Figure. Map of Laos. The area in which Schistosoma mekongi is known to be endemic is highlighted in light blue. The area highlighted in light yellow shows both the known area and the area predicted by Attwood’s paleogeographic models (1) to be inhabited by Neotricula aperta (freshwater snails), the known intermediary host for S. mekongi. Two foci of travel-related schistosomiasis are also highlighted with red stars. The dark blue line shows the route of the Mekong River.