Research and Diagnostic Center, Centers for Disease Control, Department of Health, Taipei, Taiwan, ROC.
Acta Trop. 2011 Oct-Nov;120(1-2):52-8. doi: 10.1016/j.actatropica.2011.05.018. Epub 2011 Jun 14.
We analyzed the spatial distribution of human cases of scrub typhus on the main island of Taiwan from 2003 to 2008 and implemented an island-wide survey of scrub typhus vectors (trombiculid chiggers) in 2007 and 2008. The standardized incidence rate 'SIR' incorporating inter-district variations in population, gender and age was correlated with environmental and socioeconomic variables. Higher incidence and SIR rates were clustered in the less developed, mountainous regions of central and eastern Taiwan. Higher SIRs were also associated with a higher proportion of dry-field farmers in the population, a higher normalized difference vegetation index (NDVI) and lower mean annual temperature, but was not associated with rainfall. Small mammal hosts in high-SIR districts harbored more chiggers and had higher rates of seropositivity against Orientia tsutsugamushi Hyashi, the etiologic agent of scrub typhus, compared to low-SIR districts. The concurrence of a higher proportion of dry-field farmers and higher NDVI has likely led to the clustering of scrub typhus in the mountainous regions of Taiwan. Further individual-level study of the risk factors associated with scrub typhus, and a better understanding of the effect of environmental factors on chigger abundance, should help to prevent scrub typhus in Taiwan.
我们分析了 2003 年至 2008 年台湾主岛恙虫病人间病例的空间分布，并于 2007 年和 2008 年对恙虫病媒介（恙螨）进行了全岛调查。结合人口、性别和年龄的地区差异，将标准化发病率（SIR）纳入分析，与环境和社会经济变量相关联。发病率和 SIR 较高的地区集中在台湾中东部欠发达的山区。较高的 SIR 还与人群中旱地农民比例较高、归一化植被指数（NDVI）较高和年平均温度较低相关，但与降雨量无关。高 SIR 地区的小型哺乳动物宿主携带的恙螨数量更多，对恙虫病病原体恙虫东方体的血清阳性率也更高，与低 SIR 地区相比。旱地农民比例较高和 NDVI 较高的情况同时出现，可能导致了台湾山区恙虫病的聚集。进一步研究与恙虫病相关的个体风险因素，并更好地了解环境因素对恙螨数量的影响，有助于预防台湾的恙虫病。
