Epidemiological Analysis of Foodborne Botulism Outbreaks - China, 2004-2020

Foodborne botulism is a rare, potentially fatal illness resulting from the ingestion of foods contaminated with preformed botulinum neurotoxin types A, B, E, or F, produced by Clostridium botulinum. The descriptive epidemiology of foodborne botulism outbreaks in China during 2004-2020 was performed to inform public health response strategies.

Data from 22 of 31 provincial-level administrative divisions (PLADs) of the National Foodborne Disease Outbreaks Surveillance System during 2004-2020 and Embase, China National Knowledge Infrastructure (CNKI), Wanfang Data, and Chinese Science and Technique Journals (CQVIP) from January 2004 to December 2020 to identify indexed publications in the Chinese literature using the following search terms "botulism," or "botulinum toxin," or "Clostridium botulinum." The number and proportion of outbreaks, illnesses, and deaths by PLAD, food types, and contributing factors were calculated.

During 2004-2020, a total of 80 foodborne botulism outbreaks occurred in China, involving 386 illnesses and 55 deaths; most outbreaks were reported between June and August, with a sharp peak in January; 22 out of 31 PLADs reported foodborne botulism outbreaks, Xinjiang reported the largest number of outbreaks (20), followed by Qinghai (13); the most commonly implicated foods were home-prepared traditional processed stinky tofu and dried beef, accounting for 51.25% events. Improper processing and improper storage in contributing factors accounted for 77.50% outbreaks. Initial misdiagnosis occurred in 27.50% of cases.

Outbreaks of foodborne botulism had a high case-fatality rate. Targeted food safety and popularization education to farmers and herdsmen in Xinjiang and Qinghai related to botulism prevention should be carried out, and timely outbreak investigation and hospital surge capacity should be improved.