Department of Medical Parasitology & Mycology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.
Infectious and Tropical Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
Comp Immunol Microbiol Infect Dis. 2020 Dec;73:101566. doi: 10.1016/j.cimid.2020.101566. Epub 2020 Oct 22.
Cattle are intermediate host for several species of Sarcocystis, including S. cruzi, S. hirsuta, and S. hominis with high prevalence worldwide. The present study aimed to determine the prevalence of Sarcocystis infection, species identification, and phylogenetic analysis of the parasite in cattle in Northwest Iran. The samples of diaphragm and esophagus from 290 cattle were collected from slaughterhouses in Northwest Iran and subjected to macroscopic, microscopic, and histopathology examinations, PCR-RFLP, sequencing and phylogenetic analyses. Tissue cysts of Sarcocystis spp. were detected in 92% of cattle by digestion and microscopic tests. Based on the PCR-RFLP and specific PCR, 87.9% and 1.03% of isolates were identified as S. cruzi, and S. hominis, respectively. Macrocyst was seen in a single sample that was identified as S. gigantea. The haplotype network exhibited the extension of the various haplotypes of S. cruzi between neighboring provinces in Northwest Iran. Heterogeneity analysis of S. cruzi 18S-rRNA sequences indicated genetic diversity among S. cruzi isolates (Haplotype diversity: 0.733-0.854) consisting 16 haplotypes; however, the nucleotide differences showed low diversity (0.01481 to 0.03351). Pair wise sequence distance matrix amongst S. cruzi sequences indicated an intra-species divergence of 0%-7.8% and identity of 92.6%-100%. Sarcocystis infection is highly prevalent in cattle in Northwest Iran, with the predominance of S. cruzi, and genetic variants of this species are unequivocally distributing in Northwest provinces. First global detection of S. gigantea in cattle reflects new insights of transmission dynamic and biology of this parasite in Iran.
牛是几种肉孢子虫的中间宿主，包括在全球广泛流行的克氏肉孢子虫、粗纹肉孢子虫和人型肉孢子虫。本研究旨在确定伊朗西北部牛的肉孢子虫感染流行率、种属鉴定和寄生虫的系统发育分析。从伊朗西北部的屠宰场采集了 290 头牛的膈肌和食管样本，进行了宏观、微观和组织病理学检查、PCR-RFLP、测序和系统发育分析。通过消化和显微镜检查，在 92%的牛中检测到肉孢子虫属的组织包囊。根据 PCR-RFLP 和特异性 PCR，87.9%和 1.03%的分离株分别鉴定为克氏肉孢子虫和人型肉孢子虫。在单个样本中观察到巨孢囊，鉴定为 giant 肉孢子虫。单倍型网络显示了伊朗西北部邻近省份之间各种克氏肉孢子虫单倍型的延伸。克氏肉孢子虫 18S-rRNA 序列的异质性分析表明克氏肉孢子虫分离株之间存在遗传多样性（单倍型多样性：0.733-0.854），由 16 个单倍型组成；然而，核苷酸差异显示出低多样性（0.01481 至 0.03351）。克氏肉孢子虫序列之间的成对序列距离矩阵表明种内分化为 0%-7.8%，同一性为 92.6%-100%。伊朗西北部牛的肉孢子虫感染非常普遍，以克氏肉孢子虫为主，该种的遗传变异明确分布在西北部各省。在牛中首次全球检测到 giant 肉孢子虫反映了该寄生虫在伊朗传播动态和生物学的新见解。
