Assessment of the risk of cyclosporiasis importation into China

doi:10.12140/j.issn.1000-7423.2026.04.009

Abstract

Abstract:

Objective To systematically assess the risk of cyclosporiasis importation into China during multistage cyclosporiasis outbreaks in the United States in 2026, so as to provide insights into surveillance, early warning, and precision prevention and control of foodborne parasitic diseases. Methods A systematic search was conducted in Chinese and English databases as well as official websites of the United States Centers for Disease Control and Prevention and the United States Food and Drug Administration to collect data pertaining to the prevalence of Cyclospora infections, events of cyclosporiasis outbreaks, epidemiological investigations, and China import requirements for food products. The risk assessment matrix was employed to construct an indicator system for assessment of the risk of cyclosporiasis importation into China, and the likelihood of disease development and severity of consequences were comprehensively evaluated. Results Human Cyclospora infections have been reported across 54 countries in the world, with a pooled global prevalence rate of 3.4%. As of July 13, 2026, a total of 1 645 domestically acquired laboratory-confirmed cases had been reported in the United States. Evidence of human Cyclospora infections has been identified in nine provinces (municipalities) of China, with a pooled detection rate of 0.8% as revealed by PCR assay; however, no routine surveillance system has been established. The Kendall’s coefficients of concordance were 0.725 for likelihood of cyclosporiasis development (P < 0.001) and 0.796 for severity of consequences (P < 0.001), based on two rounds of expert consultations. Weighted scoring indicated that the likelihood of disease development was classified as Level C (possible) and the severity of consequences as Level 2 (minor). A comprehensive analysis with a risk assessment matrix revealed that the overall risk of cyclosporiasis importation into China was moderate. The risk associated with the specific implicated food chain was low, as Mexico-produced head lettuce lacked market access authorization for export to China and no relevant trade records were identified. By contrast, the risk associated with imported fresh produce and products sharing origins, suppliers, or processing links with United States markets was assessed as moderate to high. Conclusion The specific implicated food chain from the current United States outbreak poses a low risk of cyclosporiasis importation into China; however, there is a potential risk for shared-source contamination along global fresh produce supply chains, and China is not non-endemic for this disease. Dynamic surveillance of imported fresh produce and products linked to shared supply chains and improvements in domestic surveillance systems and supply chain traceability capacity are recommended.

Key words: Cyclosporiasis, Importation risk, Risk assessment, Foodborne parasitic disease

CLC Number:

R531

XIA Shang, XUE Jingbo, HAO Yuwan, LI Zhen, TIAN Tian, NI Haobo, SHEN Yujuan, ZHENG Bin, LI Shizhu. Assessment of the risk of cyclosporiasis importation into China[J]. CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES, 2026, 44(4): 517-524.

Figures/Tables 6

Table 1

Table 2

Major historical pandemics in the world

年份 Year	国家/地区 Country/Region	病例数/情况 No. cases/conditions	主要暴露或流行病学结论 Main exposure or epidemiological findings			参考文献 References
1996	美国、加拿大 United States, Canada	1 465	与危地马拉进口覆盆子相关，是北美标志性跨国暴发 An iconic North American transnational outbreak linked to raspberries imported from Guatemala			[2]
1997	美国、加拿大 United States, Canada	1 012	再次与危地马拉进口覆盆子相关 Once again, regarding raspberries imported from Guatemala			[3]
2010	澳大利亚出发的两次邮轮航程 Two cruise voyages departing from Australia	266例，其中73例实验室确诊 266 cases, 73 laboratory-confirmed	疑与生菜有关，提示旅行团和集中供餐场景可形成聚集暴露 Suspected link to lettuce; indicating clustered exposure in tour groups and centralized catering settings			[4]
2013	美国多州 Several U.S. states	631例实验室确诊 631 laboratory-confirmed	部分病例与墨西哥产沙拉原料相关 Some cases linked to salad ingredients produced in Mexico			[5-7]
2014	美国19州 19 U.S. states	304例确诊 304 confirmed cases	春夏季国内获得性病例增加 Increased domestically acquired cases in spring and summer			[8]
2015	美国31州 31 U.S. states	546例确诊 546 confirmed cases	与进口新鲜农产品有关的聚集性事件持续出现 Cluster outbreaks linked to imported fresh agricultural products continue to occur			[8]
2015	英国、加拿大返境 Returning from the United Kingdom and Canada	英国79例、加拿大97例 79 cases in the United Kingdom, 97 cases in Canada	均与墨西哥Riviera Maya地区旅行相关 All linked to travel in Mexico’s Riviera Maya region			[9]
2016	美国得克萨斯州 Texas, U.S.	聚集性病例 Cluster of cases	餐厅相关，流行病学证据提示与凉拌卷心菜和胡萝卜有关 Related torestaurants; epidemiological evidence linking to coleslaw and carrots			[8]
2017	美国 United States	1 065	其中得州38例与青葱有关；多数病例未能明确食品来源 38 cases in Texas linked to green onions; food source unidentified for most cases			[10-11]
2018	美国4州 4 U.S. states	250例实验室确诊 250 laboratory-confirmed	与含西兰花、花椰菜、胡萝卜和莳萝蘸酱的预包装蔬菜托盘有关；8例住院 Related to prepackaged vegetable trays containing broccoli, cauliflower, carrots, and dill dip; 8 hospitalizations			[12]
2018	美国16州 16 U.S. states	511例实验室确诊 511 laboratory-confirmed	与麦当劳供应的沙拉有关；24例住院。未使用的长叶生菜-胡萝卜混合包装中检出环孢子虫 Linked to salads supplied by McDonald’s; 24 hospitalizations. Cyclospora detected in unopened packages of romaine lettuce and carrot mix			[12]
2018	美国 United States	2 299例实验室确诊 2 299 laboratory-confirmed	年度内获得性病例显著增多，多起食品相关聚集事件并存 A significant increase in cases acquired during the year, with multiple food-related outbreaks occurring simultaneously.			[12]
2019	美国11州 11 U.S. states	205例实验室确诊 205 laboratory-confirmed	与墨西哥进口新鲜罗勒相关 Regarding imports of fresh basil from Mexico			[13]
2019	美国 United States	2 408例报告病例 2 408 reported cases	超过2018年，为当时美国年度报告病例高点 Exceeding the 2018 figure, which marked the peak in reported cases in the U.S. that year			[14]
2020	美国13州 13 U.S. states	690	与袋装沙拉相关；涉及冰山生菜、红甘蓝和胡萝卜等原料。污染源未能完全锁定，但相关灌溉水渠检出环孢子虫 Related to bagged salads;involving ingredients such as iceberg lettuce, red cabbage and carrots. Source of contamination not fully identified; Cyclospora detected in associated irrigation canals			[15]
2020	美国 United States	1 441例实验室确诊 1 441 laboratory-confirmed	年度报告病例仍维持高位 Annual reported cases remaining at high levels			[16]
2021	美国 United States	1 020例实验室确诊 1 020 laboratory-confirmed	涉及36州及1个辖区；调查两起多州聚集事件，共170例，未锁定具体食品 Involving 36 states and 1 territory; investigating two multi-state outbreaks totaling 170 cases, specific food item unidentified			[17]
2021	加拿大 Canada	75例非旅行相关病例 75 non-travel-related cases		春夏季增加，未确定共同污染来源 Increases observed in spring and summer; common source of contamination not identified	[18]
2022	加拿大 Canada	325例非旅行相关病例 325 non-travel-related cases		主要分布于安大略省（260例）、魁北克（57例）；未明确共同食品来源 Predominantly in Ontario (260 cases) and Quebec (57 cases); common food source not identified	[18]
2022	美国佛罗里达州 Florida, U.S.	513，其中486例实验室确诊 513, 486 laboratory-confirmed		较2021年的254例增加1倍 Doubling from 254 cases in 2021	[19]
2023	美国阿拉巴马州 Alabama, U.S.	47		墨西哥风味餐厅相关；病例对照研究显示香菜为最可能食品，追溯至墨西哥来源供应链 Linked to Mexican-style restaurants; case-control studies indicate cilantro as the most probable food vehicle, traced to supply chains originating in Mexico	[20]
2023	加拿大 Canada	398例非旅行相关病例 398 non-travel-related cases		安大略328例、魁北克46例；来源未明 328 cases in Ontario and 46 in Quebec; source unknown	[18]

Table 2

Table 3

Table 4

Indicators and weights for assessing the risk of cyclosporiasis importation into China

一级指标 First-grade index	一级权重 First-weight	二级指标 Second-grade index	二级权重 Second-weight
传染源 Source of infection	0.432	近3年本地感染病例情况 Local cases in the past three years	0.099
		近3年输入性病例情况 Imported cases in the past three years	0.118
		近3年国外感染病例情况 Foreign cases in the past three years	0.034
		国外流行区与我国交往密切程度 The relationship between foreign endemic areas and our country	0.084
		美国高风险食品与我国贸易往来密切程度 The extent of trade between the United States and China in high-risk foods	0.096
传播因素 Communication factors	0.295	我国环孢子虫本地传播的季节适宜性 Seasonal suitability for local transmission of Cyclospora in China	0.058
		食品供应链跨境污染风险 Risks of cross-border contamination in the food supply chain	0.098
		我国易感人群分布与暴露水平 Distribution and exposure levels of susceptible populations in China	0.082
		环孢子虫卵囊在外界环境中的存活与传播条件 Survival and transmission conditions of Cyclospora oocysts in the external environment	0.055
防控影响因素 Prevention an control factors	0.272	输入性病例或污染食品的截获检测能力 Capacity for detection and interception of imported cases or contaminated food	0.056
		公众对环孢子虫病的认知程度 Public awareness of cyclosporiasis	0.044
		食品安全监测与防控措施的实施力度 Enforcement of food safety surveillance and prevention and control measures	0.066
		医疗机构对环孢子虫病的诊断能力 Diagnostic capacity of medical institutions for cyclosporiasis	0.041
		食源性或水源性寄生虫病监测网络完善程度 Completeness of surveillance network for foodborne or waterborne parasitic diseases	0.063

Table 4

Table 5

Table 6

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指标 Indicators	感染情况 Infection status	结果说明 Result explanation
已报告人体感染国家数 Number of countries with reported human cases	54	分布广泛，但不等同于均存在地方性流行 Wide distribution, not equivalent to endemiceverywhere
报告过暴发的国家数 Number of countries that have reported outbreaks	至少13个 At least 13	暴发多见于监测和病例报告体系较完善的国家 Outbreaks in countries with well-developed surveillance and case reporting systems
全球合并感染率 Global combined infection rate	3.4%（5 636/166 611）	来自42个国家、150项研究的Meta分析 A meta-analysis of 150 studies from 42 countries
非洲合并感染率 Combined infection rate in Africa	5.9%（606/11 068）	各大洲中最高 The highest on each continent
低收入国家合并感染率 Combined infection rate in low-income countries	7.6%（83/921）	高于高收入国家 Higher than in high-income countries
高收入国家合并感染率 Combined infection rate in high-income countries	0.4%（79/17 419）	多为旅行相关病例或进口食品相关暴发 Mostly travel-associated cases or outbreaks linked to imported food

地区 Region	采样时间 Year	调查对象/检测方法 Study population/Testing method	样本量 Sample size	阳性数 No. positive cases	检出率/% Positive rate/%	参考文献 References
福建 Fujian	1995	腹泻患儿；显微镜检查 Children with diarrhea; microscopic examination	1	1	-	[22]
云南 Yunnan	1997—2000	腹泻患者；显微镜检查 Patients with diarrhea; microscopic examination	378	15	4.00	[23]
安徽 Anhui	2001	不同人群；显微镜检查 Different populations; microscopic examination	610	14	2.30	[24]
河南 Henan	2007—2009	医院患者；显微镜检查 Hospital patients; microscopic examination	11 554	81	0.70	[25]
河南 Henan	2011—2015	人群；PCR及多位点分型 Population; PCR and multiplex genotyping	6 579	76	1.20	[26]
上海、江苏 Shanghai, Jiangsu	2011—2015 2019—2021	腹泻患者；PCR Patients with diarrhea; PCR	5 341	13	0.20	[27-28]
上海 Shanghai	2013	腹泻门诊患者；PCR Outpatients with diarrhea; PCR	291	5	1.70	[29]
广西 Guangxi	2015	猴场工作人员及附近村民；PCR Staff at the monkey farm and nearby villagers; PCR	50	5	10.00	[30]
黑龙江 Heilongjiang	2016—2017	特定人群；PCR Specific populations; PCR	601	7	1.20	[31]
浙江 Zhejiang	2019	腹泻门诊患者；PCR Outpatients with diarrhea; PCR	489	3	0.60	[32]

指标 Index	权重 Weight	0分 Score 0	1分 Score 1	2分 Score 2	3分 Score 3	4分 Score 4
传染性 Infectivity	0.220	个案发生 Individual cases	易于控制 Easy to control	较难控制 Difficult to control	很难控制 Very hard to control	传播途径不明、无法控制 The transmission path is unknown and uncontrollable
致病严重程度与致死率 Severity of the disease and mortality rate	0.244	无 None	< 1%	1%~10%	> 10%~50%	> 50%
治疗有效性 Effectiveness of the treatment	0.218	可自愈 Self-healing	很有效 Striking effect	较有效 Not very effective	效果甚微 Little effect	无效 No effect
对社会稳定的影响 Impact onsocialstability	0.161	可忽略 Negligible	较小 Small	中等 Moderate	较大 Sever	很严重 Disastrous
对食品贸易与经济的影响 Impact on food trade and the economy	0.155	可忽略 Negligible	较小 Small	中等 Moderate	较大 Sever	很严重 Disastrous

风险等级 Risk Level	发生可能性 Risk probability	水平1（可忽略） Level 1 (Negligible)	水平2（较小） Level 2 (Little)	水平3（中等） Level 3 (Moderate)	水平4（较大） Level 4 (Severe)	水平5（灾难性） Level 5 (Disastrous)
A	几乎确定 Almostcertainly	H	H	E	E	E
B	很可能 Be likely to	M	H	H	E	E
C	可能 Possible	L	M	H	E	E
D	不太可能 Unlikely	L	L	M	H	E
E	罕见 Rare	L	L	M	H	H