Eckert Johannes, Ossent Pete
Institute of Parasitology, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 266a, 8057 Zurich, Switzerland.
Vet Parasitol. 2006 Jun 30;139(1-3):256-61. doi: 10.1016/j.vetpar.2006.02.042. Epub 2006 Apr 17.
A 14-year-old horse (imported to Switzerland from Ireland 8 years earlier) showed signs of chewing muscle atrophy. A severe chronic myositis, caused by numerous immature and mature female nematodes, was diagnosed in muscle samples obtained by biopsy and subsequently at necropsy. Most of the nematodes had invaded muscle fibres of the masseter, root of the tongue and anterior breast, only a few were found in the intermuscular interstitium. Isolated nematodes and parasite sections were clearly different from muscle larvae of Trichinella spp. but showed morphological similarities to Haycocknema perplexum, a nematode species (order Enoplida, family Robertdollfusidae) recently found in the musculature of a human patient in Australia. However, our material did not allow the precise identification of the nematode genus nor the unequivocal differentiation from Halicephalobus gingivalis. This species infects horses and humans and can cause severe granuloma formation in muscles and many other organ systems, but has never been observed to invade individual muscle fibres. Our findings show that nematodes of another genus than Trichinella may invade muscle fibres of the horse and cause myositis. These nematodes are provisionally regarded as Haycocknema-like.
一匹14岁的马（8年前从爱尔兰进口到瑞士）出现了咀嚼肌萎缩的症状。通过活检获取的肌肉样本以及随后的尸检诊断出，由大量未成熟和成熟的雌性线虫引起了严重的慢性肌炎。大多数线虫侵入了咬肌、舌根和前胸的肌纤维，仅在肌间组织中发现少数。分离出的线虫和寄生虫切片明显不同于旋毛虫属的肌幼虫，但在形态上与Haycocknema perplexum相似，Haycocknema perplexum是一种线虫物种（线虫纲，Robertdollfusidae科），最近在澳大利亚一名人类患者的肌肉组织中被发现。然而，我们的材料无法精确鉴定线虫属，也无法与牙龈哈氏线虫进行明确区分。该物种感染马和人类，可在肌肉和许多其他器官系统中引起严重的肉芽肿形成，但从未观察到其侵入单个肌纤维。我们的研究结果表明，旋毛虫属以外的其他属线虫可能侵入马的肌纤维并引起肌炎。这些线虫暂被视为类Haycocknema线虫。
