Casalins Laura, Ibáñez Molina Mora, Wainer Gullo Mariana, Brugni Norma, Ortiz Gala, Ojeda Valeria
INIBIOMA (CONICET-Universidad Nac. del Comahue), Departamento de Zoología-CRUB, 8400, Bariloche, Argentina.
INIBIOMA (CONICET-Universidad Nac. del Comahue), Laboratorio de Histología Animal y Vegetal, 8400, Bariloche, Argentina.
Int J Parasitol Parasites Wildl. 2018 Dec 24;8:106-110. doi: 10.1016/j.ijppaw.2018.12.005. eCollection 2019 Apr.
We describe pathological aspects of an infection caused by parasitic nematodes in skeletal muscles of a Magellanic woodpecker (), providing the first description of any disease findings in this species. A weakened female with locomotory dysfunction was rescued near Bariloche city (Argentine Patagonia), which soon died. At the necropsy, unexpected masses of tissue were located at three joints (legs and tail). A dissection of these masses exposed numerous nematodes in the musculature surrounding the joints that were identified as (Nematoda: Diplotriaenidae), a species that was not previously found in Piciformes (woodpeckers, toucans, and allies) of the Neotropical Region. In this report, we complement the original parasite description from 1952 with SEM images, and extend the species range about 2000 km southwards. Histopathological analysis (tissues sectioned 4-6 microns, stained with hematoxylin and eosin) of the affected tissues revealed parasitic myositis with muscle fibrosis. Severe muscle degeneration and necrosis, fibrous tissue replacing muscle tissue, chronic inflammation with widespread diffuse mononuclear infiltration, and parasitic content (adult roundworms, eggs, and eggs with first-stage larvae) were present in all samples. The multifocal nature of these lesions was consistent with the locomotory dysfunction exhibited by the bird. Both the immune response (mononuclear infiltration without eosinophils, which normally fight helminth colonization) and the clinical severity of this case (a lethal, multifocal macroparasite infection) are noteworthy. The expected immune response may have been suppressed through immunomodulation by the parasite, as observed for filarial parasites. Based on their demography and life history traits (i.e., long-lived picids that produce a single nestling every 1-2 years, and live in sparse populations), Magellanic Woodpeckers do not seem to be obvious hosts of an obligately killing parasite, and other (more regular) hosts should be expected to occur in the same region.
我们描述了麦哲伦啄木鸟（）骨骼肌中由寄生线虫引起的感染的病理学特征，这是对该物种任何疾病发现的首次描述。一只行动功能障碍的虚弱雌性啄木鸟在巴里洛切市（阿根廷巴塔哥尼亚）附近被救助，它很快就死亡了。尸检时，在三个关节（腿部和尾部）发现了意外的组织肿块。对这些肿块进行解剖后，在关节周围的肌肉组织中发现了大量线虫，经鉴定为（线虫纲：双盘尾科），该物种此前未在新热带地区的雀形目（啄木鸟、巨嘴鸟及其近缘物种）中发现过。在本报告中，我们用扫描电子显微镜图像补充了1952年对该寄生虫的原始描述，并将该物种的分布范围向南扩展了约2000公里。对受影响组织进行的组织病理学分析（组织切片厚度为4 - 6微米，用苏木精和伊红染色）显示为寄生虫性肌炎伴肌肉纤维化。所有样本中均出现严重的肌肉变性和坏死、纤维组织取代肌肉组织、伴有广泛弥漫性单核细胞浸润的慢性炎症以及寄生虫成分（成虫蛔虫、虫卵和带有一期幼虫的虫卵）。这些病变的多灶性与该鸟类表现出的行动功能障碍一致。这种情况的免疫反应（无嗜酸性粒细胞的单核细胞浸润，嗜酸性粒细胞通常对抗蠕虫定植）和临床严重程度（致命的、多灶性大寄生虫感染）都值得关注。正如在丝虫寄生虫中观察到的那样，预期的免疫反应可能已被寄生虫通过免疫调节抑制。基于麦哲伦啄木鸟的种群统计学和生活史特征（即寿命长的啄木鸟科鸟类，每1 - 2年产一窝雏鸟，且生活在稀疏种群中），它们似乎并非专性致死寄生虫的明显宿主，预计在同一地区会出现其他（更常见的）宿主。
