United States Department of Agriculture, Agricultural Research Service, Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705-2350, USA.
United States Department of Agriculture, Agricultural Research Service, Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705-2350, USA.
Vet Parasitol Reg Stud Reports. 2024 Nov;56:101122. doi: 10.1016/j.vprsr.2024.101122. Epub 2024 Sep 28.
The protozoan Sarcocystis neurona can cause severe disease in horses, marine mammals, and several other animal species in North America. The Virginia opossum (Didelphis virginiana) is its definitive host, and the raccoon (Procyon lotor) has been considered its primary intermediate host in the USA. Although canids have not previously been identified as important intermediate hosts for this parasite, we here report several natural cases in the gray fox (Urocyon cinereoargenteus). We identified muscular infections in 11 (23.9 %) of 46 gray foxes from Pennsylvania, USA. In hematoxylin and eosin (HE)-stained sections of tongue and limb muscles, only 13 sarcocysts were detected in 7 of 46 foxes, in limb muscle of 4 and in tongue of 4. In HE-stained sections, the sarcocyst wall was up to 2.7 μm-thick and contained finger-like villar protrusions. In unstained muscle squashes, 44 sarcocysts were detected; they were up to 1200 μm long and 69 μm wide. From each infected fox, only one morphologic type of sarcocyst was found. By transmission electron microscopy, these sarcocysts appeared identical to those in animals experimentally infected with S. neurona. Molecularly, sarcocysts were characterized using 18S rRNA, 28S rRNA, cox1, ITS1, rpoB, RON1, RON2, RON3, GAPDH1, ROP20, ROP21, ROP39, SnSRS21 and TUBA1; results confirmed the presence of S. neurona in the gray fox. This is the first report of muscular sarcocysts in the gray fox.
原生动物 Sarcocystis neurona 可导致北美的马、海洋哺乳动物和其他几种动物物种发生严重疾病。弗吉尼亚负鼠（Didelphis virginiana）是其终末宿主，浣熊（Procyon lotor）被认为是其在美国的主要中间宿主。尽管犬科动物以前没有被确定为该寄生虫的重要中间宿主，但我们在此报告了灰狐（Urocyon cinereoargenteus）中的几个自然病例。我们在美国宾夕法尼亚州发现了 46 只灰狐中有 11 只（23.9%）肌肉感染。在舌和四肢肌肉的苏木精和伊红（HE）染色切片中，仅在 46 只狐狸中的 7 只、4 只四肢肌肉和 4 只舌中发现了 13 个包囊。在 HE 染色切片中，包囊壁最厚可达 2.7μm，包含指状的小突起。在未染色的肌肉压片中，共检测到 44 个包囊，最长可达 1200μm，最宽可达 69μm。从每只受感染的狐狸中仅发现一种形态类型的包囊。通过透射电子显微镜观察，这些包囊与用 S. neurona 实验感染的动物中的包囊相同。通过 18S rRNA、28S rRNA、cox1、ITS1、rpoB、RON1、RON2、RON3、GAPDH1、ROP20、ROP21、ROP39、SnSRS21 和 TUBA1 对包囊进行分子鉴定，结果证实了灰狐中存在 S. neurona。这是首次在灰狐中报道肌肉包囊。
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