Molecular Epidemiology of Type F Clostridiumperfringens Among Diarrheal Patients and Virulence-Resistance Dynamics — 11Provinces, China, 2024

Zelin Yan^1,&; Hanyu Wang^2,&;Yanyan Zhu¹; Xuejin Wang^1,3; Yongning Wu⁴;Yang Wang^2,#; Rong Zhang^1,#

1. Department of Clinical Laboratory, The SecondAffiliated Hospital, Zhejiang University School of Medicine, Hangzhou City,Zhejiang Province, China

2. Beijing Advanced Innovation Center for Food Nutritionand Human Health, College of Veterinary Medicine, China AgriculturalUniversity, Beijing, China

3. Key Laboratory of Medical Genetics of ZhejiangProvince, Key Laboratory of Laboratory Medicine, Ministry of Education, Schoolof Laboratory Medicine and Life Sciences, Wenzhou Medical University, WenzhouCity, Zhejiang Province, China

4. Key Laboratory of Food Safety Risk Assessment,Ministry of Health and China National Center for Food Safety Risk Assessment,Beijing, China

&Joint first authors.

Corresponding authors: YangWang, wangyang@cau.edu.cn; Rong Zhang, zhang-rong@zju.edu.cn.

TypeF Clostridium perfringens representsa significant pathogen in human gastrointestinal diseases, primarily throughits cpe gene encoding enterotoxinCPE. This investigation examined the prevalence, antimicrobial resistancepatterns, and genetic characteristics of type F C. perfringens within the Chinese population. The study analyzed2,068 stool samples collected from 11 provincial hospitals in 2024.Antimicrobial susceptibility testing was conducted following CLSI guidelines,while whole-genome sequencing provided detailed genetic profiles. Evolutionaryrelationships and clonal transmission patterns were investigated throughphylogenetic and genetic environment analyses. The prevalence of type F C. perfringens was 2.38%, with isolatespredominantly identified in human clinical samples and higher detection ratesin gastroenterology departments. Notably, 47.1% of isolates demonstrated highresistance to metronidazole, while all exhibited intermediate resistance toerythromycin. Phylogenetic analysis revealed high similarity among isolatesfrom patients within the same province (SNPs <100), and genetic environmentanalysis indicated potential horizontal gene transfer between animal and humanstrains. This investigation predominantly identified type F C. perfringens in human clinical cases,with sporadic detection in pets and food products. These findings highlight theemergence of type F C. perfringensoutbreaks among diarrheal patients, emphasizing the necessity for targetedinterventions as virulence factors increase.

F型产气荚膜梭菌的分子流行病学分析聚焦腹泻患者及其毒力与耐药情况的动态研究— 11省份，中国，2024年

严泽琳^1,&；王汉宇^2,&；竺燕燕¹；王雪瑾^1,3；吴永宁⁴；汪洋^2,#；张嵘^1,#

1. 浙江大学医学院附属第二医院，杭州市，浙江省，中国；

2.兽医公共卫生安全全国重点实验室，动物医学院，中国农业大学，北京，中国；

3. 浙江省医学遗传学重点实验室，检验医学教育部重点实验室，检验医学院生命科学学院，温州医科大学，温州市，浙江省，中国；

4. 国家食品安全风险评估中心，北京，中国。

&：共同第一作者。

^# 通信作者:张嵘, zhang-rong@zju.edu.cn；汪洋,wangyang@cau.edu.cn。

F型产气荚膜梭菌是一种与人类胃肠道疾病相关的重要病原体，主要通过编码肠毒素CPE的cpe基因致病。本研究旨在探讨F型产气荚膜梭菌在中国人群中的流行情况、抗菌药物耐药性以及遗传特征。2024年，本实验共采集了来自11家省级医院的2,068份粪便样本。抗菌药物敏感性测试遵循CLSI指南进行，使用全基因组测序分析遗传特征。通过系统发育学和遗传环境分析，探索菌株的进化关系及克隆传播情况。F型产气荚膜梭菌的检出率为2.38%。菌株主要来源于人体样本，胃肠病科的检出率较高。47.1%的菌株对甲硝唑表现出高度耐药性，所有菌株对红霉素表现为中等耐药性。系统发育分析表明，来自同一省份患者的菌株具有高度相似性（SNPs < 100）；遗传环境分析提示可能存在动物与人类菌株之间的水平基因转移。本研究主要在腹泻患者中检测到F型产气荚膜梭菌，但仅在宠物或食品中偶见。研究结果强调了F型产气荚膜梭菌在腹泻患者中暴发的风险，突显了随着毒力因子增强，采取针对性措施控制该病原体的必要性。

For more information: https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.013

Prevalence and Risk Factors ofMultidrug-Resistant Enterococcal Infection in Clinical Dogs and Cats —China, 2018–2021

Xukun Dang^1,2,&; Junyao Jiang^3,&; Siyu Chen^4,5; Wei Huang⁵;Ying Jiao⁵; Siying Wang⁵; Zhiyu Zou^1,2; Qi An⁴;Yu Song⁴; Lu Wang^1,2; Run Fan^1,2; Dejun Liu^1,2;Stefan Schwarz^1,6,7; Jianzhong Shen^1,2; Zhaofei Xia^4,5;Yang Wang^1,2; Yanli Lyu^4,5,#; Shizhen Ma^1,2,#

1. Key laboratory ofAnimal Antimicrobial Resistance Surveillance, Ministry of Agriculture and RuralAffairs, College of Veterinary Medicine, China Agricultural University,Beijing, China

2. National KeyLaboratory of Veterinary Public Health Safety, College of Veterinary Medicine,China Agricultural University, Beijing, China

3. TechnologyInnovation Center for Food Safety Surveillance and Detection (Hainan), SanyaInstitute of China Agricultural University, Sanya City, Hainan Province, China

4. Department ofClinical Veterinary Medicine, College of Veterinary Medicine, ChinaAgricultural University, Beijing, China

5. BeijingZhongnongda Veterinary Hospital Co., Ltd., Beijing, China

6. Institute ofMicrobiology and Epizootics, Centre for Infection Medicine, School ofVeterinary Medicine, Freie Universität Berlin, Berlin, Germany

7. Veterinary Centrefor Resistance Research, School of Veterinary Medicine, Freie UniversitätBerlin, Berlin, Germany.

&Joint first authors.

#Corresponding author: Yanli Lyu, luyanli@cau.edu.cn; Shizhen Ma, shizhenma@cau.edu.cn.

This study aimed to investigate the prevalence andrisk factors of enterococcal infections in dogs and cats at animal hospitals,as well as to dissect the molecular characteristics and assess the publichealth relevance of linezolid-resistant enterococci. Clinical samples were collected from2,247 dogs and 950 cats at Chinese animal hospitals during 2018 to 2021 andtested for Enterococcus spp.isolates. Antimicrobial susceptibility testing of enterococci was conducted following CLSI guidelines,and data was analyzed using WHONET. Risk factors for multidrug-resistant (MDR)enterococcal infections were assessed through univariate and logisticregression analyses. In addition, whole genome sequencing oflinezolid-resistant Enterococcus spp. was performed, with genomicfeatures and phylogenetic relationships analyzed using various bioinformaticstools. Enterococci were detected in 14.39% (n=460) of samples, withascites showing the highest occurrence (24/100, 24.00%). Among 477 identified Enterococcusspp., Enterococcusfaecium (n=217, 45.49%) and Enterococcus faecalis (n=207,43.40%) predominated. E. faeciumdisplayed higher resistance rates (7.83–86.75%) to daptomycin, rifampin,doxycycline, and amoxicillin-clavulanate than E. faecalis (1.14–63.43%). MDR enterococcal infections correlatedwith urinary tract catheterization history (p=0.03) and hospitalizationduration (p=0.04). Notably, 11 E.faecalis and eight E. faecium exhibited linezolid resistance andcarried optrA gene. Analysis of 148 optrA-positive Enterococcusisolates (19 from thisstudy and 129 from databases) revealed that E.faecium of pet origin from this study exhibited close genetic relationshipsonly to pet isolates, while seven pet-derived E. faecalis presented high genetic similarity (19–94 core genomeSNPs) with isolates from pets, humans, farm animals, beef, and plants. Tomitigate enterococcal infections, proper aseptic protocols for invasiveprocedures and reduced hospitalization time in pet clinics are recommended. Ofparticular concern are linezolid-resistant E.faecalis infections due to potential pets-human transmission risks.

宠物临床中犬、猫多重耐药肠球菌流行和感染风险分析—中国，2018–2021年

党旭堃^1,2,&；蒋君瑶^3,&；陈丝雨^4,5；黄薇⁵；缴莹⁵；王思莹⁵；邹之宇^1,2；安琪⁴；宋昱⁴；王璐^1,2；樊润^1,2；刘德俊^1,2；StefanSchwarz^1,6,7；沈建忠^1,2；夏兆飞^4,5；汪洋^1,2；吕艳丽^4,5,#；马士珍^1,2,#

1. 兽医公共卫生安全全国重点实验室，动物医学院，中国农业大学，北京，中国；

2. 农业农村部动物源细菌耐药性监测重点实验室，动物医学院，中国农业大学，北京，中国；

3. 海南省食品安全监测及检测技术创新中心，中国农业大学三亚研究院，三亚市，海南省，中国；

4. 临床兽医系，动物医学院，中国农业大学，北京，中国；

5. 中国农业大学教学动物医院，北京，中国；

6. 微生物学和动物传染病研究所，兽医学院，柏林自由大学，柏林，德国；

7. 兽用抗生素研究中心，兽医学院，柏林自由大学，柏林，德国。

^&共同第一作者。

^#通信作者：吕艳丽，luyanli@cau.edu.cn；马士珍，shizhenma@cau.edu.cn。

本研究旨在评估我国宠物临床中犬猫肠球菌感染的流行情况和相关风险因素，并阐明利奈唑胺耐药肠球菌的分子特征及其公共卫生风险。2018至2021年，收集2247份犬和950份猫的临床样本，分离肠球菌并检测其对抗菌药物的敏感性。通过单变量和逻辑回归分析评估多重耐药肠球菌感染的风险因素。对利奈唑胺耐药肠球菌进行全基因组测序，分析基因组特征及其与各来源菌的亲缘关系。肠球菌属细菌总检出率是14.39%，腹水样本中检出率最高（24.00%）。在477株分离菌中，屎肠球菌和粪肠球菌是主要菌种（88.89%）。屎肠球菌对达托霉素、利福平和多西环素等多种药物的耐药率高于粪肠球菌。多重耐药肠球菌感染与导尿操作史和住院时间相关。11株粪肠球菌和8株屎肠球菌对利奈唑胺耐药，携带optrA基因。对148株optrA阳性肠球菌（其中129株源自NCBI数据库）分析显示，本研究中的屎肠球菌只与宠物源菌亲缘关系更近，而粪肠球菌与宠物、人、食品动物和环境源菌株有高度遗传相似性，仅有19-94个核心基因组SNP。为降低肠球菌感染的风险，建议宠物医院采取严格的无菌措施并尽量缩短住院时间。鉴于粪肠球菌可能存在宠物向人群的传播风险，对利奈唑胺耐药粪肠球菌感染需特别关注。

For more information:https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.017

Prevalence and Risk Factors ofWaterborne and Foodborne Protozoan Pathogens in Kenya: A One Health Perspective

Joseph Okoth Ogalo^1,2; Chang Cai^3,#;Ziming Han^1,2; Yu Zhang^1,2; Min Yang^1,2

1. StateKey Laboratory of Environmental Aquatic Chemistry, Research Center forEco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China;

2.University of Chinese Academy of Sciences, Beijing, China;

3.College of Veterinary Medicine, Nanjing Agricultural University, Nanjing City,Jiangsu Province, China.

^# Corresponding author: Chang Cai, chang.cai@njau.edu.cn.

Intestinalinfections affect approximately 450 million people globally, predominantlyimpacting children and immunocompromised individuals in low- and middle-incomecountries (LMICs) due to inadequate water, sanitation, and hygiene (WASH)conditions, poverty, malnutrition, and low literacy. In Kenya, the prevalenceof intestinal infections is elevated by warm tropical climates and socioeconomicfactors. This scoping review evaluates the national prevalence, risk factors,and contamination sources of intestinal protozoa in Kenya, using a One Healthapproach to synthesize existing data from various human, animal, andenvironmental studies. A comprehensive literature search identified 292studies, of which 67 met the inclusion criteria, covering the period from 1966to 2024. The review found that most studies utilized stool microscopy, a methodwith limited sensitivity, and largely focused on vulnerable human populations,with minimal investigation into environmental reservoirs. Key protozoaidentified included Entamoeba histolytica,Cryptosporidium, and Giardia, with transmission driven bypoor WASH conditions, environmental factors, and close human-animalinteractions. The findings highlight significant gaps in environmentalsurveillance and suggest the need for a robust, integrated One Health approachto better understand and control protozoan infections in Kenya.

肯尼亚水源和食源性原生动物病原体的流行情况及相关风险因素：基于One Health理念

Joseph Okoth Ogalo^1,2；蔡畅^3,#；韩子铭^1,2；张昱^1,2；杨敏^1,2

1. 环境水质学国家重点实验室，中国科学院生态环境研究中心，北京，中国；

2. 中国科学院大学，北京，中国；

3. 南京农业大学，动物医学院，南京市，江苏省，中国。

^#通信作者:蔡畅，chang.cai@njau.edu.cn。

肠道感染在全球影响约4.5亿人，尤其在低收入和中等收入国家（LMICs）中，对儿童和免疫受损个体的影响尤为显著，主要由水、卫生和环境卫生（WASH）的不足、贫困、营养不良和文盲等因素造成。在肯尼亚，温暖的热带气候和社会经济因素加剧了肠道感染的流行。本文基于“one health”理念，综合现有的人类、动物和环境研究数据，评估了肯尼亚原生动物的全国流行情况、风险因素和污染源等。经过全面的文献检索，共识别出292项研究，其中67项符合纳入标准，纳入文献涵盖了1966至2024年这一时间段。研究发现，大多数纳入的研究采用的粪便显微镜检查方法，尽管该方法灵敏度有限。纳入研究主要集中于脆弱人群，环境相关的研究则较少。识别的主要原生动物包括痢疾阿米巴、隐孢子虫和贾第虫，其传播受到不良的WASH条件、环境因素和人畜密切接触等因素影响。研究结果凸显了肯尼亚地区环境监测的重大缺口，建议加强“one health”理念的实施，以更好地理解和控制肯尼亚的原生动物感染。

For more information:https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.014

A Database on Antibiotics and AntibioticResistance in Wastewater and Solid Waste from Pharmaceutical Industry Based ona Systematic Review

Jingwei Wu^1,2,3; Ziming Han¹; Xiaomin Ma⁴;Ming Su^1,3; Amir Hossein Hamidian⁴; Yu Zhang^1,2,3,#;Min Yang^1,2,3

1. State Key Laboratory ofEnvironmental Aquatic Chemistry, Research Center for Eco-EnvironmentalSciences, Chinese Academy of Sciences, Beijing, China

2. Sino-Danish College,University of Chinese Academy of Sciences, Beijing, China

3. University of ChineseAcademy of Sciences, Beijing, China.

4. Agricultural InformationInstitute, Chinese Academy of Agricultural Sciences, Beijing, China

5. Department ofEnvironmental Science and Engineering, Faculty of Natural Resources, CollegeUniversity of Agriculture & Natural Resources, University of Tehran, Karaj,Iran

^# Corresponding author: Yu Zhang,zhangyu@rcees.ac.cn.

Residual antimicrobial agentsin wastewater and solid waste from antimicrobialmanufacturing facilities can potentially contaminate various environmentalcompartments throughout the production chain. The World Health Organization hasestablished technical guidelines for managing antimicrobial resistance (AMR) inpharmaceutical wastewater and solid waste. However, thescarcity of publicly available data on antimicrobial manufacturing processes,including waste and wastewater treatment protocols, impedes the development ofeffective mitigation strategies. To address this knowledge gap, we developed acomprehensive database documenting antibiotics and antibiotic resistance genes(ARGs) in actual wastewater and solid waste samples, primarily focusing onfermentation residues from microbial fermentation-based antibiotic productionprocesses. Through systematic review methodology, we compiled data fromextensive searches of English-language article databases, including Web ofScience and PubMed. The database encompasses 256 records of antibioticconcentrations measured via three major detection methods, alongside 100records of ARG abundance determined through two detection approaches. It contains data from 270 distinct samples collectedacross 45 fermentation residue treatment systems and 46 wastewater treatmentsystems, derived from 70 published English-language articles spanning 2008 to2024. In operational pharmaceutical facilities, antibiotic concentrationsranged from 82 to 1,663 mg/L in raw wastewater and from 1,000to 10,182 mg/kg dry matter (DM) in antibiotic fermentation residues.Various treatment technologies demonstrated significant reductions in bothantibiotic concentrations and ARG levels within wastewater and fermentationresidues. This database provides the first globalperspective on antibiotic and ARG contamination from antibiotic productionprocesses, supporting AMR management initiatives. It establishes a dynamic,continuously updated platform accessible to researchers and industrystakeholders via the link: https://dash.drwater.net/antiboard/.

基于系统综述的制药废水与固体废物中抗生素及抗生素耐药性数据库

吴静薇^1,2,3；韩子铭¹；马晓敏⁴；苏命^1,3；Amir Hossein Hamidian⁵；张昱^1,2,3,#；杨敏^1,2,3

1. 环境水质学国家重点实验室，生态环境研究中心，中国科学院，北京，中国

2. 中国科学院大学，中丹学院，北京，中国

3. 中国科学院大学，北京，中国

4. 中国农业科学院农业信息研究所，北京，中国

5. 环境科学与工程系，自然资源学院，农业与自然资源学院，德黑兰大学, 卡拉吉，伊朗

^#通信作者：张昱，zhangyu@rcees.ac.cn。

抗菌药生产过程中产生的废水和固体废物残留药物活性成分，可能进入生产或生产链各个环节的环境中，世界卫生组织针对制药行业废水和固废耐药性（AMR）管控已经发布了技术指南。然而，目前缺乏关于抗生素生产过程的公开数据，包括废水和固体废物的处理与管理，这使得制定有效的减缓干预措施变得困难。为弥补这一空白，本文构建了一个聚焦实际废水和固体废物（主要是微生物发酵法生产抗生素的发酵菌渣）中抗生素及耐药基因（ARGs）的数据库。数据库基于系统回顾文献方法，通过对Web of Science以及PubMed等英文文献信息资源进行广泛检索收集数据，包括256条通过三种检测方法获得的抗生素浓度记录；同时包含利用两种检测方法获得的100条耐药基因丰度的记录。数据涵盖了2008年至2024年间70篇公开英文论文的研究成果，包含了来自45个发酵菌渣处理系统和46个废水处理系统的270个特定样本。在实际制药工业中，抗生素生产废水中的残留抗生素浓度范围从82 mg/L到1,663 mg/L，发酵菌渣中的抗生素浓度范围则为1,000 mg/kg干物质（DM）至10,182 mg/kg DM。数据库总结了多种处理技术，经处理后废水和发酵菌渣中的抗生素浓度及耐药基因丰度显著减少。该数据库从全球研究视角初步提供了一个制药行业抗生素及耐药性基因污染概览，旨在为耐药性管理提供支持，并为研究人员和制药行业建立一个动态、持续更新的平台，可以通过链接https://dash.drwater.net/antiboard/访问。

For more information:https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.015

Development of a High-Throughput qPCRAssay for Detecting Waterborne Protozoa and Helminths Across DifferentEnvironmental Media in China

Fuming Duan^1,2;Ziming Han¹; Tiantian Tian³; Huican Zhang^1,4;Min Yang^1,2; Yu Zhang^1,2,4,#

1.State Key Laboratory of Environmental Aquatic Chemistry, Research Center forEco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China;

2.University of Chinese Academy of Sciences, Beijing, China;

3.College of Life Sciences, Henan Agricultural University, Zhengzhou City, HenanProvince, China; 4. Henan Institutes of Advanced Technology, ZhengzhouUniversity, Zhengzhou City, Henan Province, China.

^# Corresponding authors:Yu Zhang: zhangyu@rcees.ac.cn.

The establishment of a high-throughputquantification approach for waterborne pathogenic protozoa and helminths iscrucial for rapid screening and health risk assessment. We developed ahigh-throughput qPCR (HT-qPCR) assay targeting 19 waterborne protozoa and 3waterborne helminths and validated its sensitivity, specificity, andrepeatability. The assay was then applied to test various environmental mediasamples. The HT-qPCR assay's limit of detection (LOD) was 5 × 10²copies/μL DNA, and its specificity was confirmed using Giardia and Cryptosporidiumstandards. Repeatability, assessed through intra- and inter-group experiments,yielded a coefficient of variation (CV) of 1.0%–4.6% and 1.2%–6.4% atconcentrations of 1 × 10⁵ and 1 × 10⁴ copies/μL,respectively. The R²values of the 22 standard curves ranged from 0.983 to 0.998, with amplificationefficiencies between 80% and 107%. In drinking water sources, sludge fromMWTPs, and livestock manure samples, 17 of 22 targets were detected, with Acanthamoeba genus (50.0%), Acanthamoeba castellanii (11.8%), and Enterocytozoon bieneusi (11.8%) showinghigh prevalence. Cryptosporidiumspp., Enterocytozoon bieneusi, and Cyclospora cayetanensis weresimultaneously found in all three sample types. This study presents a usefultool for the rapid detection of waterborne protozoa and helminths in complexenvironmental microbiomes, providing scientific data for monitoring cross-mediatransmission and controlling microbial risk from a One Health perspective.

用于检测不同环境介质中介水传播原虫和蠕虫的高通量qPCR方法

段福明^1,2；韩子铭¹；田甜甜³；张辉灿^1,4；杨敏^1,2；张昱^1,2,4,#

1. 环境水质学国家重点实验室，生态环境研究中心，中国科学院，北京，中国

2. 中国科学院大学，北京，中国

3. 生命科学学院，河南农业大学，郑州，河南省，中国

4. 河南先进技术研究院，郑州大学，郑州市，河南省，中国。

^# 通信作者：张昱，zhangyu@rcees.ac.cn。

本研究旨在建立环境介质中介水传播致病原虫和蠕虫的高通量qPCR方法，用于原虫和蠕虫的快速筛查和健康风险评估。开发了一种针对19种介水传播原虫和3种介水传播蠕虫的高通量qPCR（HT-qPCR）检测方法，验证了其灵敏度、特异性和重复性，并将该方应用于动物-环境-人群相关多种环境介质样本的检测。HT-qPCR方法的检测限为5×10² copies/μL DNA，方法特异性通过贾第鞭毛虫和隐孢子虫标准品得到证实。通过组内和组间实验评估了方法重复性，在浓度为1×10⁵ copies/μL和1×10⁴copies/μL条件下，变异系数（CV）分别为1.0%-4.6%和1.2%-6.4%。22条标准曲线的R²在0.983至0.998之间，扩增效率在80%至107%之间。在饮用水源、市政污水处理厂污泥和畜禽粪便样本中，22个目标物中有17个被检测到，其中棘阿米巴属（50.0%）、卡氏棘阿米巴（11.8%）和结肠小袋纤毛虫（11.8%）的检出率较高。在三种介质中同时检出的有隐孢子虫属、结肠小袋纤毛虫和环孢子虫等。这项研究为复杂环境微生物群落中介水传播原虫和蠕虫的快速检测提供了有力工具，为从“同一健康”的角度监测和管控病原微生物的跨介质传播风险提供了科学数据。

For more information:https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.016

Infection Tracing and Virus GenomicAnalysis of Two Cases of Human Infection with Avian Influenza A(H5N6) — FujianProvince, China, April–May 2024

Yanhua Zhang¹; Jingjing Wu¹;Qi Lin¹; Jianming Ou¹; Xiaoqi Qi¹; YouxianZheng²; Fengping Li²; Yuwei Weng^{1, #}

1. Fujian Provincial Center for DiseaseControl and Prevention, Fujian Provincial Key Laboratory of Zoonosis Research,Fuzhou City, Fujian Province, China;

2. Quanzhou Municipal Center for DiseaseControl and Prevention, Quanzhou City, Fujian Province, China.

^#Corresponding author: Yuwei Weng, wengyuwei@fjcdc.com.cn.

This articleinvestigates two reported cases of human infection with H5N6 avian influenza inQuanzhou City, Fujian Province, from April to May 2024, providing insights forepidemic prevention and risk assessment. We combine field epidemiologicalinvestigations with laboratory testing to accurately trace the outbreak andevaluate the virus's public health risks. The findings suggest that Case A waslikely infected by her own poultry, while Case B contracted the virus from aneighbor's poultry, with no direct or indirect epidemiological link between thetwo cases After 10 days of medical observation, no infections were detectedamong close contacts. Whole-genome analysis indicates that the virus belongs tothe clade 2.3.4.4h, distinct from the currently circulating clade 2.3.4.4bglobally. Except for the MP and NS gene segments, the remaining six genesegments of the viruses collected from the patients exhibit differences;notably, Case B's virus is identical to environmental samples from theneighbor's poultry shed, further ruling out a connection between the cases.Genetic analyses revealed that while the virus maintains its avian hosttropism, it has acquired mutations that may enhance human receptor bindingaffinity, viral replication capacity, pathogenicity, and neuraminidaseinhibitor resistance. Through comprehensive field epidemiologicalinvestigations and laboratory analyses, we identified the infection sources forthese cases and conclusively ruled out human-to-human transmission. However,given the risks associated with viral mutations and their evolution, it iscrucial to enhance monitoring efforts.

两例人感染H5N6禽流感病例的感染调查与病毒全基因组分析 — 福建省，中国，2024年4– 5月

张炎华¹；吴晶晶¹；林琦¹；欧剑鸣¹；齐孝旗¹；郑友限²；李锋平²；翁育伟^1，#

1. 福建省疾病预防控制中心，福建省人兽共患病实验室，福州市，福建省，中国；

2. 泉州市疾病预防控制中心，泉州市，福建省，中国。

^&共同第一作者。

^#通信作者：翁育伟，wengyuwei@fjcdc.com.cn。

本文旨在调查2024年4月至5月在福建省泉州市报告的2例人感染H5N6禽流感病例，为疫情防控和风险评估提供参考依据。本研究运用现场流行病学调查和实验室检测相结合的方法，对疫情进行精准溯源，并评估病毒对公共卫生的风险。调查结果显示，病例A的感染源很可能为自家饲养的家禽，而病例B则来自邻居饲养的家禽，两例病例之间没有直接或间接的流行病学关联。两例病例的密切接触者经10天的医学观察后均未发现感染。病毒全基因组分析分析显示，本次报告的病毒属于2.3.4.4h进化分枝，与当前全球流行的2.3.4.4b不同。除MP和NS基因节段外，2例病例中获取的病毒基因其余6个节段均存在差异；而病例B的病毒基因则与收集自其邻居禽舍的环境样本完全一致，这进一步排除了两例病例之间的感染关系。研究还发现，虽然该病毒保持其对禽类宿主的嗜性，但他们获得了可能增强人类受体结合亲和力、病毒复制能力、致病性和神经氨酸酶抑制剂耐药性的突变。通过全面的现场流行病学调查和实验室分析，我们确定了这些病例的感染来源，并明确排除了人际传播的可能性。然而，考虑到病毒突变和进化带来的风险，加强监测显得尤为重要。

For more information:https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.018