Parasitology

Research Article

Impact of temporal changes and host factors on the genetic structure of a population of Opisthorchis viverrini sensu lato in Khon Kaen Province (Thailand)

W. SAIJUNTHAa1, P. SITHITHAWORNa2a3 c1, N. B. CHILTONa4, T. N. PETNEYa5, S. KLINBUNGAa6, R. SATRAWAHAa1, J. P. WEBSTERa7 and R. H. ANDREWSa8

a1 Walai Rukhavej Botanical Research Institute (WRBRI), Mahasarakham University, Mahasarakham 44150, Thailand

a2 Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand

a3 Liver Fluke and Cholangiocarcinoma Research Center (LFCRC), Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand

a4 Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada

a5 Institute of Zoology 1: Ecology and Parasitology, University of Karlsruhe, Kornblumen Strasse 13, Karlsruhe, Germany

a6 National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand

a7 Department of Infectious Disease Epidemiology, Imperial College Faculty of Medicine, Norfolk Place, London W2 1PG, UK

a8 School of Pharmacy and Medical Sciences, University of South Australia, GPO Box 2471, Adelaide, SA 5001, Australia

SUMMARY

The population genetics of 317 individual Opisthorchis viverrini from Khon Kaen Province Thailand, from 4 different years and 4 cyprinid fish species was examined using multilocus enzyme electrophoresis of enolase (Enol), phosphoglucomutase (Pgm) and triose phosphate isomerase (Tpi). Allele and genotype frequencies for Enol and Pgm were consistent irrespective of year or host species. No heterozygote deficiency was detected for Enol. Significant heterozygote deficiencies were detected in 3 of 4 years for Pgm. For Tpi, allele frequencies of the most common allele and genotype frequency varied between years and among individuals from different host species. Heterozygote deficiencies for Tpi were detected in 2 years. No significant heterozygous deficiencies were detected among O. virerrini from different fish species in 2005, except at Pgm and Tpi from Puntioplites protozsron. There was no statistical significance in pairwise FST values between O. viverrini from Cyclocheilichthys armatus in different years or different host species in 2005. Significant departures from Hardy-Weinberg expectations and a high rate of gene flow in a population of O. viverrini are discussed in terms of self- and cross-fertilisation, natural selection, non-random mating, the Wahlund effect, presence of null alleles, intensity of infection, biology and ecology of their intermediate cyprinid hosts.

(Received February 19 2009)

(Revised April 02 2009)

(Accepted April 02 2009)

(Online publication June 15 2009)

Correspondence:

c1 Corresponding author: Department of Parasitology and Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. Tel: +66 43348387. Fax: +66 43202475. E-mail: paib_sit@kku.ac.th

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