Teniases caused by Taenia asiatica, Taenia saginata, Taenia solium

The urgency of the problem of human teniases is due to the widespread prevalence of these parasitoses, which often infect humans.The aim and result of the work is to summarize the available information about the etiology, epidemiology, pathogenesis, clinical picture, diagnosis, etiotropic therapy and prevention of human teniases.Conclusion. Teniases are widespread, including on the territory of Russia. The clinic mainly includes symptoms of lesions of the gastrointestinal tract, allergic reactions. Diagnostics is carried out on the basis of the detection of eggs, proglottids, coproangigens of parasites in the feces, serological and molecular genetic tests. Praziquantel is an effective etiotropic therapy. Prevention takes into account the peculiarities of the epidemiology of teniases.

Occurrence of a Hybrid Between Taenia saginata and Taenia asiatica Tapeworms in Cambodia

Human infection with <i>Taenia asiatica</i> or a hybrid between <i>Taenia saginata<i> and <i>T. asiatica</i> has not been reported in Cambodia. We detected for the first time a hybrid form between <i>T. saginata</i> and <i>T. asiatica</i> in Preah Vihear Province, Cambodia. An adult tapeworm specimen, i.e., 75 cm long strobila without scolex, was expelled from a 27-year-old man after praziquantel medication and purging. It was morphologically indistinguishable between <i>T. saginata</i> and <i>T. asiatica</i>. Several proglottids were molecularly analyzed to confirm the tapeworm species. The mitochondrial gene encoding cytochrome <i>c</i> oxidase subunit 1 (<i>cox</i>1) and nuclear genes encoding elongation factor-1α (<i>ef1</i>) and ezrin-radixin-moesin (ERM)-like protein (<i>elp</i>) were sequenced, and a single-allele analysis was performed to confirm the haploid genotype. The results revealed that our sample showed a discrepancy between the mitochondrial and 2 nuclear genes. It possessed homozygous sequences typical of <i>T. saginata</i> at <i>cox</i>1 and <i>ef1</i> loci. However, it was heterozygous at the <i>elp</i> locus, with 1 allele in <i>T. asiatica (elpA)</i> and 1 in <i>T. saginata (elpC</i>), which indicates that it is a hybrid between <i>T. saginata</i> and <i>T. asiatica</i>. The present results confirmed the presence of a hybrid between <i>T. saginata</i> and <i>T. asiatica</i> in Cambodia and strongly suggest the existence of also ‘pure’ <i>T. asiatica</i> in Cambodia.

Molecular Diagnosis of a Hybridized Tapeworm (Between Taenia Saginata and Taenia Asiatica) Infection Case in Yunnan, China, 2019

Human taeniasis is still prevalent in many countries in the world and affecting human health. Three species of tapeworms in the genus Taenia, including Taenia asiatica, Taenia saginata, and Taenia solium are the most common pathogens for the diseases. The genetic relationships of T. saginata and T. asiatica are close. The natural hybridization between these two has not been clinically diagnosed in China. In this study, we report an 18-year-old male patient with taeniasis hospitalized in Yunnan, China, in 2019. The patient was treated with traditional Chinese medicine, and a tapeworm around 2.7 m long was expelled. The morphology of egg and gravid proglottid of the tapeworm were revealed. More interesting is that the tapeworm was identified as a T. saginata-T. asiatica hybridized by the molecularly and phylogenetic analysis. The case study reported the first human taeniasis caused by the T. saginata and T. asiatica hybridization and suggested that the new types of hybridized taeniases exist in China and further investigation and research on the pathogens in Yunnan is needed.

Medical Parasitology Taxonomy Update, January 2018-May 2020

The taxonomy of parasites of medical and public health importance is rapidly evolving. This mini-review provides an update of taxonomic revisions and additions in the field of medical parasitology from January 2018-May 2020. Several established human parasites have been reassigned in genera over the past two years, while a number of novel parasites of humans have been identified. A comprehensive summary of these changes is provided here and Taenia suihominis is proposed as a replacement name for Taenia asiaticus Eon et al., which is a homonym of Taenia asiatica von Linstow.

Molecular Diagnosis of Taenia saginata Tapeworms from Two Residents of Northern Cambodia

<i>Taenia saginata</i> infection has seldom been reported in Cambodia. In this study, we performed a survey of intestinal parasites in 1,156 residents of Preah Vihear and Stung Treng Provinces in 2018. The results revealed that 26 (2.4%) cases were positive for Taenia spp. eggs. In order to obtain the strobilae of the tapeworms, 2 patients in Preah Vihear were treated with praziquantel and purged with magnesium salts. The proglottids expelled after the medication were morphologically and molecularly analyzed to determine the species. The main uterine lateral braches in gravid proglottids were >15 in number suggesting that they are either <i>T. saginata</i> or <i>Taenia asiatica</i>. The sequences of the mitochondrial cytochrome c oxidase subunit 1 (<i>cox1</i>) gene and 2 nuclear loci, elongation factor-1 alpha (<i>ef1</i>) and ezrin-radixin-moesin-like protein (<i>elp</i>), were identical to the sequences of <i>T. saginata</i> available in GenBank but distant from <i>Taenia solium</i>, <i>T. asiatica</i>, and <i>T. saginata</i>-<i>T. asiatica</i> hybrid. This is the first report of the presence of <i>T. saginata</i> in the northern part of Cambodia bordering Lao PDR based on a molecular confirmation.