寄生于猫的马来西亚弓首蛔虫在我国的发现

目的对采集于广州1只猫小肠内、形态与犬弓首蛔虫相似的寄生虫进行分子生物学鉴定。方法以核糖体DNA(rDNA)内转录间隔区(ITS)作为遗传标记对虫体进行种特异PCR鉴定,并测定了ITS-2序列,将序列与犬弓首蛔虫、猫弓首蛔虫、马来西亚弓首蛔虫序列进行比较,得到其序列的相似性和差异性。结果用马来西亚弓首蛔虫种特异性引物对试验虫体DNA进行扩增时,能扩增出明显的DNA片段,而犬弓首蛔虫、猫弓首蛔虫种特异性引物对试验虫体DNA扩增时不能扩增出任何DNA片段。试验虫体的ITS-2序列与马来西亚弓首蛔虫的ITS2序列相似性为100%,与猫弓首蛔虫的相似性为88.7%～89.0%,与犬弓首蛔虫相似性为75.8%。结论经分子生物学和形态学鉴定,从广州猫体采集的蛔虫为马来西亚弓首蛔虫,在我国为首次发现。

First documentation of Toxocara malaysiensis in cat from Chinese Mainland

The objective of the present study was to identify two individuals of an ascaridoid collected from the intestine of a cat from Guangzhou, China, by using PCR-based approaches with the internal transcribed spacers (ITS) of ribosomal DNA (rDNA) as genetic markers. With species-specific primer sets, partial ITS of rDNA was respectively amplified by PCR from the genomic DNA of two samples and were sequenced. The results showed that, while no DNA fragments were amplified from the two samples using primers specific to Toxocara canis and T. cati, a DNA fragment of expected size was amplified by PCR using primers specific to T. malaysiensis. Sequence similarity by in the ITS-2 between the two samples and T. malaysiensis, T. cati, and T. canis were 100%, 87.4%-87.7%, 75.8%, respectively. It is concluded that the two ascaridoid samples represent T. malaysiensis, which was found in cat in China for the first time.