Introduction of Chlamydia psittaci into a hospital area by feral pigeons

Pigeons are associated with zoonotic pathogens such as Chlamydia psittaci, the main causative agent of avian chlamydiosis, and related to psittacosis cases in humans worldwide. The aim of the present study was to investigate the occurrence of C. psittaci in feral pigeons (Columba livia) and environmental samples from places frequented by pigeons in a Brazilian hospital area. A cross-sectional study was carried out sampling feral pigeons, their droppings and nest material in a hospital area. Squares in a nearby region with a high density of pigeons were also sampled. Pigeon cloacal swabs (n=123) were collected from each bird, as well as pigeon droppings from the environment (n=77) and material from pigeon's nests (n=28). Chlamydiaceae-PCR targeting the 23S rRNA gene was used as screening. Positive samples were submitted to another PCR targeting the ompA gene of C. psittaci, followed by sequencing and phylogenetic analysis. C. psittaci was detected in 7.5% (17/228) of the samples, 7.3% (12/164) from the hospital area and 7.8% (5/64) from the squares. By sample type, 9.8% (12/123) of the pigeon cloacal swabs, 5.2% of droppings (4/77) and 3.6% of nest material (1/28) were positive for C. psittaci. All sequenced samples corresponded to C. psittaci genotype B. These results demonstrate the occurrence of C. psittaci in urban areas, with emphasis on a hospital area where immunocompromised individuals are present. Adopting a One health approach to prevent the proliferation of the pigeons, health education campaigns and specific recommendations for the hospital administration are essential. Guidance on practices such as not feeding the pigeons, avoiding contact or proximity and removing available areas for roosting and nesting, are measures that will reduce environmental contamination and risk of human exposure to C. psittaci.