title: Comparison of infectivity, metacercarial burden and host mortality induced by Opisthorchis viverrini sensu lato cercariae from Lao PDR compared with Thailand in cyprinid fish, Barbonymus gonionotus.
abstract: BACKGROUND
  Previous studies indicate that Opisthorchis viverrini sensu lato (s.l.) is a species complex with strong associations to geographical regions, i.e., specific wetlands. The present study was conducted to compare the infectivity, establishment and metacercarial burden and survival of the fish host following exposure to O. viverrini s.l. cercariae isolates from two different river wetlands.
  
  
  METHODS
  Experimental infections were performed by exposing fish (silver barb, Barbonymus gonionotus) individually to 0 (control) and 100 O. viverrini s.l. cercariae originating from the Songkram River wetland in Thailand and the Nam Ngum River wetland, Lao PDR. Metacercarial burden and fish survivals were monitored after infection.
  
  
  RESULTS
  Fish exposed to O. viverrini s.l. cercariae from the Nam Ngum River wetland had significantly greater metacercarial burden and more active motility at 28 and 35 days post infection than those from the Songkram River wetland. The mortality of fish infected with O. viverrini s.l. from the Nam Ngum River wetland was greater than that from the Songkram River wetland (log-rank test, p<0.01).
  
  
  CONCLUSIONS
  The findings in this study provided additional evidence supporting the importance of cryptic species of O. viverrini s.l. and it has implications for parasite transmission dynamics, life cycle success and disease ecology.
authors.affiliation: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Kulthida
authors.initials: K
authors.lastname: Kopolrat
authors.affiliation: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand Cholangiocarcinoma Screening and Care Program (CASCAP), Khon Kaen University, Khon Kaen 4000, Thailand paibsit@gmail.com paib_sit@kku.ac.th.
authors.forename: Paiboon
authors.initials: P
authors.lastname: Sithithaworn
authors.affiliation: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Nadda
authors.initials: N
authors.lastname: Kiatsopit
authors.affiliation: Faculty of Veterinary Science (Establishment Project), Prince of Songkla University, Songkhla 90110, Thailand.
authors.forename: Opal
authors.initials: O
authors.lastname: Pitaksakulrat
authors.affiliation: Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Smarn
authors.initials: S
authors.lastname: Tesana
authors.affiliation: Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand Cholangiocarcinoma Screening and Care Program (CASCAP), Khon Kaen University, Khon Kaen 4000, Thailand Imperial College London, Faculty of Medicine, St Mary's Campus, South Wharf Street, London W2 1NY. UK.
authors.forename: Ross H
authors.initials: RH
authors.lastname: Andrews
authors.affiliation: Cholangiocarcinoma Screening and Care Program (CASCAP), Khon Kaen University, Khon Kaen 4000, Thailand Institute of Zoology 1: Ecology and Parasitology, Karlsruhe Institute of Technology, Kornblumen Strasse 13, Karlsruhe, Germany.
authors.forename: Trevor N
authors.initials: TN
authors.lastname: Petney
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000469:parasitology*; D005393:Fish Diseases / Q000401:mortality / Q000469:parasitology*; D007812:Laos / Q000453:epidemiology; D058488:Metacercariae / Q000254:growth & development; D009889:Opisthorchiasis / Q000453:epidemiology / Q000401:mortality / Q000662:veterinary*; D009891:Opisthorchis / Q000302:isolation & purification / Q000472:pathogenicity*; D045483:Rivers; D013785:Thailand / Q000453:epidemiology; D053833:Wetlands
keywords: Aquaculture fish; Barbonymus gonionotus; Cryptic species; Metacercariae; Opisthorchis viverrini; Species complex