Morell Maria, Lehnert Kristina, IJsseldijk Lonneke L, Raverty Stephen A, Wohlsein Peter, Gröne Andrea, André Michel, Siebert Ursula, Shadwick Robert E
Zoology Department, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada.
Dis Aquat Organ. 2017 Dec 19;127(1):57-63. doi: 10.3354/dao03178.
Peribullar sinuses of harbour porpoises Phocoena phocoena are parasitized with high prevalence by the nematode Stenurus minor. The effect of S. minor on the hearing ability of this species is still undetermined. Here, we review the occurrence of S. minor in the inner ear of harbour porpoises recovered from strandings in the North and Baltic Seas. In particular, we present the results from ears collected in German and Danish waters from 2002 to 2016 and from Dutch waters from 2010 to 2016. While the prevalence of S. minor in pterygoid and peribullar sinuses and tympanic cavity was high in harbour porpoises (66.67% in our cases), its prevalence in the cochlea was rare. Only 1 case out of 129 analysed by either histology, electron microscopy or immunofluorescence showed the presence of a nematode parasite morphologically consistent with S. minor at the most basal portion of the right cochlea. This individual also had severe haemorrhage along the right cochlear spiral, which was likely caused by ectopic S. minor migration. Although this animal might have had impaired hearing in the right ear, it was otherwise in good body condition with evidence of recent feeding. These findings highlight the need to study the effect of parasites on hearing, and other pathological changes that might impair appropriate processing of acoustic information.
港湾鼠海豚（Phocoena phocoena）的球周窦被线虫小窄体线虫（Stenurus minor）大量寄生。小窄体线虫对该物种听力的影响仍未确定。在此，我们回顾了在北海和波罗的海搁浅后被回收的港湾鼠海豚内耳中小窄体线虫的出现情况。特别是，我们展示了2002年至2016年在德国和丹麦水域以及2010年至2016年在荷兰水域收集的耳样本的结果。虽然港湾鼠海豚翼状窦、球周窦和鼓室中小窄体线虫的感染率很高（在我们的案例中为66.67%），但其在耳蜗中的感染率很低。在通过组织学、电子显微镜或免疫荧光分析的129个样本中，只有1例在右耳蜗最基部发现了形态上与小窄体线虫一致的线虫寄生虫。该个体右耳蜗螺旋也有严重出血，这可能是由小窄体线虫异位迁移引起的。虽然这只动物右耳听力可能受损，但它的身体状况良好，有近期进食的迹象。这些发现凸显了研究寄生虫对听力以及其他可能损害声学信息适当处理的病理变化影响的必要性。
