硬蜱的宿主動物以及和是否寄生人類的關係

Host associations of the hard tick (Ixodidae) and its affiliation with humans

林彥瑜(Lin Yen-Yu)

指導教授 ： 郭奇芊

國立臺灣師範大學/理學院/生命科學系/碩士(2020年)

https://doi.org/10.6345/NTNU202001668

摘要

硬蜱(Ixodidae)能傳播許多疾病，對人類健康有相當程度的威脅。多數種類硬蜱會經歷需要寄生於宿主身上，吸食宿主血液才能蛻化為下一個生活史階段或產卵的幼蟲、若蟲和成蟲階段，也因此適當的宿主動物，尤其是陸生脊椎動物的存在，為硬蜱族群存活不可或缺的一環。本研究參考The Hard Ticks of the World以及1,450篇相關文獻，收集了全世界705種硬蜱共6,016種硬蜱和陸生脊椎動物宿主(以科為階層)的寄生關係。結果發現多數硬蜱種類(466種)的宿主數量介於1-10科，但記錄到最多宿主的微小扇頭蜱(Rhipicephalus microplus)，宿主數量可達65科；同樣地，247科宿主中，多數宿主(158科宿主)被少於10種硬蜱寄生，但亦有16科的宿主寄生有超過100種硬蜱，其中哺乳綱動物佔了15科(包括人類自人科分出自成一類群)，鳥綱僅占1科。各個硬蜱屬亦以利用哺乳綱動物宿主的頻度最高，其次多為鳥綱，爬行綱動物宿主則被Amblyomma屬硬蜱利用最多次。會叮咬人類的硬蜱，其宿主數量顯著高於不會叮咬人類的硬蜱，且和哺乳綱動物的宿主數量最相關。最後藉由網路分析，發現人類和23科哺乳綱，10科鳥綱以及1科爬行綱動物有較多共同的寄生硬蜱種類，鳥綱中的雉科、鶇科亦與哺乳綱動物有許多相同硬蜱。本研究受限於宿主的多寡，會受到硬蜱種類被研究程度所影響，以及宿主只區分到科而非種的層級，但是本研究首次大規模收集全世界硬蜱的宿主資料，尤其得知人類和哪些動物宿主寄生有相同種類的硬蜱，能夠幫助推估人類和哪些特定動物宿主之間，較可能互相傳播蜱媒疾病。

關鍵字

硬蜱 ； 宿主 ； 脊椎動物 ； 寄生關係 ； 網路分析

並列摘要

Hard ticks (Ixodidae) can transmit many diseases to humans. The life cycle of most tick species includes larva, nymph and adult stages that require blood meals from hosts to molt or lay eggs. Therefore, suitable hosts, particularly terrestrial vertebrates, are indispensable for the survival of hard ticks. In this study, I scrutinized 1,450 scientific references in addition to the book “The Hard Ticks of the World” and recorded 6,016 unique tick-host (family level) associations of 705 species of hard ticks. I found that the number of hosts of most tick species was limited to one to 10 host families, but one species with the most hosts, Rhipicephalus microplus, can be observed on as many as 65 families. Similarly, most vertebrate hosts (158 out of a total of 247 families) were infested with fewer than 10 tick species; however, there were 16 families that hosted more than one hundred species of ticks, including 15 mammalian and one avian families (human being Homo sapiens was herein separated from other members of Hominidae). Mammals were also parasitized by different genera of ticks with the highest frequency, followed mostly by birds. Reptiles were more frequently infested with Amblyomma ticks. Tick species that infested humans parasitized more host families, especially mammalian hosts, compared to those that did not infest humans. Lastly, network analyses revealed that humans hosted the same tick species with 23 mammalian, 10 avian, and one reptilian families. Additionally, among birds, pheasants and thrushes more frequently shared tick species with mammals. In this study, the number of host families could by determined by differential sampling efforts for different tick species; besides, hosts were identified to family instead of species level. Nevertheless, this is the first study to document hosts of all hard tick species. More importantly, the information on shared tick species among humans and certain groups of vertebrates could help predict which animals might transmit tick-borne pathogens to humans.

並列關鍵字

Hard ticks ； Hosts ； Vertebrates ； Parasitism ； Network analysis

參考文獻

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