Animal Disease Diagnostic Laboratory and Department of Comparative Pathobiology, Purdue University, 406 South University Street, West Lafayette, IN 47907, USA.
Vet Pathol. 2010 May;47(3):560-4. doi: 10.1177/0300985810363720. Epub 2010 Apr 7.
A striped skunk with neurological signs was euthanized and examined via necropsy. Histologically, protozoa were found in multiple tissues. Protozoal schizonts measured 15 to 25 mum in diameter and contained 4 to 6 mum crescent-shaped merozoites. Protozoa were associated with necrosis and inflammation in the lung, brain, liver, and nasal epithelium. Immunohistochemistry labeled protozoa strongly positive for Sarcocystis neurona. Polymerase chain reaction-amplified products from the protozoan were 99.6% identical to the corresponding portion of the nuclear small subunit ribosomal RNA gene of S neurona. S neurona origin was further confirmed by amplifying a 451-base pair DNA fragment from the skunk lung, which differed by just 2 or 3 base pairs from the small subunit ribosomal RNA gene of S neurona. Striped skunks act as intermediate and aberrant hosts for S neurona; however, S neurona has rarely been found in extraneural tissues in any species, and systemic sarcocystosis has not been reported in skunks. Additionally, canine distemper virus infection was confirmed with histopathology and immunohistochemistry. Concurrent canine distemper suggests that immunosuppression may have played a role in S neurona infection in this skunk.
一只出现神经症状的条纹臭鼬被实施安乐死并进行剖检检查。组织学检查发现，多种组织中存在原生动物。原虫裂殖体直径为 15 至 25 微米，包含 4 至 6 微米的新月形裂殖子。原生动物与肺、脑、肝和鼻上皮的坏死和炎症有关。免疫组织化学染色显示原生动物对 Sarcocystis neurona 呈强阳性反应。从原生动物中扩增的聚合酶链反应产物与 S neurona 的核小亚基核糖体 RNA 基因的相应部分完全相同，同源性为 99.6%。从臭鼬肺中扩增的 451 碱基对 DNA 片段进一步证实了 S neurona 的起源，该片段与 S neurona 的小亚基核糖体 RNA 基因仅相差 2 或 3 个碱基对。条纹臭鼬是 S neurona 的中间宿主和异常宿主；然而，在任何物种的神经外组织中很少发现 S neurona，在臭鼬中也没有报道过系统性肉孢子虫病。此外，通过组织病理学和免疫组织化学检查证实存在犬瘟热病毒感染。同时发生的犬瘟热表明，免疫抑制可能在这只臭鼬的 S neurona 感染中发挥了作用。
