title: Case-control study of diarrheal disease etiology in individuals over 5 years in southwest China.
abstract: BACKGROUND
  Acute diarrhea is one of the major public health problems worldwide. Most of studies on acute diarrhea have been made on infants aged below 5 years and few efforts have been made to identify the etiological agents of acute diarrhea in people over five, especially in China.
  
  
  METHODS
  271 diarrhea cases and 149 healthy controls over 5 years were recruited from four participating hospitals between June 2014 and July 2015. Each stool specimen was collected to detect a series of enteric pathogens, involving five viruses (Rotavirusgroup A, RVA;Norovirus, NoV;Sapovirus, SaV;Astrovirus, As; andAdenovirus, Ad), seven bacteria (diarrheagenicEscherichia coli, DEC; non-typhoidalSalmonella, NTS;Shigellaspp.; Vibrio cholera;Vibrio parahaemolyticus;Aeromonasspp.; andPlesiomonasspp.) and three protozoa (Cryptosporidiumspp.,Giardia lamblia, G. lamblia, andBlastocystis hominis, B. hominis). Standard microbiological and molecular methods were applied to detect these pathogens. Data was analyzed using Chi square, Fisher-exact tests and logistic regressions.
  
  
  RESULTS
  The prevalence of at least one enteric pathogen was detected in 29.2% (79/271) acute diarrhea cases and in 12.1% (18/149) in healthy controls (p< 0.0001). Enteric viral infections (14.4%) were the most common in patients suffering from acute diarrhea, followed by bacteria (13.7%) and intestinal protozoa (4.8%). DEC (12.5%) was the most common causative agent in diarrhea cases, followed by NoV GII (10.0%), RVA (7.4%) andB. hominis(4.8%). The prevalence of co-infection was statistically higher (p= 0.0059) in the case group (7.7%) than in the healthy control (1.3%). RVA-NoV GII (3.0%) was the most common co-infection in symptomatic cases.
  
  
  CONCLUSIONS
  DEC was the most predominant pathogen in diarrhea cases, but it was largely overlooked because the lack of laboratory capacities. Because of the high prevalence of co-infections, it is recommended the urgent development of alternative laboratory methods to assess polymicrobial infections. Such methodological improvements will result in a better prevention and treatment strategies to control diarrhea illness in China.
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Shun-Xian
authors.initials: SX
authors.lastname: Zhang
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Yang
authors.affiliation: Yunnan Provincial Center for Disease Control and Prevention, Kunming, 650022 People's Republic of China.
authors.forename: Wen-Peng
authors.initials: WP
authors.lastname: Gu
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Ai
authors.affiliation: Center for Environmental and Marine Studies (CESAM), Departamento de Biología, Universidade de Aveiro, Aveiro, Portugal.|Servei d´Ecopatologia de Fauna Salvatge (SEFaS), Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Serrano
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Pin
authors.initials: P
authors.lastname: Yang
authors.affiliation: Department of parasitology, College of Medicine, Soochow University, Suzhou, 215123 People's Republic of China.
authors.forename: Xia
authors.initials: X
authors.lastname: Zhou
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Shi-Zhu
authors.initials: SZ
authors.lastname: Li
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Shan
authors.initials: S
authors.lastname: Lv
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Zhi-Sheng
authors.initials: ZS
authors.lastname: Dang
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Jun-Hu
authors.initials: JH
authors.lastname: Chen
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Li-Guang
authors.initials: LG
authors.lastname: Tian
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Jia-Xu
authors.initials: JX
authors.lastname: Chen
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025 People's Republic of China.|Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 20025 People's Republic of China.
authors.forename: Xiao-Nong
authors.initials: XN
authors.lastname: Zhou
keywords: Acute diarrhea; Bacteria; Co-infection; Enteric protozoa; Virus