Geographic Information System of Fish-borne Parasitic Zoonoses Metacercaria From Water Reservoirs Under His Majesty’s Recommended Project, Phitsanulok, Thailand
要旨Fish-borne infections continue to be a major public health problem, with more than 50 million people infected throughout the world. The watershed development scheme is an extended plan to achieve the objectives of Kwae Noi reservoir under His Majesty’s Recommended Project involving a proper water management for consumption all year round. Adequate water will increase the fertility of these areas and provide a suitable breeding place for various forms of aquatic life including fish. The popularity of uncooked, freshwater fish among the indigenous people in regions endemic for fish borne zoonotic parasites represents a continuing public health concern. Current reports indicate that metacercaria of pathogenic heterophyid trematodes are found in freshwater fish. In this study fish were examined for the presence of metacercariae by pressing or crushing using pairs of plexiglass. The infective stage of larvae in fish or metacercariae was detected using a stereo-microscope. Six species of small scale fresh water fish were examined namely, Puntius brevis, Cyclocheilichthys apogon Cyclocheilichthys repasson, Cyclocheilichthys armatus, Puntius orphoides and Labiobarbus lineatus. 5 species of these fish were positive for Opisthorchis viverrini infections (the exception was L. lineatus). However, they were all susceptible species to small intestinal fluke infections, and the infection rates were slightly higher than those of liver fluke infections. The highest prevalence of Opisthorchis viverrini (16.7%) was among Cyclocheilichthys apogon and the highest prevalence of small intestinal fluke infections (60%) was among Puntius brevis. This was in Ban Leam Kak, Wang Thong District, Phitsanuloke province, [ N 16 44' 0.8" E 10022' 24.0"]. The geographic information (latitude and longitude) associated with the infection rates among susceptible species of fresh water fish was recorded and used to build a geographical information system. A number of environmental parameters such as mean yearly temperature, rainfall level, land use, NDVI, and population density were imported to the system as well. The development of GIS can be useful in establishing a prevention strategy for the transmission of food borne diseases from infected fish in water catchment areas.