青海省藏犬和野生狐狸棘球绦虫感染调查及虫种分子鉴定

SURVEY AND MOLECULAR IDENTIFICATION OF ECHINOCOCCUS SPECIES IN TIBETAN DOGS AND WILD FOXES IN QINGHAI PROVINCE

为了解青海省藏犬和野生狐狸的棘球绦虫Echinococcus感染状况及感染种类，本研究在青海省7个地区调查了175条藏犬和28只野生狐狸，对感染藏犬和野生狐狸的21株棘球绦虫分离株，线粒体DNA（mtDNA）的COI、NDI基因种属特异性序列进行了研究。结果表明，16条藏犬感染棘球绦虫，感染率为9．14％。5只野生狐狸感染棘球绦虫，感染率17．86％。测定的棘球绦虫mtDNA的COI、NDI基因片段长度分别为285、507、510bp，通过基因序列分析，发现青海省存在3种棘球绦虫混合感染，藏犬存在Echinococcusgranulosusgenotype1（E．g1）和Echinococcusmultilocularis（E．m）感染，部分藏犬存在E．g1和E．m混合感染，野生狐狸存在E．m和Echinococcusshiquicus（E．5）感染。检测的21株棘球绦虫分离株中，E．gl11株，占52．4％，E．m6株，占28．6％，E．s4株，占19．O％。COI基因存在15个不同的基因序列，种内变异率小于2．5％，种间变异率大于8．2％。NDI基因存在17个不同的基因序列，种内变异率小于1．6％，种间变异率大于17．3％。

To understand the Echinococcus species and its infections, 28 wild foxes and 175 Tibetan dogs were surveyed in seven different regions of Qinghai Province, by using 2 mitochondrial target genes （ CO I and ND I ）. 5 strains were isolated from foxes and 16 from dogs. The results showed that the infection rate of Echinococcosis infected with wild foxes and Tibetan dogs were 17.86% and 9. 14% , respectively. The length of the fragment of CO I and ND I of Echinococcus strains was 285 and 507, 510 bp. And it appeared that three species of Echinococcus were prevalent mixedly infection in Qinghai Province. Among the three species of Echinococcus, Tibetan dogs can be infected with Echinococcus granulosus genotype 1 （E. g 1 ） or Echinococcus multilocularis （E. m）, part of the dogs can be infected mixedly by E. gl and E. m, and wild foxes were found only infected with E. m or Echinococcus shiquicus （E. s）. In 21 Echinococcus isolates, 52.4% was E. gl,28.6% was E. m, 19.0% was E.s. We finally obtained 15 different genes haploid in CO I , and the rate of intraspecific variation is less than 2. 5% , meanwhile, the interspecific variation rate is greater than 8.2%. There were 17 different genes haploid in ND I , and the rate of intraspecific variation is less thanl. 6% , and the interspecific variation rate is greater than 17.3%.