Fukuhara Kazuma, Phompida Samlane, Insisiengmay Sithat, Kirinoki Masashi, Chigusa Yuichi, Nakamura Satoshi, Matsuda Hajime, Ishikawa Hirofumi
Department Human Ecology, Graduate School of Environmental Science, Okayama University, Okayama, Japan.
Parasitol Int. 2011 Dec;60(4):452-9. doi: 10.1016/j.parint.2011.07.017. Epub 2011 Jul 28.
Schistosomiasis mekongi is prevalent in the Khong district of Lao PDR, made up of one big island, Khong, and numerous small islands in the Mekong River. Schistosoma mekongi is spread by Neotricula aperta as the intermediate host along the Mekong River. Therefore, even if an epidemic of S. mekongi were stamped out in a certain village, infection may recur if the source of infection is a village located in the upper reaches of the Mekong River. The purpose of this study was to construct a mathematical model for the transmission of S. mekongi among villages from the upper to lower Mekong River to estimate the effect of control measures against it. The chief characteristic of the present model is competence in dealing with the spread of infection among villages through the Mekong River in consideration of the reduction in longevity of cercariae and miracidia and their diffusion in the river. The model also takes into account seasonal fluctuation in the water level of the Mekong River, which affects human behavior in terms of water contact. The results of simulations indicated that the prevalence of schistosomiasis mekongi would be suppressed to a low level for a long time in a village further downstream when universal mass treatment is performed in villages further upstream simultaneously.
湄公血吸虫病在老挝人民民主共和国孔县流行，该县由湄公河上的一个大岛——孔岛以及众多小岛组成。湄公血吸虫通过孔穴新小口螺作为中间宿主在湄公河沿岸传播。因此，即使在某个村庄消灭了湄公血吸虫病的疫情，但如果感染源是位于湄公河上游的村庄，感染可能会再次发生。本研究的目的是构建一个湄公血吸虫在湄公河上下游村庄间传播的数学模型，以评估针对该病的控制措施的效果。当前模型的主要特点是能够考虑到尾蚴和毛蚴寿命的缩短及其在河流中的扩散，从而处理感染在村庄间通过湄公河传播的情况。该模型还考虑了湄公河水位的季节性波动，这在水接触方面会影响人类行为。模拟结果表明，当在上游村庄同时进行普遍群体治疗时，下游更远的村庄中湄公血吸虫病的流行率将在很长一段时间内被抑制在较低水平。
