回溯性探討臺北市野生與遊蕩動物之救傷原因及其最終結果

Abstract

隨著都市化的速度加劇以及特殊寵物貿易的興起，人類與野生動物間的交互影響也越來越複雜且深遠，於城市中的野生動物，其生活受人為的干擾更甚。在臺灣，野生、無主或遊蕩的動物主要由政府負責照護、收容或處置。於政府的主要工作項目可分為野生動物救傷、野生動物管理、外來種移除、無主遊蕩動物救援收容照養等項目。為利進行野生動物管理，了解臺灣當前無主遊蕩動物的族群結構、野生動物面臨的威脅、野生動物的傷病原因等是相當重要的課題，本研究透過分析進入地方政府救傷體系的動物種類、動物入所原因、臨床表現及處理結果等，嘗試了解目前於臺灣都會區生存的野生動物族群結構，以及對於野生動物生存潛在的威脅；除此之外，為了解影響野生動物死亡的預後因素，於本研究中另針對野生動物進入動物保護處時所記錄的臨床表癥進行死亡與否的分析，以期找出與野生動物死亡有關的風險因子。本研究回溯性分析民國99年至民國107年（2010-2018）共計9年間，總計27,857隻進入台北市動物保護處的動物記錄，將入所動物依不同生態學、生物分類學定義，分類為野生兩棲爬蟲類動物、外來入侵種兩棲爬蟲類動物、遊蕩兩棲爬蟲類動物、野生鳥類、外來入侵種鳥類、遊蕩鳥類、野生哺乳類動物、遊蕩哺乳類動物等八大類，並依據所記載的動物種類、民眾通報動物入所理由、理學檢查結果、後續處理方式等資料，使用敘述性統計分析比較不同生態學、生物分類學定義的動物，於入所的數量、年份、季節、行政區、成幼、動物入所原因、臨床表癥、處理結果和處理時效上的差異。另針對入所原因為創傷、疾病（鳥類及哺乳類分開）或入所臨床表癥為無異狀的動物，使用邏輯式迴歸分析入所時呈現的臨床表癥中，與死亡有關的預後因子。本研究共計將264種27,676隻動物納入分析，包含鳥類149種12,495隻（45.1％）、兩棲爬蟲類86種13,737隻（49.6％）以及哺乳類動物29種1,444隻。分析發現，野生鳥類入所的數量逐年上升且超過兩棲爬蟲類動物的入所數量，而動物入所與季節有顯著的關連性，冬季入所動物的數量較春季、夏季及秋季少。動物與人類衝突事件是對於野生兩棲爬蟲類動物來說最大的威脅，也是最常見的入所原因（46.7％）。入所動物的總死亡率為14.9％，於疾病（43.70％）和創傷（23.75％）的死亡率顯著較其他不同入所原因高。另禽痘病毒感染是目前對於臺北市野生鳥類，尤其是野生鳩鴿科鳥類，最大的威脅。出現感染禽痘病毒症狀者死亡率高達92.8％；創傷動物中，最常見的創傷種類為受困於陷阱中（14.18％）。至於與動物死亡有關的風險因子，本研究發現，在入所原因為創傷的動物中，出現單一傷口（OR = 1.6, 95％ CI = 1.2-2.2）、多重傷口（OR = 1.9, 95％ CI = 1.2-2.9）、骨折（OR = 3.6, 95％ CI = 2.7-5.0）以及中樞神經症狀（OR = 22.2, 95％ CI = 2.9-170.3）或癱瘓（OR = 12.5, 95％ CI = 3.8-41.1），皆與死亡事件發生與否有高度相關，且以出現中樞神經症狀的死亡風險最高。於疾病的哺乳類動物中，入所時的精神狀態為沉鬱或昏迷（OR = 10.7, 95％ CI = 3.6-31.6）或出現與神經系統相關症狀（OR = 12.0％ CI = 2.5-56.0），皆與死亡事件發生與否有高度相關；於疾病的鳥類動物，除入所時的精神狀態（OR = 2.4, 95％ CI = 1.8-3.2）、出現與神經系統相關症狀外（OR = 15.2, 95％ CI = 8.8-26.1），出現全身循環系統性症狀（OR = 28.2, 95％ CI = 3.9-205.5）或出現禽痘病毒感染症狀（OR = 7.9, 95％ CI = 5.6-10.9），皆為與死亡事件發生與否有顯著關連，而以出現全身循環系統性症狀的死亡風險最高，至於評估無臨床症狀的動物，若入所時呈現體態較差（OR = 2.6, 95％ CI=2.1-3.1）或精神狀態為沉鬱或昏迷（OR = 17.3, 95％ CI = 14.3-20.8），則有較高的死亡風險。就我們的認知，本研究是現今臺灣最大規模、最長期、救傷動物隻數及動物種類數最多的ㄧ份救傷研究，對於後續野生動物管理、臨床醫師和第一線救援人員精進傷病野生動物的救援及照護的作業流程，應有所助益。

With the rapid urbanization and exotic pet trade, the interaction between human and wild animals becomes more complicated resulting in an increased physiological stress and anthropogenic impacts on city-dwelling wild animals. In Taiwan, wildlife management is also the government’s duty, including wildlife rescue, wildlife rehabilitation, and removal of the invasive species. In order to better manage the wildlife, understanding the composition of wildlife, the threat to wildlife, and the morbidity and mortality of diseased wildlife are relatively important. The aims of the present study were to analyze the causes of admission, clinical presentation, and outcome of the wild animals, invasive animals, and free-ranging animals admitted to the Taipei Animal Protection Office (TAPO), the government facility responsible for managing the free-ranging animals in Taipei, Taiwan, and to figure out the most important threat to the city-dwelling animals. On the other hand, the present study also tried to identify the prognostic indicators which may be associated with animal mortality during the stay in TAPO. In the study, descriptive analysis and logistic regression model were created to determine the mortality-related factors for different variables (body condition (BC), clinical signs, and mental status). A total of 27,676 admissions during the period of 2010 to 2018 of 264 animal species were included in the study, including 149 avian species (n = 12,495), 83 reptilian species (n = 13,737), 29 mammalian species (n = 1,444), and 3 amphibians (n = 31). The number of wild birds was increasing yearly. The number of animals admitted was season-related. The number of admitted animals was significantly higher in spring, summer, and fall than in winter. The most frequent cause of admissions was animal-human comflicts (46.7％), followed by picked up by citizen (15.5％) and diseased (8.9％). In the wild reptilian/amphibian groups, animal-human comflicts was the most important threat. There were 4,121 animals dying during the rehabilitation process (mortality rate = 14.9％). The highest mortality rate was observed in the ‘disease’ category (43.7％), followed by the ‘trauma’ category (23.8％). In the diseased category, avipoxvirus infection in wild birds, especially in Columbidae was the most common clinical presentation. Trap was the main cause of trauma in Taipei (14.2％). In the bivariate analysis, the presence of wound (OR = 1.6, 95％ CI = 1.2-2.2), multiple wounds (OR = 1.9, 95％ CI = 1.2-2.9), fractures (OR = 3.6, 95％ CI = 2.7-5.0), central nervous system signs (OR = 22.2, 95％ CI = 2.9-170.3), paralysis (OR = 12.5, 95％ CI = 3.8-41.1) or poor mental status (OR = 7.4, 95％ CI = 5.4-10.1) was all associated with mortality in traumatized animals. In diseased mammal group, the presence of nervous systemic signs (OR = 12.0％ CI = 2.5-56.0) or poor mental status (OR = 10.7, 95％ CI = 3.6-31.6) was associated with mortality. In diseased bird group, beside the presence of nervous systemtic signs (OR = 15.2, 95％ CI = 8.8-26.1) or poor mental status (OR = 2.4, 95％ CI = 1.8-3.2), infected by avipoxvirus(OR = 7.9, 95％ CI = 5.6-10.9) or the presence of systemic circulated signs(OR = 28.2, 95％ CI = 3.9-205.5) was also associated with mortality. In the group with no obvious clinical signs, both poor mental status (OR = 17.3, 95％ CI = 14.3-20.8) and poor BC (OR = 2.6, 95％ CI=2.1-3.1) were significant risk factors. To our knowledge, this was the first regional survey of the morbidity and mortality in city-dwelling wild animals in Taiwan. The investigation would provide useful information for detecting potential menaces to city-dwelling wild animals.