Laboratorio de Medicina Veterinaria, Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile.
Instituto de Ciencias Agroalimentarias, Animales y Ambientales (ICA3), Universidad de O'Higgins, San Fernando, Chile.
Vet Res. 2020 Jun 5;51(1):76. doi: 10.1186/s13567-020-00799-5.
Polyparasitism occurs when animals harbour multiple parasites concomitantly. It is a common occurrence but is generally understudied in wild and domestic animals. Fasciola hepatica and Echinococcus granulosus, which are helminths of ungulates, frequently coinfect cattle. The effects of this particular type of polyparasitism are not well documented. The metacestode of Echinococcus granulosus is surrounded by the adventitial layer, which constitutes the host immune response to the parasite. This layer in cattle is produced by a granulomatous reaction and is involved in echinococcal cyst (EC) fertility. Due to the systemic immune-modulating abilities of Fasciola hepatica, coinfection possibly generates a favourable environment for EC growth. A total of 203 Echinococcus granulosus sensu stricto cysts were found in 82 cattle, of which 42 ECs were found in 31 animals coinfected with Fasciola hepatica. The overall infection intensity was 3 cysts per animal. Coinfection with Fasciola hepatica decreased the mean infection intensity to 1.4 cysts per animal. Regarding EC size, coinfection resulted in smaller ECs (15.91 vs 22.09 mm), especially for infertile lung cysts. The adventitial layer of ECs in coinfected animals lacked lymphoid follicles and palisading macrophages, which are generally hallmarks of the granulomatous immune response. The ECs in coinfected animals had organized laminated layers, whereas those in animals without coinfection did not. Although coinfection was not statistically associated with EC fertility, we did not find fertile cysts in the livers of coinfected animals. We concluded that coinfection with Fasciola hepatica and Echinococcus granulosus has a detrimental effect on ECs, particularly infertile cysts.
多寄生虫感染是指动物同时携带多种寄生虫。这种情况很常见，但在野生动物和家养动物中研究得并不充分。肝片吸虫和细粒棘球蚴是偶蹄动物的寄生虫，常共同感染牛。这种特定类型的多寄生虫感染的影响尚未得到充分记录。细粒棘球蚴的囊尾蚴被囊外膜包围，这构成了宿主对寄生虫的免疫反应。牛的这种外膜是由肉芽肿反应产生的，与棘球蚴囊（EC）的生育能力有关。由于肝片吸虫具有系统性免疫调节能力，共同感染可能为 EC 的生长创造了有利环境。在 82 头牛中发现了 203 个细粒棘球蚴囊，其中 31 头同时感染肝片吸虫的牛中有 42 个 EC，总感染强度为每头牛 3 个囊。与肝片吸虫共同感染将平均感染强度降低至每头牛 1.4 个囊。关于 EC 大小，共同感染导致 EC 变小（15.91 毫米对 22.09 毫米），特别是对于不育的肺 EC。共同感染动物的 EC 囊外膜缺乏淋巴滤泡和栅栏状巨噬细胞，这些通常是肉芽肿免疫反应的标志。共同感染动物的 EC 具有有组织的层状结构，而未共同感染动物的 EC 则没有。虽然共同感染与 EC 的生育力没有统计学关联，但我们在共同感染动物的肝脏中没有发现可育的囊肿。我们得出结论，肝片吸虫和细粒棘球蚴的共同感染对 EC 有不利影响，特别是对不育的囊肿。
