An investigation on a cluster epidemic of psittacosis related to a flower and bird market in Shenzhen city

Abstract

Objective To report an investigation on a cluster epidemic of psittacosis related to a flower and bird market in Shenzhen city and to provide reference for the prevention and control of psittacosis epidemic. Methods The data on demographics, clinical and laboratory test were collected for nine psittacosis cases seeking medication at three hospitals in Shenzhen city, Guangdong province during February 8 – April 10, 2021. The information about onsite investigations on cases′ home, involved shops and detections on birds′ biological specimens and environmental samples for Chlamydia psittaci were also collected. According to previous studies, clustering cases were confirmed based on their clinical symptoms, laboratory tests including metagenomic next-generation sequencing (mNGS)，and exposure history (shopping, working or living in places within 300 meters around the flower and bird market with collected specimens positive for Chlamydia psittaci). Results The mean age of the 9 cases were 37.4 years and 5 of the cases were females and 6 of the cases were unemployed or retired. The majority of the cases occurred between February 15 and March 8, 2021. All the 7 symptomatic adult cases manifested high fever, chills, and headache and 5 of them reported fatigue and muscle pain; 6 of them had manifestation of left lung inflammation in chest computed tomography (CT). The two young child cases showed no obvious clinical symptoms and chest CT manifestation. Of the 9 cases, 8 reported the history of buying parrots at the flower and bird market. The interval between the bird purchases and disease onsets was 16 – 40 days, with an average of 28 days. The Chlamydia psittaci positive rate of parrot anal swabs collect from parrots at 3 shops in the flower and bird market was 43.44% (26/60). There was a case without parrot breeding history and a case with a very long interval between bird purchase and onset (> 250 days). Conclusion The clustering psittacosis epidemic was related to the infection of parrots in a flower and bird market, and the possibility of the infection being transmitted from wild birds could not be ruled out.

Keywords

• psittacosis
• cluster epidemic
• flower and bird market
• wild bird infection