Singhanetra-Renard A
Department of Geography, Chiang Mai University, Thailand.
Soc Sci Med. 1993 Nov;37(9):1147-54. doi: 10.1016/0277-9536(93)90254-2.
This paper examines the relationship between malaria transmission and migration in three northern Thai villages. Data and observations indicate that land-poor families forced into swidden farming have greater contact with the primary vectors in Thailand--which breed in small pools in forested areas and shady clearings on hilly scrub terrain. Once infected, migrants from an endemic locus can introduce the parasite into an area with no transmission but potent vectors, thus becoming the cause of explosive epidemics; equally, non-immunes carrying out agricultural activities in or across forest and border areas can themselves be subject to seasonal morbidity. In addition to agricultural activities on clearings near forested areas, clandestine forest activities and cross border traffic contributes to the high prevalence of malaria in Thai border villages. Illegal economic activities--logging, poaching, cattle and goods smuggling--interferes with vector suppression campaigns and prompt detection of infected cases, and ultimately increases human infection not only within the mobile population, but also within the passive population of villages to which the migrants return periodically. Control measures therefore need to take into account the economic pressures which determine a high degree of mobility, the ethnic diversity of the groups which depend on fringe activities for their economic welfare, and the difficult geography of the areas in which they live. As long as economic circumstances forcing human-vector contact receives inadequate attention, better alternatives to current vector control campaigns (which are not effective amongst migrants) are not tried and malaria transmission continues.
本文研究了泰国北部三个村庄疟疾传播与人口迁移之间的关系。数据和观察结果表明，被迫从事轮垦农业的土地贫瘠家庭与泰国的主要病媒有更多接触，这些病媒在林区的小水洼以及丘陵灌丛地带的阴凉空地繁殖。一旦感染，来自疟疾流行地区的移民会将寄生虫引入一个原本没有疟疾传播但有高效病媒的地区，从而引发大规模疫情；同样，在森林或边境地区从事农业活动的非免疫人群自身也可能会季节性发病。除了在林区附近空地进行的农业活动外，秘密的森林活动和跨境交通也导致了泰国边境村庄疟疾的高流行率。非法经济活动，如伐木、偷猎、牲畜和货物走私，干扰了病媒控制行动以及对感染病例的及时发现，最终不仅增加了流动人口中的感染人数，也增加了移民定期返回的村庄中常住人口的感染人数。因此，控制措施需要考虑到导致高度流动性的经济压力、依靠边缘活动维持经济生计的群体的种族多样性，以及他们所居住地区复杂的地理环境。只要迫使人类与病媒接触的经济状况得不到充分关注，不尝试采用比当前病媒控制行动（在移民中无效）更好的替代方法，疟疾传播就会持续。
