Nagao Y, Svasti P, Tawatsin A, Thavara U
Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Epidemiol Infect. 2008 Jun;136(6):843-51. doi: 10.1017/S0950268807008990. Epub 2007 Jul 12.
Expansion of dengue has been attributed to urbanization. To test this concept, we examined dengue transmission intensities in Thailand. We used the inverse of mean age of dengue haemorrhagic fever (DHF) cases as a surrogate of dengue transmission intensity (or force of infection). The transmission intensity in Bangkok decreased rapidly since the mid-1990s, to levels that are currently lower than in other regions. Regression analysis revealed that transmission intensity is highest in the Northeastern rural region, mainly due to scarcity of private water wells. Private wells reduce the need for household water containers, the major breeding sites for vectors. Cumulatively, these results show that urbanization is not necessarily associated with intense dengue transmission in Thailand. Paradoxically, the DHF incidence in Bangkok has surpassed other regions despite declines in transmission intensity. This finding implies the existence of endemic stability (i.e. low incidence of a clinical illness in spite of high transmission intensity).
登革热的传播范围扩大被认为与城市化有关。为了验证这一概念，我们研究了泰国的登革热传播强度。我们将登革出血热（DHF）病例的平均年龄倒数作为登革热传播强度（或感染力）的替代指标。自20世纪90年代中期以来，曼谷的传播强度迅速下降，目前已低于其他地区。回归分析显示，东北部农村地区的传播强度最高，主要原因是私人水井稀缺。私人水井减少了家庭储水容器的需求，而家庭储水容器是病媒的主要滋生地。总体而言，这些结果表明，在泰国，城市化不一定与强烈的登革热传播相关。矛盾的是，尽管传播强度有所下降，但曼谷的登革出血热发病率却超过了其他地区。这一发现意味着存在地方病稳定性（即尽管传播强度高，但临床疾病发病率低）。
