Dubey Jitender P, Gupta Aditya, Rosenthal Benjamin M, Calero-Bernal Rafael, Humpal Carolin, Carstensen Michelle
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. 2025 Aug;63:101319. doi: 10.1016/j.vprsr.2025.101319. Epub 2025 Jul 15.
Species of Sarcocystis parasitize a wide range of vertebrate hosts, sometimes causing disease in humans and animals. Here, frozen muscles of 239 bobcats (Lynx rufus) from Minnesota were tested for Sarcocystis infections. After thawing, muscles were examined microscopically by compression preparations of unfixed muscles and histological sections of paraffin embedded tissues. Some sarcocysts were later characterized using electron microscopy and gene sequencing for comparison to other Sarcocystis species in the genus. In the first batch of 50 bobcats trapped in 2014-2015, only tongues were examined histologically and sarcocysts were found in 21 (42 %). In the second batch of 140 bobcats trapped in 2023-2024, tongues and limb muscles were examined by combined methods (histology and compression smears) detected infection in the muscles of 44 (31.4 %). In the third batch of 49 bobcats trapped in 2025, tongues, limb muscles and myocardium were examined histologically, and sarcocysts were found in histological sections of 15 tongues, 7 limb muscles and none in hearts. In two of these most heavily infected bobcats, myositis was found in limb muscles. Overall, sarcocysts were detected in 82 of 239 (34.3 %) bobcats. Based on the character of the sarcocyst walls by light microscopy, three morphologic types of sarcocysts were detected. With transmission electron microscopic examination, one of these sarcocyst types could not be distinguished from Sarcocystis felis (originally described from the bobcat) or Sarcocystis caninum (described from the domestic dog) in this study. Multilocus genotyping confirmed one of the Sarcocystis derived from bobcat tongue samples to be either Sarcocystis arctica or Sarcocystis caninum, with all three gene regions (18S rRNA, 28S rRNA, and cox1) showing 98-100 % sequence identity to isolates of S. arctica or S. caninum; S. felis has not been molecularly characterized from the bobcat. Phylogenetic analysis also revealed the clustering of specimens under study with isolates of S. arctica and S. caninum with strong bootstrap support. Results of the study affirm that contrary to assumptions, muscular Sarcocystis infections in bobcats are common, Sarcocystis species may not be host specific in the carnivorous hosts, and some of them cause clinical disease in dogs.
肉孢子虫属的物种寄生于多种脊椎动物宿主，有时会导致人类和动物患病。在此，对来自明尼苏达州的239只短尾猫（加拿大猞猁）的冷冻肌肉进行了肉孢子虫感染检测。解冻后，通过未固定肌肉的压片制备和石蜡包埋组织的组织学切片对肌肉进行显微镜检查。一些肉孢子虫后来通过电子显微镜和基因测序进行了特征分析，以便与该属中的其他肉孢子虫物种进行比较。在2014 - 2015年捕获的第一批50只短尾猫中，仅对舌头进行了组织学检查，在21只（42%）中发现了肉孢子虫。在2023 - 2024年捕获的第二批140只短尾猫中，通过联合方法（组织学和压片涂片）对舌头和肢体肌肉进行检查，在44只（31.4%）的肌肉中检测到感染。在2025年捕获的第三批49只短尾猫中，对舌头、肢体肌肉和心肌进行了组织学检查，在15只舌头的组织学切片中发现了肉孢子虫，7只肢体肌肉中发现了肉孢子虫，心脏中未发现。在其中两只感染最严重的短尾猫中，在肢体肌肉中发现了肌炎。总体而言，在239只短尾猫中的82只（34.3%）检测到了肉孢子虫。根据光学显微镜下肉孢子虫囊壁的特征，检测到三种形态类型的肉孢子虫。通过透射电子显微镜检查，在本研究中，这些肉孢子虫类型之一无法与猫肉孢子虫（最初从短尾猫中描述）或犬肉孢子虫（从家犬中描述）区分开来。多位点基因分型证实，来自短尾猫舌头样本的一种肉孢子虫为北极肉孢子虫或犬肉孢子虫，所有三个基因区域（18S rRNA、28S rRNA和cox1）与北极肉孢子虫或犬肉孢子虫分离株的序列同一性为98 - 100%；尚未从短尾猫中对猫肉孢子虫进行分子特征分析。系统发育分析还显示，所研究的标本与北极肉孢子虫和犬肉孢子虫分离株聚类，具有很强的自展支持。该研究结果证实，与假设相反，短尾猫的肌肉肉孢子虫感染很常见，肉孢子虫物种在食肉宿主中可能不是宿主特异性的，并且其中一些会在犬类中引起临床疾病。
