Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan; Freshwater Aquaculture Center and College of Fisheries, Central Luzon State University, Science City of Muñoz, Nueva Ecija 3120, Philippines.
Parasitol Int. 2021 Feb;80:102228. doi: 10.1016/j.parint.2020.102228. Epub 2020 Nov 2.
In this study, Anisakis nematodes isolated from toothed and baleen whales from localities around Japan were molecularly (PCR-RFLP) identified. In Wakayama, common bottlenose dolphins (Tursiops truncatus) were infected with A. simplex sensu stricto (s.s.), A. typica and A. pegreffii, while A. typica was the only species found in pantropical spotted dolphin (Stenella attenuata) and striped dolphin (S. coeruleoalba). Offshore common minke whales (Balaenoptera acutorostrata) and sei whales (B. borealis) were almost exclusively infected with A. simplex s.s.. However, in common minke whales from two Hokkaido localities, mature worms mostly consisted of A. simplex s.s. in some individuals and of A. pegreffii in others, but immature worms were mainly A. simplex s.s.. Gross and histopathological examination on gastric mucosa attached by anisakids resulted in mild and superficial reactions by the two baleen whale species in contrast to severe inflammatory reaction associated with ulcer formations by common bottlenose dolphin. Host specificity and adaptability of Anisakis spp. in these baleen and toothed whales were discussed from the points of view of adult worm size, worm population and pathological reactions by hosts. Interestingly, most of the common minke whales predominantly harboring mature A. pegreffii adults belonged to the Yellow Sea - East China Sea stock (J stock), which migrates through the Sea of Japan, whereas most of those mainly parasitized by mature A. simplex s.s. adults were from the Okhotsk Sea - West Pacific stock (O stock), mostly inhabiting the Pacific side, suggesting that these sibling species may have utility as biological tags to differentiate whale stocks. These results represent the first definitive host records for A. pegreffi in the Northwestern Pacific Ocean.
在这项研究中，从日本各地的齿鲸和须鲸中分离出的异尖线虫通过分子（PCR-RFLP）鉴定。在和歌山，宽吻海豚（Tursiops truncatus）感染了 A. simplex sensu stricto（s.s.）、A. typica 和 A. pegreffii，而 A. typica 是唯一在热带斑点海豚（Stenella attenuata）和条纹海豚（S. coeruleoalba）中发现的物种。近海的小须鲸（Balaenoptera acutorostrata）和塞鲸（B. borealis）几乎完全感染了 A. simplex s.s.。然而，在北海道的两个地点捕获的小须鲸中，成熟的异尖线虫主要由 A. simplex s.s.组成，但在一些个体中也有 A. pegreffii，而未成熟的异尖线虫主要是 A. simplex s.s.。对胃黏膜上附着的异尖线虫进行的大体和组织病理学检查表明，两种须鲸的反应轻微且浅表，而宽吻海豚则表现出严重的炎症反应，伴有溃疡形成。从成虫大小、虫群和宿主的病理反应等方面讨论了这些须鲸和齿鲸中异尖线虫的宿主特异性和适应性。有趣的是，大多数主要携带成熟 A. pegreffii 成虫的小须鲸属于黄海-东海种群（J 种群），该种群通过日本海迁徙，而大多数主要被成熟 A. simplex s.s.成虫寄生的小须鲸来自鄂霍次克海-西太平洋种群（O 种群），主要栖息在太平洋一侧，这表明这些姐妹种可能可用作区分鲸种群的生物标记。这些结果代表了西北太平洋地区首次明确的 A. pegreffi 宿主记录。
