Halajian A, Eslami A, Salehi N, Ashrafi-Helan J, Sato H
Department of Parasitology, Faculty of Veterinary Medicine, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran.
Iran J Parasitol. 2010 Jun;5(2):10-8.
The gullet worm, Gongylonema pulchrum Molin, 1857, is a thread-like spirurid nematode found in a variety of mammals worldwide. Its incidences in Iranian cattle of different breed or age have not been reported. The aims of the present study are to disclose the infection status of G. pulchrum in cattle slaughtered in northern region of Iran.
Full-length esophagi of cattle of 97 native dairy breed and 41 Holstein-Friesian breed were collected at four local abattoirs in Mazandaran Province, northern Iran, from March 2006 to August 2007, and were examined parasitologically. Eight overlapping segments of the small- and large-subunits of rDNA were amplified by PCR, and the obtained nucleotide sequences were characterized.
The incidences of G. pulchrum in female and male native dairy breed were 38.9% and 24.0%, respectively, whereas those in female and male Holstein-Friesian breed were 4.2% and 0%, respectively. The first internal transcribed spacer (ITS1) region of G. pulchrum rDNA showed an intra-individual variation in the sequence and length, and the variation was ascribed to some unstable repeats of "A" or "CA".
Distinct incidences of G. pulchrum infection in native dairy breed and Holstein-Friesian breed might be ascribed to different animal husbandry manners for each breed in Iran; the former breed grazes freely in the pasture, but the latter breed is usually held in a pen. The rDNA sequence of Iranian G. pulchrum, obtained for the first time by us, might facilitate a reliable species identification of the parasite with a wide spectrum of morphological variations.
美丽筒线虫（Gongylonema pulchrum Molin，1857）是一种丝状旋尾线虫，在世界各地的多种哺乳动物体内均有发现。尚未有关于伊朗不同品种或年龄牛群中该线虫感染率的报道。本研究旨在揭示伊朗北部地区屠宰牛群中美丽筒线虫的感染状况。
2006年3月至2007年8月期间，在伊朗北部马赞德兰省的四个当地屠宰场收集了97头本地奶牛品种和41头荷斯坦-弗里生品种奶牛的完整食管，并进行寄生虫学检查。通过PCR扩增rDNA小亚基和大亚基的八个重叠片段，并对获得的核苷酸序列进行特征分析。
本地奶牛品种中，雌性和雄性的美丽筒线虫感染率分别为38.9%和24.0%，而荷斯坦-弗里生品种中，雌性和雄性的感染率分别为4.2%和0%。美丽筒线虫rDNA的第一个内部转录间隔区（ITS1）在序列和长度上存在个体内变异，该变异归因于“A”或“CA”的一些不稳定重复序列。
本地奶牛品种和荷斯坦-弗里生品种中美丽筒线虫感染率的差异可能归因于伊朗各品种不同的畜牧方式；前者在牧场自由放牧，而后者通常圈养。我们首次获得的伊朗美丽筒线虫rDNA序列可能有助于对具有广泛形态变异的该寄生虫进行可靠的物种鉴定。
