• Parasites, Hosts and Diseases
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• 제31권1호
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• pp.1-6
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• 1993

현재 인체에는 기새하는 Taenia 조충으로는 돼지고기 유구낭미층(Cysticercus cellulosae)을 먹어서 감염되는 Taenia solium Linnaeus 1785과 쇠고기의 무구낭미층(Cysticercus bovis)을 먹어서 감염되는 Taenia saginata Goeze 1782 두 종이 알려져 있다. 한편 인체에 기생하는 제 3의 Taenia 조충으로 최근 타이완, 한국, 인도내시아, 태국, 필리핀 등 아시아국가를 중심으로 발견되는 Asian Taenia saginata 조충은 돼지나 소의 간 또는 내장에 있는 내장형낭미충을 먹어서 감염되는 것으로 추정된다. 그러나 이러한 생활사상의 구분에도 불구하고 형태하적으로는 본충이 Taenia saginate Groeze 1782와 유사하기 때문에 아직 신종으로 인정되지 않은 상태이다. 이에 연구자들은 Asian Taenia saginata 조충의 형태학적 구분점을 새로이 발견하고 학명으로서 Taenia asiatica sp.n.(한국명:아시아조총)을 제시하고자 한다. 감별적으로는 1.선충의 두절에 있는 액취의 존재, 2. 성충의 수태편절에서 관찰되는 자궁세지의 수, 3.성충의 수태관절에서 관찰되는 미돌기의 존재 및 4.유추의 낭벽표면에서 관찰되는 사마귀양 구조가 광학 및 전자현경적으로 관찰되었다. 이중 '자궁세지'와 '미돌기'는 새로이 관찰하여 기재하는 구조물로서 처음으로 Taeniid의 종감별에 사용하였다.

• Parasites, Hosts and Diseases
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• 제51권1호
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• pp.37-42
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• 2013

Taeniasis is prevalent in all regions of Thailand, except the South. Infections were more frequently found in males than females of any age from 7-83 years. Taenia saginata is the most common species throughout the country. Taenia asiatica was reported only in the province of Kanchanaburi in the Central region. Co-infections, with Taenia solium and T. asiatica or T. solium and T. saginata, were found. Hybridization between T. asiatica and T. saginata is evidence that co-infection is never found between these 2 species. Finding more than 1 worm in a single patient was not entirely rare. Genetic variation was found without correlation to its geographic distribution in T. saginata, whereas no variation was found in T. asiatica.

• Parasites, Hosts and Diseases
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• 제59권2호
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• pp.179-182
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• 2021

Human infection with Taenia asiatica or a hybrid between Taenia saginata and T. asiatica has not been reported in Cambodia. We detected for the first time a hybrid form between T. saginata and T. asiatica 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 T. saginata and T. asiatica. Several proglottids were molecularly analyzed to confirm the tapeworm species. The mitochondrial gene encoding cytochrome c oxidase subunit 1 (cox1) and nuclear genes encoding elongation factor-1α (ef1) and ezrin-radixin-moesin (ERM)-like protein (elp) 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 T. saginata at cox1 and ef1 loci. However, it was heterozygous at the elp locus, with 1 allele in T. asiatica (elpA) and 1 in T. saginata (elpC), which indicates that it is a hybrid between T. saginata and T. asiatica. The present results confirmed the presence of a hybrid between T. saginata and T. asiatica in Cambodia and strongly suggest the existence of also 'pure' T. asiatica in Cambodia.

• Parasites, Hosts and Diseases
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• 제47권1호
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• pp.73-77
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• 2009

Differential diagnosis of Taenia asiatica infection from other human taeniases by serology has been tested. An enzyme-linked immunoelectrotransfer blot (EITB) was applied to subjected human sera and tapeworm materials. Thirty-eight proteins reactive to serum IgG were observed between 121 and 10 kDa in adult worms, and more than 22 serum-reactive components between 97kDa and 21.5kDa were observed in eggs of T. asiatica. Antigens of adult T. asiatica revealed immunoblot bands between 120 and 21.5 kDa against T. asiatica infected sera. Antigens of adult Taenia saginata revealed 110-100, 66, 58-56, and 46 kDa immunoblot bands against T. asiatica infected sera. Antigens of adult Taenia solium also revealed 99-97, 68-66, and 46 kDa bands against T. asiatica infected sera. The immunoblot band of 21.5 kDa exhibited specificity to T. asiatica.

• Parasites, Hosts and Diseases
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• 제51권1호
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• pp.51-54
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• 2013

Not only Taenia solium and Taenia saginata, but also Taenia asiatica infects humans. The last species is not included in the evaluation of the specificity of the immunodiagnostic techniques for taeniasis/cysticercosis. There is currently no specific immunodiagnostic method for T. asiatica available. Therefore, due to the fact that molecular techniques (the only tool to distinguish the 3 Taenia species) are normally not employed in routine diagnostic methods, the 2 questions concerning T. asiatica (its definite geographic distribution and its ability to cause human cysticercosis), remain open, turning T. asiatica into the most neglected agent of human taeniasis-cysticercosis.

• Parasites, Hosts and Diseases
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• 제55권4호
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• pp.457-460
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• 2017

Previous paleoparasitological studies of Joseon specimens established that the prevalence of Taenia infection was not much different from that of the early 20th century Korean population. As many of taeniases originally diagnosed as Taenia saginata in South Korea were revealed to be actually Taenia asiatica, which share a common intermediate host with T. solium (the pig), Joseon people must have ingested raw pork frequently. However, the current examination of extant Joseon documents revealed that the population ate significant amounts of beef even if the beef ban was enforced; and pork was not consumed as much as we thought. Considering the meat consumption pattern at that time, Joseon people should have been infected by T. saginata more frequently than T. asiatica. This may suggest a low prevalence of T. saginata metacestodes in cattle compared to that of T. asiatica metacestodes in pigs, possibly due to the traditional way of rearing pigs (using human feces). This letter gives us a chance to reconsider the existing preconception about parasitic infections in Korean history though we are still hard to accurately estimate the historical patterns of taeniases at this stage.

• Parasites, Hosts and Diseases
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• 제51권1호
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• pp.55-59
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• 2013

Twelve 924 bp cytochrome c oxidase subunit 1 (cox1) mitochondrial DNA sequences from Taenia asiatica isolates from Thailand were aligned and compared with multiple sequence isolates from Thailand and 6 other countries from the GenBank database. The genetic divergence of T. asiatica was also compared with Taenia saginata database sequences from 6 different countries in Asia, including Thailand, and 3 countries from other continents. The results showed that there were minor genetic variations within T. asiatica species, while high intraspecies variation was found in T. saginata. There were only 2 haplotypes and 1 polymorphic site found in T. asiatica, but 8 haplotypes and 9 polymorphic sites in T.saginata. Haplotype diversity was very low, 0.067, in T. asiatica and high, 0.700, in T. saginata. The very low genetic diversity suggested that T. asiatica may be at a risk due to the loss of potential adaptive alleles, resulting in reduced viability and decreased responses to environmental changes, which may endanger the species.

• Parasites, Hosts and Diseases
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• 제51권1호
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• pp.9-17
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• 2013

History and current status of human taeniasis in the Republic of Korea, due to Taenia solium, Taenia asiatica, and Taenia saginata, are briefly reviewed. Until the 1980s, human taeniasis had been quite common in various localities of Korea. A study from 1924 reported 12.0% egg prevalence in fecal examinations. Thereafter, the prevalence of Taenia spp. ranged from 3% to 14% depending on the time and locality. Jeju-do, where pigs were reared in a conventional way, was the highest endemic area of taeniasis. An analysis of internal transcribed spacer 2 and mitochondrial cytochrome c oxidase 1 genes of 68 taeniasis cases reported from 1935 to 2005 in Korea by a research group revealed the relative occurrence of the 3 Taenia spp. as follows: T. solium (4.4%), T. asiatica (75.0%), and T. saginata (20.6%). However, national surveys on intestinal helminths conducted every 5 years on randomly selected people revealed that the Taenia egg prevalence dropped from 1.9% in 1971 to 0.02% in 1997 and finally to 0.0% in 2004. With the exception of 3 egg-positive cases reported in 2008 and 2 worm-proven cases in 2011, no more cases have been officially recorded. Based on these surveys and also on other literature, it can be concluded that taeniasis has virtually disappeared from Korea, although a few sporadic cases may remain hidden. Human cysticercosis is also expected to disappear within a couple of decades in Korea.

• Parasites, Hosts and Diseases
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• 제39권4호
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• pp.267-283
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• 2001

In endemic areas of Taenia tapeworms in Korea, most of the reports showed that T. saginata was dominant over T. solium, but eating pigs is the dominant habit over eating cattle. Why do they have more T saginata despite lower consumption of beef This problem actually has long been recognized but until recently there has been no intensive trial to give a scientific explanation on this epidemiological enigma. By summing up the data published between the years 1963 and 1999, the ratio of armed versus unarmed tapeworms in humans was estimated at approximately 1 :5. The ratio of pig-eaters versus cattle-eaters, however, was approximately 5: 1. This inconsistency could be explained with the recently described T. asiatica, which infects humans through the eating of pig's viscera. We re-evaluate the importance of the consumption of visceral organ of pigs, leading us to an improved epidemiological understanding of the T. asiatica infection together with co-existing T. saginata and T. solium in Korea.

• Parasites, Hosts and Diseases
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• 제51권1호
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• pp.43-49
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• 2013

Three species of tapeworms infect humans in their adult stage (Taenia solium, Taenia saginata and Taenia asiatica). The 3 are flat, opaque white or yellowish, and exceptional long segmented parasites, measuring 1 to 12 m in their adult stage. In this review, the development of the knowledge regarding the first species, mainly focused on understanding how the larval stage or cysticercus is transmitted to humans, is described. The second species is a cosmopolitan parasite that only causes taeniosis and not cysticercosis; therefore, it will not be included. Information on the third species, which is presently being produced, since this species was recognized as such only at the end of the 20th century, will be discussed at the end of this review.