Taenia

About: Taenia is a research topic. Over the lifetime, 1293 publications have been published within this topic receiving 24256 citations.

Identification of taeniid eggs in the faeces from carnivores based on multiplex PCR using targets in mitochondrial DNA.

Abstract: A multiplex polymerase chain reaction (PCR) was evaluated for the identification of morphologically indistinguishable eggs of the taeniid tapeworms from carnivores using primers targeting mitochondrial genes. The primers for Echinococcus multilocularis (amplicon size 395 bp) were species-specific as assessed by in silica analysis and in the PCR using well-defined control samples. The design of primers that specifically amplify DNA from E. granulosus or Taenia spp. was not possible. The primers designed for E. granulosus also amplified DNA (117 bp) from E. vogeli, and those designed for Taenia spp. amplified products (267 bp) from species of Mesocestoides, Dipylidium and Diphyllobothrium. Nevertheless, as our diagnostic approach includes the concentration of taeniid eggs by sequential sieving and flotation, followed by their morphological detection, this non-specificity has limited practical importance. Sequence analysis of the corresponding amplicon can identify most of the described E. granulosus genotypes. Taenia spp. can be identified by direct sequencing of the 267 bp amplicon, or, for most species, by restriction fragment length polymorphism (RFLP) analysis. The multiplex PCR was readily able to detect 1 egg (estimated to contain 7000 targets, as determined by quantitative PCR). Having been validated using a panel of well-defined samples from carnivores with known infection status, this approach proved to be useful for the identification of taeniid eggs from both individual animals and for epidemiological studies.

Successful treatment of Diphyllobothrium latum and Taenia saginata infection by intraduodenal 'Gastrografin' injection

Abstract: Tapeworm infections are very difficult to cure completely. Thirteen patients with tapeworm infection, seven with Diphyllobothrium latum and six with Taenia saginata, were treated by the introduction of a radio-opaque contrast medium, 'Gastrografin', into the duodenum through a duodenal tube. The whole tapeworm with the scolex was expelled unfragmented within 1 h in eleven cases. One patient expelled a tapeworm 3 days after treatment; the peristalsis of his intestine had been severely disturbed after an attack of cerebral apoplexy. The tapeworm could not be expelled by the remaining patient, probably because she had severe intestinal adhesion. The injection of gastrografin allowed clear visualisation of the tapeworm, the diagnosis of the infection could be confirmed, and the descent of the tapeworm could be observed serially. This treatment had no serious adverse effects in any of out patients.

Genetic Characterization of the Asian Taenia, a Newly Described Taeniid Cestode of Humans

Abstract: Recent studies on the epidemiologic pattern of taeniasis in Southeast Asia have indicated the existence of a third form of human Taenia, distinguishable from Taenia saginata and T. solium. Originally termed Taiwan Taenia, and first described in Taiwanese aboriginals, this newly recognized taeniid is now generally referred to as Asian Taenia since it has since been recorded in a number of other Asian countries. Here we have used a genetic yardstick approach to determine whether the Asian Taenia should most appropriately be considered as a new, distinct species or as a subspecies, strain, or variant of T. saginata, which previous studies have shown it closely resembles. Sequence variation in the 28S rRNA and mitochondrial cytochrome c oxidase I (COI) genes of a range of taeniid cestodes and the COI and rDNA internal transcribed spacer I polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) pattern differences in the Asian Taenia, T. saginata, and T. solium were used as markers of genetic identity. The PCR-RFLP approaches proved useful for rapid and unambiguous discrimination of Asian Taenia from the other two human species, whereas the mitochondrial and nuclear sequence comparisons indicate that the Asian Taenia is much more closely related to T. saginata than recognized taeniid species are to each other. The results support earlier conclusions that the Asian Taenia is a genetically distinct entity but is closely related to T. saginata, and suggest that its taxonomic classification as a subspecies or strain of T. saginata is more appropriate than formal designation as a new species. The very close relationship between Asian Taenia and T. saginata has public health implications in that the Asian form is unlikely to be an important cause of human cysticercosis because T. saginata cysticercosis, if it occurs at all in humans, is an extremely rare phenomenon.

DNA differential diagnosis of taeniasis and cysticercosis by multiplex PCR

Abstract: Multiplex PCR was established for differential diagnosis of taeniasis and cysticercosis, including their causative agents. For identification of the parasites, multiplex PCR with cytochrome c oxidase subunit 1 gene yielded evident differential products unique for Taenia saginata and Taenia asiatica and for American/African and Asian genotypes of Taenia solium with molecular sizes of 827, 269, 720, and 984 bp, respectively. In the PCR-based detection of tapeworm carriers using fecal samples, the diagnostic markers were detected from 7 of 14 and 4 of 9 T. solium carriers from Guatemala and Indonesia, respectively. Test sensitivity may have been reduced by the length of time (up to 12 years) that samples were stored and/or small sample volumes (ca. 30 to 50 mg). However, the diagnostic markers were detected by nested PCR in five worm carriers from Guatemalan cases that were found to be negative by multiplex PCR. It was noteworthy that a 720 bp-diagnostic marker was detected from a T. solium carrier who was egg-free, implying that it is possible to detect worm carriers and treat before mature gravid proglottids are discharged. In contrast to T. solium carriers, 827-bp markers were detected by multiplex PCR in all T. saginata carriers. The application of the multiplex PCR would be useful not only for surveillance of taeniasis and cysticercosis control but also for the molecular epidemiological survey of these cestode infections.