title: A Large-Scale Community-Based Outbreak of Paratyphoid Fever Caused by Hospital-Derived Transmission in Southern China.
abstract: BACKGROUND
  Since the 1990s, paratyphoid fever caused by Salmonella Paratyphi A has emerged in Southeast Asia and China. In 2010, a large-scale outbreak involving 601 cases of paratyphoid fever occurred in the whole of Yuanjiang county in China. Epidemiological and laboratory investigations were conducted to determine the etiology, source and transmission factors of the outbreak.
  
  
  RESULTS
  A case-control study was performed to identify the risk factors for this paratyphoid outbreak. Cases were identified as patients with blood culture-confirmed S. Paratyphi A infection. Controls were healthy persons without fever within the past month and matched to cases by age, gender and geography. Pulsed-field gel electrophoresis and whole-genome sequencing of the S. Paratyphi A strains isolated from patients and environmental sources were performed to facilitate transmission analysis and source tracking. We found that farmers and young adults were the populations mainly affected in this outbreak, and the consumption of raw vegetables was the main risk factor associated with paratyphoid fever. Molecular subtyping and genome sequencing of S. Paratyphi A isolates recovered from improperly disinfected hospital wastewater showed indistinguishable patterns matching most of the isolates from the cases. An investigation showed that hospital wastewater mixed with surface water was used for crop irrigation, promoting a cycle of contamination. After prohibition of the planting of vegetables in contaminated fields and the thorough disinfection of hospital wastewater, the outbreak subsided. Further analysis of the isolates indicated that the origin of the outbreak was most likely from patients outside Yuanjiang county.
  
  
  CONCLUSIONS
  This outbreak is an example of the combined effect of social behaviors, prevailing ecological conditions and improper disinfection of hospital wastewater on facilitating a sustained epidemic of paratyphoid fever. This study underscores the critical need for strict treatment measures of hospital wastewater and the maintenance of independent agricultural irrigation systems in rural areas.
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang, China.
authors.forename: Meiying
authors.initials: M
authors.lastname: Yan
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Yang
authors.affiliation: Center for Disease Control and Prevention of Yuanjiang County, Yunnan, China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Center for Disease Control and Prevention of Yuxi City, Yunnan, China.
authors.forename: Shukun
authors.initials: S
authors.lastname: Wang
authors.affiliation: Center for Disease Control and Prevention of Yuanjiang County, Yunnan, China.
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Center for Disease Control and Prevention of Yuanjiang County, Yunnan, China.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Pang
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang, China.
authors.forename: Baowei
authors.initials: B
authors.lastname: Diao
authors.affiliation: Center for Disease Control and Prevention of Yuanjiang County, Yunnan, China.
authors.forename: Rusong
authors.initials: R
authors.lastname: Yang
authors.affiliation: International Emerging Infections Program, US Centers for Disease Control and Prevention, Beijing, China; Global Disease Detection Branch, Division of Global Health Protection, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Shuyu
authors.initials: S
authors.lastname: Wu
authors.affiliation: International Emerging Infections Program, US Centers for Disease Control and Prevention, Beijing, China; Global Disease Detection Branch, Division of Global Health Protection, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: John D
authors.initials: JD
authors.lastname: Klena
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D057914:Agricultural Irrigation; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology*; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D000067565:Farmers; D005260:Female; D005516:Food Microbiology; D006761:Hospitals; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010284:Paratyphoid Fever / Q000453:epidemiology*; D012307:Risk Factors; D013997:Time Factors; D014675:Vegetables / Q000382:microbiology*; D062065:Wastewater / Q000382:microbiology; D014871:Water Microbiology; D055815:Young Adult
chemical_list: D062065:Wastewater