Hsieh Ying-Hen
Department of Public Health and Center for Infectious Disease Education and Research, China Medical University, Taichung, Taiwan.
PLoS One. 2017 May 17;12(5):e0177422. doi: 10.1371/journal.pone.0177422. eCollection 2017.
Infectious disease outbreaks often occur in the aftermath of catastrophic events, either natural or man-made. While natural disasters such as typhoons/hurricanes, flooding and earthquakes have been known to increase the risk of infectious disease outbreak, the impact of anthropogenic disasters is less well-understood. Kaohsiung City is located in southern Taiwan, where most dengue outbreaks had occurred in the past two decades. It is also the center of petrochemical industry in Taiwan with pipelines running underneath city streets. Multiple underground gas explosions occurred in Kaohsiung in the evening of July 31, 2014 due to chemical leaks in the pipelines. The explosions caused 32 deaths, including five firefighters and two volunteer firefighters, and injured 321 persons. Historically, dengue outbreaks in southern Taiwan occurred mostly in small numbers of around 2000 cases or less, except in 2002 with over 5000 cases. However, in the months after the gas explosions, the city reported 14528 lab-confirmed dengue cases from August to December. To investigate the possible impact, if any, of the gas explosions on this record-breaking dengue outbreak, a simple mathematical model, the Richards model, is utilized to study the temporal patterns of the spread of dengue in the districts of Kaohsiung in the proximity of the explosion sites and to pinpoint the waves of infections that had occurred in each district in the aftermath of the gas explosions. The reproduction number of each wave in each district is also computed. In the aftermath of the gas explosions, early waves occurred 4-5 days (which coincides with the minimum of human intrinsic incubation period for dengue) later in districts with multiple waves. The gas explosions likely impacted the timing of the waves, but their impact on the magnitude of the 2014 outbreak remains unclear. The modeling suggests the need for public health surveillance and preparedness in the aftermath of future disasters.
传染病暴发常常发生在灾难性事件之后，这些事件既可以是自然的，也可以是人为的。虽然诸如台风/飓风、洪水和地震等自然灾害已知会增加传染病暴发的风险，但人为灾害的影响却鲜为人知。高雄市位于台湾南部，在过去二十年里，这里发生了大多数登革热疫情。它也是台湾石化工业的中心，城市街道下方铺设着管道。2014年7月31日晚，高雄市因管道化学物质泄漏发生多起地下气体爆炸。爆炸造成32人死亡，其中包括5名消防员和2名志愿消防员，另有321人受伤。从历史上看，台湾南部的登革热疫情大多发生在约2000例或更少的小规模病例中，2002年除外，当时病例超过5000例。然而，在气体爆炸后的几个月里，该市报告了从8月到12月的14528例实验室确诊登革热病例。为了调查气体爆炸对这次破纪录的登革热疫情可能产生的影响（如果有的话），我们利用一个简单的数学模型——理查兹模型，来研究高雄市爆炸地点附近各区登革热传播的时间模式，并确定气体爆炸后每个区发生的感染波。还计算了每个区每一波的繁殖数。在气体爆炸后，多波感染的区中，早期波在4 - 5天后出现（这与登革热人类固有潜伏期的最小值一致）。气体爆炸可能影响了波的时间，但它们对2014年疫情规模的影响仍不清楚。该模型表明，在未来灾害之后需要进行公共卫生监测和准备工作。
