Expression of cysteine aspartyl proteinase 3 from liver tissues of the porkets experimentally infected by Taenia asiatica / 中国人兽共患病学报

In order to provide substantial scientific information for exploring the mechanism of porcine liver injury caused by Taenia asiatica (T.asiatica),the expression of Cysteine aspartyl proteinase 3 (Caspase-3) from liver tissues of porkets that were experimentally infected by T.asiatica was examined.The T.asiatica adults were collected from the taeniasis patients in Duyun,Guizhou Province and identified biologically.The eggs were harvested from gravid proglottids and prepared by repeated washing and centrifugation.Twelve 20-days old Yorkshire and Seghers hybrid porkets were randomly divided into experimental and control groups as six pigs per group.The experimental group was orally administrated with 1.5 × 106 eggs per porket at day 0 post-infection.The porkets of both groups were sacrificed on the day 15 and day 75 post-infection (three pigs per time point) respectively,and liver samples were collected for further experiments.Quantitative real-time polymerase chain reaction method was employed to detect the mRNA levels of Caspase-3,and western blotting and immunohistochemistry methods were performed to detect the level of Caspase-3 expression in both groups.At the day 15 post-infection,the mRNA level and expression level of Caspase-3 of the experimental group were significantly decreased,comparison with the control group (P =0.011,P=0.008 and P=0.004 respectively).It was positive with Caspase-3 when yellow or brown signal appeared in the cytoplasm of liver cells by immunohistochemistry.However,at the day 75 post-infection,the mRNA level and expression level of Caspase-3 of the experimental group were dramatically similar to the control group.Furthermore,in the experimental group,the mRNA level and expression level of Caspase-3 were significantly increased at day 75 post-infection than day 15 post-infection (P--0.018,P=0.003 and P=0.002 respectively).These results suggested that Caspase-3 might be involved into the regulation of the damage of porcine liver induced by T.asiatica challenge at the early infection stage and have on effect to the hepatic injury because of the dramatic recovery of Caspase-3 at the consequent infection stage.

A Case of Taenia asiatica Infection Diagnosed by Colonoscopy

A case of Taenia asiatica infection detected by small bowel series and colonoscopy is described. The patient was a 42-year-old Korean man accompanied by discharge of movable proglottids via anus. He used to eat raw pig liver but seldom ate beef. Small bowel series radiologic examinations showed flat tape-like filling defects on the ileum. By colonoscopy, a moving flat tapeworm was observed from the terminal ileum to the ascending colon. The tapeworm was identified as T. asiatica by mitochondrial DNA sequencing. The patient was prescribed with a single oral dose (16 mg/kg) of praziquantel.

Historical Details about the Meat Consumption and Taeniases in Joseon Period of Korea

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.

Infection of Taenia asiatica in a Bai Person in Dali, China

We report here a human case of Taenia asiatica infection which was confirmed by genetic analyses in Dali, China. A patient was found to have symptoms of taeniasis with discharge of tapeworm proglottids. By sequencing of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene, we observed nucleotide sequence identity of 99% with T. asiatica and 96% with T. saginata. Using the cytochrome b (cytb) gene, 99% identity with T. asiatica and 96% identity with T. saginata were found. Our findings suggest that taeniasis of people in Dali, China may be mainly caused by T. asiatica.

Taenia asiatica: the Most Neglected Human Taenia and the Possibility of Cysticercosis

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.

Genetic Diversity of Taenia asiatica from Thailand and Other Geographical Locations as Revealed by Cytochrome c Oxidase Subunit 1 Sequences

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.

Molecular Approaches to Taenia asiatica

Taenia solium, T. saginata, and T. asiatica are taeniid tapeworms that cause taeniasis in humans and cysticercosis in intermediate host animals. Taeniases remain an important public health concerns in the world. Molecular diagnostic methods using PCR assays have been developed for rapid and accurate detection of human infecting taeniid tapeworms, including the use of sequence-specific DNA probes, PCR-RFLP, and multiplex PCR. More recently, DNA diagnosis using PCR based on histopathological specimens such as 10% formalin-fixed paraffin-embedded and stained sections mounted on slides has been applied to cestode infections. The mitochondrial gene sequence is believed to be a very useful molecular marker for not only studying evolutionary relationships among distantly related taxa, but also for investigating the phylo-biogeography of closely related species. The complete sequence of the human Taenia tapeworms mitochondrial genomes were determined, and its organization and structure were compared to other human-tropic Taenia tapeworms for which complete mitochondrial sequence data were available. The multiplex PCR assay with the Ta4978F, Ts5058F, Tso7421F, and Rev7915 primers will be useful for differential diagnosis, molecular characterization, and epidemiological surveys of human Taenia tapeworms.

Human Taeniasis in the Republic of Korea: Hidden or Gone?

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.

Current Status and Perspectives of Cysticercosis and Taeniasis in Japan

This mini-review describes recent epidemiological trends in cysticercosis and taeniasis in Japan. Some of the topics discussed herein were presented at the first symposium on "Current perspectives of Taenia asiatica researches", that was held in Osong in Chungbuk Province, South Korea, in October 2011 and organized by Prof. K. S. Eom, Chungbuk National University School of Medicine. To better understand the trends in the occurrence of cysticercosis and taeniasis in Japan, clinical cases reported in 2005 have been updated. In addition, the current status of Taenia asiatica infections successively occurring in Japan since 2010 is also discussed.

Historical Overview of Taenia asiatica in Taiwan

An overview of the epidemiological, biological, and clinical studies of Taenia and taeniasis in Taiwan for the past century is presented. The phenomenal observations that led to the discovery of Taenia asiatica as a new species, which differ from Taenia solium and Taenia saginata, are described. Parasitological surveys of the aborigines in Taiwan revealed a high prevalence of taeniasis, which might be due to the culture of eating raw liver of hunted wild boars. Chemotherapeutic deworming trials involving many patients with taeniasis were discussed. Praziquantel was found to be very effective, but sometimes complete worms could not be recovered from the feces after treatment, probably due to the dissolution of the proglottids. Atabrine, despite some side effects, can still be used, in properly controlled dosages, as the drug of choice for human T. asiatica infection if we need to recover the expelled worms for morphological examinations. Research results on the infection of T. asiatica eggs from Taiwan aborigines in experimental animals were also noted. Since the pig serve as the natural intermediate host of T. asiatica and the predilection site is the liver, a differential comparison of other parasitic pathogens that might cause apparently similar lesions is also presented.

Current Status of Taeniasis in Thailand

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.

State of the Art of Taenia solium as Compared to Taenia asiatica

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.

Immunoblot Patterns of Taenia asiatica Taeniasis

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 97 kDa and 21.5 kDa 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.

Geographical Distribution of Taenia asiatica and Related Species

Geographical information of Taenia asiatica is reviewed together with that of T. solium and T. saginata. Current distribution of T. asiatica was found to be mostly from Asian countries: the Republic of Korea, China, Taiwan, Indonesia, and Thailand. Molecular genotypic techniques have found out more countries with T. asiatica from Japan, the Philippines, and Vietnam. Specimens used in this paper were collected from around the world and mostly during international collaboration projects of Korean foundations for parasite control activities (1995-2009) in developing countries.

Current Situation of Taeniasis and Cysticercosis in Indonesia

Three human taeniid species, <I>Taenia solium, Taenia saginata</I> and <I>Taenia asiatica</I> are distributed in Indonesia. A field survey conducted in Bali from 2002 to 2006 showed that the prevalence of taeniasis was highly variable among four districts (1.1-27.5%), and only two cysticercosis cases due to <I>T. solium</I> infection were detected. All tapeworms (n = 66) expelled from 66 tapeworm carriers were confirmed to be <I>T. saginata</I> by mitochondrial DNA analysis. A total prevalence of 13.0% (19⁄146) for <I>T. solium</I> taeniasis was found in Jayawijaya District, Papua (Irian Jaya). It included 14 of 88 (15.9%) in 1999 and 5 of 58 (8.6%) in 2001, while the seroprevalence of cysticercosis in humans by sub-district in Papua ranged from 0.0% in a non-endemic area to 48.5% in an endemic area from 1996 to 2005. The seroprevalence of cysticercosis in pigs and dogs in Jayawijaya ranged from 8.5% to 70.4% (1998-1999) and 4.9% to 33.3% (2000-2002), respectively. A 2003-2006 survey of 371 local people in Samosir island, north Sumatra revealed 6 of 240 (2.5%) to be infected with <I>T. asiatica</I>; 2 of 58 (3.4%) and 4 of 182 (2.2%) cases were detected in 2003 and 2005, respectively. This brief review summarizes the present situation of taeniasis and cysticercosis, the distribution of three human taeniid species, and the risk factors⁄transmission aspects of these tapeworm infections in Bali, Papua, and north Sumatra regions of Indonesia.

Molecular identification of Taenia asiatica isolated from a patient in Ha Tay province of Vietnam

Sample of tapeworm was isolated from 1 patient in Ha Tay province. It was amplified by polymerase chain reaction (PCR), purified, cloned and sequenced. The nucleotide sequence was comparatively aligned with the known corresponding sequences of Taenia asiatica (Taiwanese); T. saginata (Chinese) and T. solium (Chinese and Vietnamese) and used for establishing a phylogenetic relationship for analysis of identification, using special programs. Molecular-based analysis revealed that the Taenia sp from this patient is identified as Taenia asiatica. Absolute nucleotide similarity (100%) between Taenia asiatica in Ha Tay, Vietnam and Taenia asiatica in Taiwan; the grouping together with T. asiatica (Taiwan) confirmed the sample obtained from Ha Tay is closely related to the Taiwanese T. asiatica

Research Progress on Molecular Identification and Biologic Behavior of Taenia saginata in Western China / 中国寄生虫学与寄生虫病杂志

This article reviews the epidemiological investigation of taeniasis saginata in 10 counties of 7 provinces/ autonomous regions in western China.The morphological observation of adult worms,molecular identification of 10 isolates of the worms,experimental infection on pigs and cattle with Taenia saginata and T.asiatica,observation on development and bio-logy behavior of cysticercus,and pathological changes in the intermediate host pig and cattle revealed that T.asiatica is a new species,instead of a subspecies of T.saginata.