Abstract:

Objective To analyze the investigation and management of a Chlamydia psittaci infection case for evidence in following prevention and control of similar infection. Methods A field epidemiological investigation was conducted for a confirmed psittacosis case that occurred in Chengdu City in April 2023. The investigation consisted of field survey on the living environment, collection of the pharyngeal swabs from co-exposed individuals, anal swabs from the suspected animals, and environmental samples (including pigeon loft and ventilation shafts). Then all samples were subjected to nucleic acid detection of Chlamydia psittaci. Results The patient presented with fever, chills and productive cough. After treatment failure by self-medication, the patient was admitted to a hospital, and confirmed with psittacosis by metagenomic next-generation sequencing. The investigation demonstrated that the patient was living on the 18th floor, where carrier pigeons were intensively bred on the 19th floor rooftop. The ventilation duct beneath the pigeon loft was found damaged, and the environmental samples revealed positive results from pigeon feces swabs and indeterminate positivity from ventilation duct defects. No suspected cases were identified. Conclusion The event in this report was suspected to be caused by carrier pigeons raised on the roof of residents and transmitted through the ventilation system. Recommendations include enhanced regulation of informal poultry breeding facilities in residential areas to mitigate zoonotic transmission risks of Chlamydia psittaci.

Key words: Chlamydia psittaci, Epidemiological investigation, Environment contamination, Ventilation shaft, Chengdu City