Dame J B, Murrell K D, Worley D E, Schad G A
Animal Parasitology Institute, U.S. Department of Agriculture, Beltsville, Maryland 20705.
Exp Parasitol. 1987 Oct;64(2):195-203. doi: 10.1016/0014-4894(87)90143-3.
Isolates of the nematode genus Trichinella from sylvatic hosts differ in their potential to reproduce in domestic swine. The structure of the genomic DNA from 13 sylvatic isolates from North America and 5 pig isolates, 4 from North America and 1 from Asia, was examined and correlated with the infectivity of the isolate for domestic pigs. DNA restriction fragment length differences, identified by ethidium bromide staining and by hybridization with 32P-labeled ribosomal RNA, served as molecular markers to classify each isolate. All 5 pig isolates and 8 of 13 sylvatic isolates had a high infectivity and reproductive capacity in pigs. All isolates that were highly infectious for pigs regardless of host origin had similar DNA characteristics and were classified operationally as T. spiralis spiralis (pig) and those of the second group as T. spiralis ssp. A DNA clone of repetitive DNA from T. s. spiralis, pBP2, was selected from a library of genomic DNA in plasmid pUC8. When used as a probe, pBP2 hybridized only to the DNA of T. s. spiralis isolates, thus making it a useful diagnostic reagent to predict whether new isolates are highly infectious for pigs (i.e., T. s. spiralis). These results show that T. s. spiralis occurs in wild mammals and this should be considered a serious obstacle to efforts to eradicate trichinellosis from domestic swine.
来自野生宿主的旋毛虫属线虫分离株在其在家猪体内繁殖的潜力方面存在差异。对来自北美的13株野生分离株以及5株猪分离株（4株来自北美，1株来自亚洲）的基因组DNA结构进行了检测，并将其与分离株对家猪的感染性进行关联分析。通过溴化乙锭染色以及与32P标记的核糖体RNA杂交鉴定出的DNA限制性片段长度差异，作为分子标记对每个分离株进行分类。所有5株猪分离株以及13株野生分离株中的8株在家猪中具有高感染性和繁殖能力。所有对猪具有高感染性的分离株，无论宿主来源如何，都具有相似的DNA特征，在操作上被分类为旋毛形线虫（猪型），第二组则分类为旋毛形线虫种。从质粒pUC8中的基因组DNA文库中筛选出了来自旋毛形线虫种的重复DNA的DNA克隆pBP2。当用作探针时，pBP2仅与旋毛形线虫种分离株的DNA杂交，因此它成为一种有用的诊断试剂，可用于预测新的分离株对猪是否具有高感染性（即旋毛形线虫种）。这些结果表明，旋毛形线虫种存在于野生哺乳动物中，这应被视为在家猪中根除旋毛虫病努力的一个严重障碍。
