Taenia asiatica: Historical overview of taeniasis and cysticercosis with molecular characterization.

Asian Taenia is a human-infecting Taenia tapeworm known as Taenia asiatica following morphological examination of adult and larval stages of the tapeworm by Eom and Rim (1993). The life cycle of T. asiatica differs from that of T. saginata in its intermediate host (pigs versus cattle) as well as in the infected organs (liver versus muscle). T. asiatica can be differentiated from T. solium and T. saginata by examination of morphological characteristics such as the scolex, mature and gravid proglottids in the adult stage, and the scolex and bladder surface in the larval stage. T. asiatica has been identified in Korea, Taiwan, the Philippines, China, Thailand, Indonesia, Vietnam, Japan, Lao PDR, Nepal and India. The molecular tools employed for T. asiatica identification have been developed to differentiate T. asiatica from other human-infecting Taenia tapeworms based on genetic information such as nucleotide sequence of mitochondrial genes, nuclear ribosomal genes and nuclear genes that lead to development of the subsequent molecular techniques, such as PCR-RFLP, PCR-RAPD, BESST-base, LAMP and qPCR. Investigation of the phylogenetic relationships among human Taenia species revealed that T. asiatica is a sister species with T. saginata, which is genetically more similar than other Taenia species in terms of the nucleotide sequences of cox1, nad1 and 28S rDNA. The mitochondrial genomes of human Taenia tapeworms comprise 13,703bp (T. asiatica), 13,670bp (T. saginata) and 13,709bp (T. solium), and contain 36 genes including 12 protein-coding genes, 2 ribosomal RNAs (rRNAs, a small and a large subunit), and 22 transfer RNAs (tRNAs). Sequence differences in the full genome of T. asiatica and T. saginata mitochondria is 4.6%, while T. solium differs by 11%. Hox gene orthology in T. asiatica was established by comparative analysis with Platyhelminthes Hox genes. T. asiatica Hox revealed six Hox orthologs including two lab/Hox1, two Hox3, one Dfd/Hox4 and one Lox/Lox4. Hybridization between T. asiatica and T. saginata was definitely observed in these species which are sympatrically endemic in the regions of Korea, Thailand, China and Lao PDR. Comparative analyses of T. asiatica, T. saginata and T. solium genomes were also reported with genome features. Taenia asiaticus nomen novum was proposed for T. asiaticaEom and Rim, 1993 which is a homonym of T. asiatica Linstow, 1901 (Davaineidae).

Human Tapeworm from Simalungun, Indonesia.

A 46-years-old man from Indonesia, resides in Nagori Dolok Village, Silau Kahaean Subdistrict, Simalungun District, Sumatra Utara Province, had of spontaneous discharge of tapeworm segments (proglottids) from anus almost every day for ten years. There were 1-5 segments which can move actively discharge per day. Although he feels embarrassed about the condition, no significant symptoms were found, and physical examination was within normal limits. Clinical diagnosis of Taeniasis was made on October 20, 2017, and subsequently received oral Praziquantel 600 mg tablet single dose and 5 mg of oral Bisacodyl. Four hours later, the patient was defecated. The stool was collected in plastic and filtered with a filter device to collect any tapeworm segments.A full segment of tapeworm as long as 2.86 meters were found. Microscopic examination was done to identify the egg worms, proglottids, and scolex. Dye substance was injected into a mature gravid proglottid through the genital pore and pressed in two object-glasses to identify the reproductive organs. Microscopic examination (400x magnification) of this sample revealed that the number of uterine branches and testes in a proglottid were 16 pairs. The number of uterine branches in T. solium are 8-12 pairs and T. saginata are 18-32 pairs.The filtered stool was moved into a container and carefully observed. A soft yellowish-white material of 1.5 mm in diameter was found, which turned out to be the head of the tapeworm called Scolex. Microscopic examination of scolex revealed that the rostellum was absent. A segment called 'snout' was found at the apex. The functions were probably as a sense of smell and vacuum organ.The patient was lived in Simalungun, North Sumatera, some tribe in that area has a long tradition of culinary called 'Hinasumba', consist of raw pork liver and meat, and 'Naiholat' consist of poorly cooked pork.Even though pig was determined as an intermediate host, the type of tapeworm was not consistent with T.solium. The patient had the long history of infection but never had sign or symptoms of neurocystecercosis. Based on etno-geographical condition, the patient was infected by T.asiatica. Microscopic examination of the uterus and scolex indicate that the tapeworm had most similarity to T.asiatica.Amin et al.8 from Bangladesh in 2009 reported a case of T. asiatica in human with total strobila length was 1.5 meters. Macroscopic morphology (length:width) of gravid proglottid segment of T.saginata is 3:1, T. solium 1.5:1. The tapeworm that we discovered had 1-1.5:1 ratio (2.5 cm length and 2 cm width).Some features of the tapeworm (no rostellum, present of the snout, and fix number of theuterus in every proglottid) were not found in three existing type of Taenia species. Further microscopic and molecular study should be done to determined type or subtype of the tapeworm. A case of taeniasis asiatica who had completed treatment was reported. Macroscopic and microscopic was done to support the clinical diagnosis.

A comparison of ancient parasites as seen from archeological contexts and early medical texts in China.

This paper integrates our knowledge from traditional Chinese medical texts and archeological findings to discuss parasitic loads in early China. Many studies have documented that several different species of eukaryotic endoparasites were present in early human populations throughout China. Nevertheless, comprehensive paleoparasitological records from China are patchy, largely due to taphonomic and environmental factors. An examination of early Chinese medical texts allows us to fill in some of the gaps and counteract apparent biases in the current archeoparasitological records. By integrating the findings of paleoparasitology with historic textual sources, we show that parasites have been affecting the lives of humans in China since ancient times. We discuss the presence and prevalence of three groups of parasites in ancient China: roundworm (Ascaris lumbricoides), Asian schistosoma (Schistosoma japonicum), and tapeworm (Taenia sp.). We also examine possible factors that favored the spread of these endoparasites among early humans. Therefore, this paper not only aims to reveal how humans have been affected by endoparasites, but also addresses how early medical knowledge developed to cope with the parasitic diseases.

Genetic and morphometric categorization of Taenia ovis from Sheep in Iran.

Little is known about the genetic and morphological characters of Taenia ovis. The purpose of the present study was to characterize sheep isolates of T. ovis using rostellar hook morphometry as well as mitochondrial genes sequence analysis. Ninety sheep specimens of Cysticercus ovis were collected from 18 slaughterhouses in Iran. The mean ± s.d. for total length of large and small hooks were 174.1 ± 6.4 and 116.7 ± 5.4 µm, respectively. CO1 and 12S rRNA sequence analysis showed 11 and nine haplotypes, respectively. The level of pairwise nucleotide variations between individual haplotypes of CO1 and 12S rRNA genes were 0.3-1.1 and 0.2-1.0%, respectively. Level of nucleotide variation in CO1 and 12S rRNA between T. ovis haplotypes from present study and eight other Taenia species was found to be 11.3-17.8 and 5.3-16.3%, respectively. Phylogenetic analysis clustered all T. ovis isolates into a single clade comprised of the all CO1 and 12S rRNA haplotypes. CO1 nucleotide difference between T. ovis ovis and T. asiatica was 13.6% that is lesser than the corresponding difference between T. ovis ovis and T. ovis krabbei, warranting the designation of two separate species as T. ovis and T. krabbei. Interclass correlation coefficients showed that there was no significant association between rostellar hook length variation and the variability of the mitochondrial genes.

A Case of Coenurosis in a Wild Rabbit (Lepus sinensis) Caused by Taenia serialis Metacestode in Qinghai Tibetan Plateau Area, China.

Six cystic metacestodes were found in the abdominal muscles of a wild rabbit, Lepus sinensis, in China. The coenurus contained one or more scolices armed with hooklets. Mitochondrial cox1 (1,623 bp) confirmed 98% homology with cox1 of Taenia serialis. This is the first report of T. serialis infection in an intermediate host in the Qinghai Tibetan Plateau Area, China.

The alpaca (Vicugna pacos) as a natural intermediate host of Taenia omissa (Cestoda: Taeniidae).

Three metacestodes were collected from the mesentery and the surface of the liver of three adult alpacas (Vicugna pacos) in a slaughterhouse located in Puno, Peru. Various features of the metacestodes were observed for morphological identification. A molecular diagnosis was performed by PCR-based sequencing of mitochondrial genes of cytochrome c oxidase subunit 1 (cox1) and the NADH dehydrogenase subunit 1 (nad1). All metacestodes were identified as Taenia omissa by morphology and molecular methods The isolates from alpacas showed significant sequence similarity with previously reported isolates of T. omissa (95.7-98.1% in cox1 and 94.6-95.1% in nad1). Our report is the first to detect T. omissa metacestodes in alpacas and to reveal that alpacas are natural intermediate hosts for this parasite.

The first outbreak of Taenia ovis infection in China.

Infection of Taenia ovis metacestodes in sheep or goats causes great economic losses due to condemnation of carcasses. T. ovis infection is not formally recorded in China to date. In October, 2015, T. ovis infection occurred in Jingtai County, China, and 113 of 192 sheep from one farm were infected. Cysts resided in the cardiac and skeletal muscle, and evaginated metacestodes had four suckers and scolex armed with approximately 23 hooks. Using cox1 and nad1 as molecular markers, the sample was further identified and the results showed that the cox1 and nad1 nucleotide sequences of the sample shared 99% identity with that of T. ovis and 75%-91.3% with those of other Taenia species. Taken together, these results confirm the first occurrence of T. ovis in China.

Abnormalities in the WFU strain of Taenia crassiceps (Cyclophyllidea: Taeniidae) following years of propagation in mice.

Asexually proliferating Taenia crassiceps (Zeder, 1800) metacestodes isolated within past decades have been successfully sub-cultured under experimental conditions using Mus musculus Linnaeus, 1758 mice. However, during their development, morphological irregularities of scolex structures have been reported in two of the three strains of this cestode species maintained in mice - ORF and KBS. The main goal of this work is to describe the abnormalities observed in a sample of 118 cysticerci of the third T. crassiceps strain used at present - WFU. Morphological abnormalities were detected in 39.8% of the evaginated scoleces; they consisted of supernumerary suckers (n= 2), duplicated (n= 2) or absent rostellum (n= 1), as well as absent or aberrant (n= 29) hooks, which were significantly shorter when compared to the large and short hook lengths referred to in the literature.

Cerebral and non-cerebral coenurosis in small ruminants.

Cerebral coenurosis is caused by Coenurus cerebralis, the larval stage of Taenia multiceps. The metacestode causes severe lesions in the brain and spinal cord of the intermediate host, so-called "gid" or "stagger" disease. Whereas, the non-cerebral coenurosis caused by Coenurus gaigeri, the larval stage of Taenia gaigeri, particularly affects goats. The cyst form of the Taenia gaigeri is found in intramuscular and subcutaneous tissues. The difference in the sequence of mitochondrial genes of cox1 and nadI and also other variations reported for clinical, morphological and pathological aspects in coenurosis lead to the hypothesis that there is genetic intraspecific variability within this species, such as in other members of the genus Taenia. Nevertheless, it has been shown that sheep and goats have been infected by both cerebral and non-cerebral coenurosis and it has been suggested that such cerebral and non-cerebral metacestodes may belong to different species of Taenia which are host specific for these hosts.

RCB20, an experimental benzimidazole derivative, affects tubulin expression and induces gross anatomical changes in Taenia crassiceps cysticerci.

Helminth ß-tubulins are the targets of benzimidazole (BZM) carbamate compounds. The specificity of the interactions between such compounds and their in vivo targets depends on the presence of specific amino acid residues in the target molecules. To discover new and effective anthelmintic drugs, we used a medicinal chemistry approach to synthesize a series of BZM derivatives that exploited the BZM moiety as a template. We have previously found that one compound, 2-(trifluoromethyl)-1H-benzimidazole (RCB20), has better in vitro and in vivo activity than albendazole sulfoxide (ABZSO). In the present study, the effect of RCB20 and ABZSO treatment on expression of Taenia crassiceps cysticerci cytoskeletal proteins such as actin, myosin II, and tubulin isoforms was examined. The effects of RCB20 and ABZSO after 11 days treatment of the parasites was evaluated by light, confocal, and electron microscopy, and by immunochemistry and immunohistochemistry. The RCB20-induced effects were more rapid than the ABZSO-induced effects on the parasites. In the RCB20-treated parasites, we observed gross-structural damage at the whole parasite level, particularly in the inner tissues and flame cells. Changes in the expression patterns of the cytoskeletal proteins, as assessed by immunohistochemistry and immunoblotting, revealed that the most important drug-induced effect on the parasites was a reduction in the expression level of tyrosinated α-tubulins. Our research findings suggest that RCB20 treatment affected posttranslational modification of parasite α-tubulin molecules, which involved removal of the α-tubulin carboxy-terminal tyrosine.

Discovery of taeniid eggs from a 17th century tomb in Korea.

Even though Taenia spp. eggs are occasionally discovered from archeological remains around the world, these eggs have never been discovered in ancient samples from Korea. When we attempted to re-examine the archeological samples maintained in our collection, the eggs of Taenia spp., 5 in total number, were recovered from a tomb of Gongju-si. The eggs had radially striated embryophore, and 37.5-40.0 µm×37.5 µm in size. This is the first report on taeniid eggs from ancient samples of Korea, and it is suggested that intensive examination of voluminous archeological samples should be needed for identification of Taenia spp.

Taenia arctos n. sp. (Cestoda: Cyclophyllidea: Taeniidae) from its definitive (brown bear Ursus arctos Linnaeus) and intermediate (moose/elk Alces spp.) hosts.

Taenia arctos n. sp. (Cestoda: Cyclophyllidea: Taeniidae) is described from the brown bear Ursus arctos Linnaeus (definitive host) and moose/elk Alces spp. (intermediate hosts) from Finland (type-locality) and Alaska, USA. The independent status of the new species and the conspecificity of its adults and metacestodes have been recently confirmed by the mtDNA sequence data of Lavikainen et al. (2011; Parasitology International, 60, 289-295). Special reference is given to morphological differences between the new species and T. krabbei Moniez, 1879 (definitive hosts primarily canines for the latter), both of which use the moose/elk (Alces spp.) as intermediate hosts (the latter also uses Rangifer and perhaps other northern ruminants), and between the new species and T. ursina Linstow, 1893, both of which use the brown bear U. arctos as a definitive host. New morphological data are also provided for adults and cysticerci of T. krabbei. The analysis includes potentially useful morphometric features that have not been previously applied to Taenia spp.

Discovery of Taeniid Eggs from A 17th Century Tomb in Korea

Even though Taenia spp. eggs are occasionally discovered from archeological remains around the world, these eggs have never been discovered in ancient samples from Korea. When we attempted to re-examine the archeological samples maintained in our collection, the eggs of Taenia spp., 5 in total number, were recovered from a tomb of Gongju-si. The eggs had radially striated embryophore, and 37.5-40.0 micromx37.5 microm in size. This is the first report on taeniid eggs from ancient samples of Korea, and it is suggested that intensive examination of voluminous archeological samples should be needed for identification of Taenia spp.

Ultrastructural reconstruction of Taenia ovis oncospheres from serial sections.

The cellular organisation of Taenia ovis oncospheres is interpreted from ultrathin serial sections and transmission electron microscopy following high pressure freezing and freeze-substitution. The surface of a hatched, non-activated T. ovis oncosphere is covered by an oncospheral membrane below which is the tegument bearing microvilli. The basal lamina of the tegument is underlain by broad bands of peripheral somatic musculature. Three pairs of hooks and associated muscles are present in the somatophoric third of the oncosphere. Approximately 19 cells of seven different types were identified which include: (i) a quadri-nucleated syncytium of penetration gland type 1 containing two lateral pairs of cell bodies interconnected by narrow cytoplasmic bridges (PG1); (ii) a quadri-nucleated syncytium of penetration gland type 2 (PG2); (iii) a single-nucleated median mesophoric gland cell; (iv) 10 somatic cells; (v) two germinative cells; (vi) two nerve cells; and (vii) a pair of median somatophoric cells. This study provides a clear understanding of the morphology of T. ovis oncospheres and forms the basis for further investigations into the biology of taeniid oncospheres.

Pathological, molecular, and biochemical characterization of Coenurus gaigeri in Iranian native goats.

Coenurus gaigeri is the larval stage of Taenia multiceps gaigeri, which infects the muscles of goats and, to a lesser extent, sheep. Metacestodes of the goat such as Coenurus cerebralis, Cysticercus tenuicollis, Cysticercus ovis, and hydatid cysts have been extensively studied. However, because of the uncommon occurrence of C. gaigeri, very few records exist of its biology, pathogenesis, and pathology. Therefore, an investigation was conducted in the summer of 2008 at Shiraz Slaughterhouse, where 2.6% of the goats were infected with intramuscular cysts. Scolices from coenuri were collected for morphologic analysis, and the cysts were identified as C. gaigeri, the intermediate stage of T. multiceps gaigeri. In addition, molecular genetic markers of mitochondrial DNA were applied phylogenetically to resolve the questionable relationship between C. gaigeri and C. cerebralis. All coenuri fluids were aspirated and centrifuged separately; the supernatants were analyzed for biochemical features that included glucose, total protein, urea nitrogen, uric acid, triglycerides, cholesterol, creatinine, calcium, sodium, potassium, alanine aminotransferase, and aspartate aminotransferase. The pathologic changes around the coenuri included mechanical destruction of the affected tissues, associated with degenerative and necrotic changes, infiltration by polymorphonuclear and mononuclear cells, proliferation of fibroblasts, and development of adventitious tissue. Results based on phylogenetic analysis of the mitochondrial DNA (CO1 and ND1) suggest that the larval stages of T. multiceps gaigeri and C. cerebralis, which showed similar morphological criteria, are monophyletic species. However, C. gaigeri interestingly were situated in the biceps femoris, triceps, and abdominal muscles without localization in the nervous system.

Mitochondrial DNA data reveal cryptic species within Taenia krabbei.

Cysticerci of Taenia sp. from two elks (Alces alces) in Finland were characterized using morphological criteria and sequences of two mitochondrial DNA regions. The host species, size, structure and location of the cysticerci indicated that they might belong to Taenia krabbei, a circumpolar species occurring in a sylvatic life cycle in wild canids and cervids. Based on the number, length and shape of the rostellar hooks, the specimens could not be unambiguously defined as belonging to T. krabbei, T. cervi, T. ovis or T. solium. In the phylogenetic analysis, based on mitochondrial nucleotide sequence data, Taenia sp. was placed as a sister species of T. solium, distant from T. krabbei isolates previously characterized from Svalbard. This indicates that the Finnish and the Svalbard isolates, resembling T. krabbei, cannot represent a single species. The results suggest that careful morphological and genetic analyses of further isolates from intermediate and definitive hosts are required to define the taxonomic status of these two cryptic species.

Antimicrobial peptides (Temporin A and Iseganan IB-367): effect on the cysticerci of Taenia crassiceps.

Taenia solium infections continue being a health problem in undeveloped countries, and few effective control measures against this parasite are being applied. Antimicrobial peptides (AMPs) belong to the innate immune response and capable of destroying pathogens. We tested the ability of two AMPs, Temporin A (TA) and Iseganan IB-367 (IB-367) to damage T. crassiceps cysticerci in vitro. Doses of 200 and 400 microg/ml of TA and IB-367 caused cysticerci to shrink, lose motility, the formation of macrovesicles in the tegument, as well as decreased evagination properties. These changes were observed as early as 3-6h and became more pronounced over 24h, when the morphological changes of the bladders became evident by both light and electron microscopy. Electron micrographs of cysticerci exposed to peptides showed initial changes as collapsed microvesicles in the tegument, with formation of large vesicles and extrusion of tegumentary tissues into the surrounding media, which led to complete loss of the tegument as well as shrinkage and complete loss of structure of parenchymal tissue after 24h. Peptides administered to cysticercotic mice one month post-infection in a single intraperitoneal dose of 200 or 400 microg, reduced the parasite load by 25% for IB-367, and 50% for TA. The humoral response of infected mice does not appear capable of killing surviving cysticerci. Our studies show that in vitro, AMPs severely damage the tegument and the scolex, and open a new pathway for biological drug design or the development of transgenic animals that over express these peptides capable of killing the cysticerci in vivo.

Human tapeworms in north Vietnam.

Sixty-five Taenia samples were collected from patients in a referral hospital in Hanoi, north Vietnam, for species identification by morphological and molecular techniques. PCR-RFLP of a mitochondrial 12S rDNA fragment, developed for this study, allowed direct differentiation between all Taenia spp., overcoming the disadvantages of classical morphological examination, which failed on disintegrated samples. Taenia saginata asiatica was the most common species (55.4%) followed by T. saginata (38.5%) and T. solium (6.2%). This report demonstrates the complexity of the epidemiology of Taenia spp. in Vietnam and the need for further work to reveal transmission patterns of these species.