Scioscia Nathalia P, Olmos Leandro, Gorosábel Antonella, Bernad Lucía, Pedrana Julieta, Hecker Yanina P, Gual Ignacio, Laura Gos M, Denegri Guillermo M, Moore Dadín P, Moré Gastón
Instituto de Investigaciones en Producción, Sanidad y Ambiente (IIPROSAM), Facultad de Ciencias Exactas y Naturales, UNMdP, Funes 3350, Mar del Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
Grupo Sanidad Animal, INTA, Ruta 226 km 73.5, Balcarce, Argentina.
Parasitol Int. 2017 Jun;66(3):214-218. doi: 10.1016/j.parint.2017.01.021. Epub 2017 Feb 3.
Several Sarcocystis spp. have carnivores as definitive host and sarcocysts are common in muscles of herbivores (intermediate host). However, sarcocysts have been found in muscles of wild and domestic carnivores suggesting they are intermediate host for some Sarcocystis spp. Here, we report mature sarcocysts in the muscles of Pampas fox (Lycalopex gymnocercus). A total of 36 free-living foxes were analyzed. Different skeletal muscles were assessed by microscopic and molecular methods. Cysts and/or DNA of Sarcocystis sp. were detected in 61.1% (22/36) foxes. Histopathology revealed the presence of sarcocysts in 52.8% (19/36) foxes. The tongue and masseter were the muscles more frequently infected. Of all the samples processed by homogenization of pooled muscles of each animal, 45.4% (10/22) evidenced muscle cysts and 68.2% (15/22) resulted positives by PCR. Individual cysts obtained from the ten positive samples in direct microscopic examination were all positive by PCR. Five amplicons from individual cysts from different samples were selected for sequencing together with four PCR products obtained from the pooled muscles. All nine sequences shared a high identity among them (99.8-100%) and showed the highest identity by BLAST (99%) with a S. svanai sequence (KM362428) from a North American dog. By transmission electron microscopy, the sarcocyst wall was thin (<1μm), had minute undulations, with tiny evaginations and without evident villar protrusions. The cyst wall type is referred as "type 1". Sarcocystis svanai infects L. gymnocercus with a high prevalence and the presence of mature sarcocysts suggests the role of the Pampas fox as natural intermediate host. The definitive host of S. svanai remains unknown.
几种肉孢子虫以肉食动物作为终末宿主，而肉孢子囊在草食动物（中间宿主）的肌肉中很常见。然而，在野生和家养肉食动物的肌肉中也发现了肉孢子囊，这表明它们是某些肉孢子虫的中间宿主。在此，我们报告在潘帕斯狐（草原狐，Lycalopex gymnocercus）的肌肉中发现了成熟的肉孢子囊。总共对36只野生狐进行了分析。通过显微镜和分子方法评估了不同的骨骼肌。在61.1%（22/36）的狐狸中检测到了肉孢子虫属的囊肿和/或DNA。组织病理学显示52.8%（19/36）的狐狸存在肉孢子囊。舌头和咬肌是感染频率更高的肌肉。在对每只动物的合并肌肉进行匀浆处理的所有样本中，45.4%（10/22）有肌肉囊肿，68.2%（15/22）通过PCR检测呈阳性。在直接显微镜检查中从十个阳性样本中获得的单个囊肿通过PCR检测均为阳性。从不同样本的单个囊肿中选取了五个扩增子进行测序，并与从合并肌肉中获得的四个PCR产物一起测序。所有九个序列之间具有高度同一性（99.8 - 100%），通过BLAST与来自一只北美狗的斯氏肉孢子虫序列（KM362428）显示出最高同一性（99%）。通过透射电子显微镜观察，肉孢子囊壁薄（<1μm），有微小起伏，有微小的外翻，且无明显的绒毛状突起。囊肿壁类型被称为“1型”。斯氏肉孢子虫以高流行率感染草原狐，成熟肉孢子囊的存在表明潘帕斯狐作为天然中间宿主的作用。斯氏肉孢子虫的终末宿主仍然未知。
