title: High reinfection rate after preventive chemotherapy for fishborne zoonotic trematodes in Vietnam.
abstract: BACKGROUND
  The World Health Organization aims for complete morbidity control of fishborne zoonotic trematodes (FZT) in endemic areas by 2020. The main intervention tool for achieving this goal is regular use of preventive chemotherapy by offering praziquantel to those at risk in endemic areas. The purpose of this study was to investigate the effectiveness of preventive chemotherapy to control FZT in an endemic area in Northern Vietnam.
  
  
  RESULTS
  We followed a cohort of 396 people who fulfilled the criteria for receiving preventive chemotherapy. Stool samples were examined by Kato-Katz technique for the presence of trematode eggs before, and two, 16, 29 and 60 weeks after preventive chemotherapy. The prevalence of trematode eggs in stool was 40.2% before, 2.3% two weeks after and increased to a cumulative prevalence of 29.8% sixty weeks after preventive chemotherapy.
  
  
  CONCLUSIONS
  The effectiveness of preventive chemotherapy as a main component in control of FZT is not well documented in most endemic areas. We found a high reinfection rate within the first year after preventive chemotherapy. Since these trematodes are zoonoses, preventive chemotherapy may not have sufficient impact alone on the transmission to have a lasting effect on the prevalence. Animal reservoirs and farm management practices must be targeted to achieve sustainable control of fishborne zoonotic trematode infections, hence control programs should consider a One Health approach.
authors.affiliation: Department for Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Tore
authors.initials: T
authors.lastname: Lier
authors.affiliation: Department for Parasitology, National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
authors.forename: Dung Trung
authors.initials: DT
authors.lastname: Do
authors.affiliation: Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Maria Vang
authors.initials: MV
authors.lastname: Johansen
authors.affiliation: Department for Parasitology, National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
authors.forename: Thi Hop
authors.initials: TH
authors.lastname: Nguyen
authors.affiliation: Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Dalsgaard
authors.affiliation: Department for Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Anne Mette
authors.initials: AM
authors.lastname: Asfeldt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D018890:Chemoprevention; D002648:Child; D005243:Feces / Q000469:parasitology; D005260:Female; D005399:Fishes / Q000469:parasitology; D005517:Foodborne Diseases / Q000188:drug therapy / Q000453:epidemiology* / Q000469:parasitology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010270:Parasite Egg Count; D011223:Praziquantel / Q000627:therapeutic use; D015995:Prevalence; D012008:Recurrence; D014200:Trematoda; D014201:Trematode Infections / Q000188:drug therapy* / Q000453:epidemiology*; D014744:Vietnam / Q000453:epidemiology; D055815:Young Adult; D015047:Zoonoses / Q000188:drug therapy / Q000453:epidemiology* / Q000469:parasitology
chemical_list: D011223:Praziquantel