Phylogeographic genetic variation of Indoplanorbis exustus (Deshayes, 1834) (Gastropoda: Planorbidae) in South and Southeast Asia
Weerachai Saijuntha,
Chairat Tantrawatpan,
Takeshi Agatsuma,
R.P.V. Jayanthe Rajapakse,
K.J.K. Karunathilake,
Warayutt Pilap,
Wittaya Tawong,
Trevor N. Petney,
Ross H. Andrews
Affiliations
Weerachai Saijuntha
Walai Rukhavej Botanical Research Institute, Mahasarakham University, Maha Sarakham 44150, Thailand
Chairat Tantrawatpan
Division of Cell Biology, Department of Preclinical Sciences, Faculty of Medicine, and Center of Excellence in Stem Cell Research, Thammasat University, Rangsit Campus, Pathum Thani 12120, Thailand; Corresponding author.
Takeshi Agatsuma
Department of Environmental Medicine, Kochi Medical School, Kochi University, Oko, Nankoku, Kochi 783-8505, Japan
R.P.V. Jayanthe Rajapakse
Department of Veterinary Pathobiology, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Peradeniya 20400, Sri Lanka
K.J.K. Karunathilake
Department of Veterinary Pathobiology, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Peradeniya 20400, Sri Lanka
Warayutt Pilap
Walai Rukhavej Botanical Research Institute, Mahasarakham University, Maha Sarakham 44150, Thailand
Wittaya Tawong
Department of Agricultural Science, Faculty of Agriculture, Natural Resources and Environment, Naresuan University, Phitsanulok 65000, Thailand
Trevor N. Petney
Department of Zoology and Paleontology and Evolution, State Museum of Natural History Karlsruhe, Erbprinzenstrasse 13, 76133 Karlsruhe, Germany
Ross H. Andrews
Cholangiocarcinoma Research Institute, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; Faculty of Medicine, Imperial College London, St Mary's Campus, South Wharf Street, London W2 1NY, United Kingdom
The freshwater snail Indoplanorbis exustus play an important role as the sole intermediate host of several medically- and economically-important trematodes, especially zoonotic schistosomes and echinostomes, which can infect and cause diseases in livestock and people. This study aims to explore the mitochondrial cytochrome c oxidase subunit 1 sequence variation of I. exustus collected from new geographical areas; 459 specimens of I. exustus were collected from 43 localities in South and Southeast Asia. The 42 haplotypes (Ie1 – Ie42) we detected were classified into haplogroups I – V. Phylogenetic analyses revealed five major clades, A – E, in concordance with all previous studies. Clade E contained two subclades, E1 (haplogroup I) and E2 (haplogroup II). The most widespread genetic group was subclade E1. Clade A, clade B (haplogroup V), and clade C (haplogroup IV) were found only in South Asia, whereas clade D (haplogroup III) was specifically found in Southeast Asia. In Thailand, I. exustus showed high genetic divergence with 21 haplotypes. Several isolates showed significant genetic differences from others with unique haplotype(s). Hence, we confidently conclude our findings support all previous studies that I. exustus is a species complex with at least four major lineages and five haplogroups. Our additional analyses of 35 samples from Sri Lanka showed these were indeed an independent genetic group as previously found, but they can now be classified as a unique group forming subclade E2 (haplogroup II) of I. exustus sensu lato.
