A Large Acute Gastroenteritis Outbreak Associated with Both Campylobacter coli and Human Sapovirus - Beijing Municipality, China, 2021

What is already known about this topic? Campylobacter is a significant foodborne pathogen that leads to global outbreaks of acute gastroenteritis (AGE) usually affecting less than 30 individuals. Human sapovirus (HuSaV) is an enteric virus responsible for sporadic cases and outbreaks of AGE worldwide. In a study conducted in Beijing, HuSaV detection ranked second after norovirus. What is added by this report? We present a discussion of the first large-scale outbreak of AGE caused by both Campylobacter coli (C. coli) and HuSaV. The outbreak involved a total of 996 patients and exhibited two distinct peaks over a period of 17 days. Through case-control studies, we identified exposure to raw water from a secondary water supply system as a significant risk factor. Among 83 patients, 49 samples tested positive for C. coli, 39 samples tested positive for HuSaV, and 27 samples tested positive for both pathogens using real-time polymerase chain reaction detection. Furthermore, whole-genome sequencing of 17 C. coli isolates obtained from 17 patients revealed that all isolates belonged to a highly clonal strain of C. coli. What are the implications for public health practice? Outbreaks of AGE resulting from multiple pathogen infections warrant increased attention. This report emphasizes the significance of ensuring the safety of drinking water, particularly in secondary supply systems.