Chikowore Tatenda J, Zishiri Oliver T, Mukaratirwa Samson
Discipline of Genetics, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Durban.
Onderstepoort J Vet Res. 2019 Jun 18;86(1):e1-e11. doi: 10.4102/ojvr.v86i1.1706.
Fasciola spp. are the causative agents of fascioliasis in humans and livestock. Before the development of control and management measures, the geographical distribution of the species and patterns of infection must be considered. Because of difficulties in the phenotypic differentiation and morphometric classification of Fasciola spp., DNA molecular markers have become more useful for fluke differentiation and description of phylogenetic patterns. This study aimed to differentiate and describe the phylogenetic background of Fasciola spp. isolated from cattle slaughtered at three abattoirs in the Mpumalanga and KwaZulu-Natal provinces of South Africa. The cytochrome c oxidase I (COI) - FHCO1 (forward: 5'-TTGGTTTTTTGGGCATCCT-3') and FHCO1 (reverse: 5' -AGGCCACCACCAAATAAAAGA3') - marker was sequenced from 55 Fasciola flukes that were collected from abattoirs in catchment areas of the KwaZulu-Natal and Mpumalanga provinces. Fasciola hepatica was demonstrated to have 100% prevalence in KwaZulu-Natal and Mpumalanga (highveld), respectively, and 76% prevalence in the lowveld (Belfast area) of Mpumalanga. Two animals from the Belfast metapopulation were co-infected with both Fasciola gigantica and F. hepatica. DNA sequence analysis of all the isolates demonstrated a sequence conservation of 0.472, nucleotide diversity of 0.082 and Tajima's D of -1.100; however, it was not statistically significant (p > 0.05). Twenty-two haplotypes were identified, with 18 novel haplotypes being unique to the isolates from South Africa. Within the study samples, 12 haplotypes were isolated to a few individuals, with a haplotype diversity of 0.8957 indicating high genetic diversity. Principal coordinate analysis supported the clustering and distribution of the haplotypes, with 11.38% of the variation being attributed to coordinate 2 and 55.52% to coordinate 1. The distribution of Fasciola spp. has been demonstrated to be related to the distribution of the freshwater intermediate host snails, Lymnaea spp., as well as the relative altitude of the localities in South Africa. Information provided by this study serves as preliminary evidence for further studies on the mapping of the distribution of F. gigantica and F. hepatica in South Africa, which is key in designing control programmes for fascioliasis in humans and livestock.
片形吸虫属是人和家畜肝片吸虫病的病原体。在制定控制和管理措施之前，必须考虑该物种的地理分布和感染模式。由于片形吸虫属在表型分化和形态计量分类方面存在困难，DNA分子标记在吸虫分化和系统发育模式描述中变得更加有用。本研究旨在区分和描述从南非姆普马兰加省和夸祖鲁 - 纳塔尔省三个屠宰场宰杀的牛身上分离出的片形吸虫属的系统发育背景。对从夸祖鲁 - 纳塔尔省和姆普马兰加省集水区的屠宰场收集的55条片形吸虫的细胞色素c氧化酶I（COI） - FHCO1（正向：5'-TTGGTTTTTTGGGCATCCT-3'）和FHCO1（反向：5' -AGGCCACCACCAAATAAAAGA3'）标记进行了测序。结果表明，肝片吸虫在夸祖鲁 - 纳塔尔省和姆普马兰加省（高地）的感染率分别为100%，在姆普马兰加省低地（贝尔法斯特地区）的感染率为76%。来自贝尔法斯特复合种群的两只动物同时感染了巨片吸虫和肝片吸虫。对所有分离株的DNA序列分析显示，序列保守性为0.472，核苷酸多样性为0.082， Tajima's D为 -1.100；然而，差异无统计学意义（p>0.05）。鉴定出22个单倍型，其中18个新单倍型是南非分离株所特有的。在研究样本中，12个单倍型仅存在于少数个体中，单倍型多样性为0.8957，表明遗传多样性高。主坐标分析支持单倍型的聚类和分布，11.38%的变异归因于坐标2，55.52%归因于坐标1。已证明片形吸虫属的分布与淡水中间宿主蜗牛（椎实螺属）的分布以及南非各地区的相对海拔有关。本研究提供的信息为进一步研究南非巨片吸虫和肝片吸虫的分布图谱提供了初步证据，这对设计人类和家畜肝片吸虫病的控制方案至关重要。
