Chlamydia species associated with birds. One of the causative agents of the disease is Chlamydia psittaci , which is often carried by psittacine and can be highly pathogenic and virulent to humans. In Hong Kong, a city with high population density, psittacosis is a notifiable disease with over 60% of cases in the last decade resulting in hospitalization. However, the source of transmission of C. psittaci and its prevalence in pet birds in Hong Kong are currently unknown. To evaluate the risks of psittacosis transmission through pet birds, we tested the presence of C. psittaci and determined its genotypes in samples obtained from 516 captive birds from households, pet shops, and a veterinary hospital in Hong Kong. Results revealed that five samples (0.97%), collected from budgerigars and cockatiels, were C. psittaci -positive, while 80% of them were obtained from pet shops. The identified strains belonged to genotype A and were closely related to the strain SP15 that was previously discovered in mainland China. Our study highlights the need for genotyping Chlamydia species in psittacosis patients to understand their source(s) of origin.