Changes to the life cycle of liver flukes: dams, roads, and ponds.

1 Sripa B, Pairojul C. Cholangiocarcinoma: lessons from Thailand. Curr Opin Gastroenterol 2008; 24: 349–56. 2 Ziegler AD, Andrews RH, Grundy-Warr C, Sithithaworn P, Petney TN. Fighting liverfl ukes with food safety education. Science 2011; 331: 282–83. 3 Asian Development Bank. Report and recommendation of the president to the board of directors on a proposed loan to the Lao People’s Democratic Republic for the Greater Mekong Subregion: Nam Theun 2 hydroelectric project. Asian Development Bank, 2005. 4 FAO. Fishery and aquaculture country profi les: Lao People’s Democratic Republic. Rome: Food and Agriculture Organization. 2010. 5 Bush SR, Kosy S. Geographical distribution of investment in small-scale rural fi sh ponds. Aquacult Econ Manage 2007; 11: 285–311. 6 Ko J. Public participation in integrated water resource management: villages in Lao PDR and the Mekong River Basin. Master’s thesis, Waterloo University, 2006. 7 Asian Development Bank. Report and recommendation of the president to the board of directors on a proposed loan to the Lao People’s Democratic Republic for the Greater Mekong Subregion: Northern Economic Corridor Project. Asian Development Bank, 2002. 8 De Silva S. First culture-based fi sheries growth cycle in Lao PDR is overwhelmingly encouraging. Aquacult Asia 2008; 13: 9–10. 9 Grundy-Warr C, Andrews RH, Sithithaworn P, et al. Raw attitudes, wetland cultures, lifecycles: socio-cultural dynamics relating to Opisthorchis viverrini in the Mekong basin. Int J Parasitol 2012; 61: 65–70. industry. O viverrini infects at least fi ve species of commercially available fi sh: Barbonymus gonionotus, Cirrhinus mrigala, Cyprinus carpio, Ctenopharyngodon idellus, and Hypophthalmichthys molitrix (unpublished). Furthermore, the tiny intestinal fl uke Haplorchis taichui infects 85% of the Laos hatchery and nursery fi sh species—a proportion that is 39% higher than those infected with O viverrini (unpublished). These data suggest that infection before stocking is a likely cause of higher prevalence of O viverrini metacercariae found in fi sh from ponds in Laos than in Thailand. For example, the prevalence of O viverrini in Cyclocheilichthys armatus—a native fi sh that coexists with aquaculture pond species—is tentimes higher in Laos than in Thailand (40% vs 3%), suggesting active and ongoing transmission of the disease after stocking with infected fi sh. These fi ndings show how wellmeaning developments designed to improve livelihoods in the Mekong region threaten to increase an already high prevalence of opisthorchiasis and cholangiocarcinoma. Regulation should be introduced to prevent home garden ponds being stocked with infected fi sh and to exclude O viverrini reservoir hosts such as dogs and cats from the premises of fi sh farms. Advances are also needed in sanitation and education about the risks of eating improperly cooked fi sh. Furthermore, future development projects that aff ect water bodies or natural drainage patterns should be assessed holistically to establish their potential 4 Waterman P, McGann P, Riley M, et al. Applications of advanced genome mapping in the Military Health System polytrauma patient. 49th Annual Meeting of the Infectious Diseases Society of America and the HIV Medicine Association; Boston, MA, USA; Oct 20–23, 2011. Abstract 373. 5 Riley MC, Lee JE, Lesho E, Kirkup BC Jr. Optically mapping multiple bacterial genomes simultaneously in a single run. PLoS One 6: 327085.