2013-2018年臺灣鼬獾(Melogale moschata subaurantiaca)狂犬病疫情的時空變遷趨勢與地景特徵探討

Abstract

臺灣於1961年後未有狂犬病之死亡案例，曾正式宣告撲滅狂犬病。然而於2013年7月，首次發現臺灣鼬獾(Melogale moschata subaurantiaca)確診為狂犬病案例；同月23日，發生狂犬病鼬獾咬人之案件。而根據病毒之親緣關係顯示，鼬獾狂犬病受到數個地理障礙隔離，分別為大安溪、濁水溪、高屏溪以及中央山脈。由於臺灣鼬獾狂犬病的疫情之時空分布皆尚未有完整的研究，為呈現其2013-2018年間之趨勢變化，本研究由行政院農委會動植物防疫檢疫局發布之被動監測資料取得鼬獾狂犬病之死亡案例，並從新聞媒體報導追溯狂犬病鼬獾咬人案例，以地理資訊系統呈現鼬獾狂犬病死亡案例與咬傷人報導案例之時空變化趨勢。 結果發現死亡案例的總數量由2013年的最高峰(253例)逐年下降，至2016年達到最低點(43例)，於2018年重新上揚至110例。在研究期間共出現三個顯著的空間聚集群(p ≦ .001)，死亡案例之主要分布區域由臺東縣成功鎮逐年北移至花蓮縣光復鄉，兩鄉鎮中心點距離約為43公里，並已於2018年跨越秀姑巒溪；而中部地區的大安溪仍為重要的地理屏障。在季節動態方面，鼬獾狂犬病之死亡案例主要發生於1月，咬傷人報導案例高峰期則為2月及7月，推測兩者分別與亞成體播遷以及鼬獾繁殖季有關。此外，本研究整合環境因子資料製作鼬獾之物種分布預測模式，結果顯示鼬獾在山地以及森林環境的出現機率較高；另將模式預測之鼬獾分布網格與狂犬病分布網格進行比較，狂犬病分布網格之平均海拔高度明顯較鼬獾分布網格低(p < .001)；主成分分析則顯示，狂犬病分布網格主要與人為活動之環境因子有關。相較於鼬獾之分布，狂犬病案例主要位於較低海拔與人類活動區周圍。

Taiwan had not found any rabies death case after 1961, and it was declared to be rabies-free. However, a first case of Taiwan ferret badger (Melogale moschata subaurantiaca) diagnosed as rabid case in July 2013, and also a rabid ferret badger biting case occurred on 23rd of the same month. According to previous research, the phylogenetic relationship showed rabies virus in Taiwan ferret badger was isolated by several geographical barriers, which including Da’an River, Zhuoshui River, Gaoping River and Central Mountain Range. Until now, epidemiology cycle and spatial distribution of rabies in Taiwan ferret badger have not been fully studied. Therefore, this study is intended to present the epidemiology trend during 2013-2018. We obtained the passive monitoring data of death case in rabid Taiwan ferret badger released by Bureau of Animal and Plant Health Inspection and Quarantine Council of Agriculture, Executive Yuan, and also retrieved reported rabid Taiwan ferret badger biting cases from published news. We presented the trend of temporal-spatial feature in rabid death cases and biting cases by GIS. Result shows the number of rabid death cases declined from the highest peak (253 cases) in 2013, reached a lowest number (43 cases) in 2016, and then re-raised to 110 cases in 2018. There were three significant spatial clusters during the study period (p ≦ .001), and the primary distribution area of rabid death cases was moving northward from the Chenggong Township in Taitung County to Guanfu Township in Hualian County. The center distance of these two townships is about 43 kilometers. The rabid areas have crossed Xiuguluan River in 2018, while Da’an River still acts as an important geographical barrier in central area of Taiwan. On the aspect of seasonal dynamics, rabid death cases mainly occurred in January; peak of rabid biting cases arose in February and July. These peak periods of rabid cases may be related to juvenile migration and breading season of ferret badger. Furthermore, this study integrated environmental factors to build a species distribution model of ferret badger. The model indicates ferret badgers prefer mountainous and forest area. Compare to distribution of ferret badger, distribution of rabid cases has lower average elevation significantly (p < .001). According to principle component analysis, distribution of rabid cases is linked to environmental factors for human activities. It is concluded that rabid cases tended to locate in lower elevation and near the human activity area.