Taiwan Taenia and Taeniasis

Fan, P. C.

doi:10.1016/0169-4758(88)90204-9

Cited by 86 publications

(70 citation statements)

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“…Field-based investigations by Fan [51,52] established the existence of an apparently unique Taenia circulating among humans and swine in Taiwan, and adjacent areas of SE Asia. Initial studies were based on comparative morphology, epidemiology and elucidation of the life cycle for what was designated as ''Taiwan'' or ''Asian'' Taenia, a taxon of uncertain affinities that was not formally named in these early reports; also tentatively referred to as T. saginata taiwanensis [53], Recognizing the unique biology for this taeniid (circulating in pig intermediate hosts with cysticerci in the liver and visceral organs), distinct structural characters relative to T. saginata and a broader distribution in Asia led Eom and Rim [22] to formally name, describe and provide a differential diagnosis for T. asiatica.…”

Section: Taenia Asiatica a Valid Speciesmentioning

confidence: 99%

Phylogeny of Taenia: Species definitions and origins of human parasites

Hoberg¹

2006

Parasitology International

127

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Phylogeny is fundamental as it constrains explanations about history and forms our foundation for recognizing and diagnosing species. In the absence of such a framework taxonomists historically relied on intuitive processes, personal judgment and authority, often embracing a typological view of species that disregarded otherwise unequivocal historical and biological criteria. Species of Taenia are among the most characteristic tapeworms infecting carnivores and humans as definitive hosts and indeed Taeniidae is unique among the Eucestoda in requiring 2 obligate mammalian hosts for transmission; a high percentage (> 80%) of life cycles have been completely elucidated among the approximately 45 species and nominal subspecies of Taenia. Until recently there had been no comprehensive attempts at reconstruction of a phylogeny among these important parasites. Such analyses have allowed us to explore the origins and evolution of those independent species of Taenia that occur in humans (T. saginata, T. asiatica, and T. solium) and to understand the ecological and historical processes serving as determinants of biogeography and hostassociation. These studies supported the status of T. asiatica as a valid species and diagnosed a relationship as the sister-species of T. saginata. These conclusions contrasted with a diversity of opinions that would subsume T. asiatica as a subspecies. Recognition of a species constitutes a specific and testable hypothesis, is not an arbitrary decision and is most appropriately assessed in the context of phylogenetic or historical data. Considering macrospecies, a process has been outlined by Brooks and McLennan [Brooks DR, McLennan DA. The nature of diversity: an evolutionary voyage of discovery. University of Chicago Press: Chicago; 2002] as follows: (1) Discovery: a systematist describes the species; (2) Phylogenetic reconstruction; (3) Evaluation I: do sister-species show geographical overlap-are they sympatric or allopatric (use phylogeny + geographical distributions)? (4) Evaluation II: are sister-species reproductively isolated based on information from natural history, ecology and reproductive biology? Species may be viewed in the context of microevolutionary and macroevolutionary processes. For instance, microspecies are defined in ecological time and involve populations and contemporary process that are potentially reversible (reticulate). In contrast, macrospecies as exemplified by T. saginata and T. asiatica are divergent lineages resulting from processes in evolutionary time where an ancestor has undergone a permanent split that is non-reversible (non-reticulate). Applying these criteria in evaluation of T. saginata and T. asiatica, it becomes clear that in evolutionary time these represent historical lineages with independent spatial and temporal trajectories, having separated from a common ancestor near 0.78 to 1.71 MYBP in Africa, or Eurasia. In ecological time, sympatry, reproductive isolation, and differences in life history evident for T. saginata and T. asiatica a...

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Section: Taenia Asiatica a Valid Speciesmentioning

confidence: 99%

Phylogeny of Taenia: Species definitions and origins of human parasites

Hoberg¹

2006

Parasitology International

127

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“…Cysticercosis cases were suspected by questionnaires on the history of epileptic seizures, detection of subcutaneous nodule by palpation and serological examination for T. solium cysticercosis . All tapeworms expelled from tapeworm carriers were confirmed by mtDNA analysis using cytochrome c oxidase subunit I (cox1) gene to differentiate T. solium, T. saginata and T. asiatica (Yamasaki et al, 2004a(Yamasaki et al, , 2004b(Yamasaki et al, , 2004c, since proglottids of T. saginata and T. asiatica are morphologically identical (Fan 1988;Eom and Rim, 1993;Ito et al, 2003; and T. asiatica was also expected to be distributed in Bali (Dharmawan, 1998). Additional data through questionnaires from 106 family heads were also collected in a non-endemic Taenia area (Banjar) in East Denpasar Sub-District (Denpasar District) as a family control for the 106 family heads living in the taeniasis endemic area (Banjar) in Ketewel and Penatih villages.…”

Section: Introductionmentioning

confidence: 99%

High prevalence of Taenia saginata taeniasis and status of Taenia solium cysticercosis in Bali, Indonesia, 2002–2004

Wandra

Sutisna

Dharmawan

et al. 2006

Transactions of the Royal Society of Tropical Medicine and Hygi

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1 SummaryAn epidemiological survey of taeniasis/cysticercosis was carried out in one semi-urban and two urban villages in three districts in Bali, Indonesia in 2002 and. A total of 398 local people from 247 families were diagnosed by anamnesis and clinical examinations, and 60 residents were suspected to be taeniasis carriers. Among 60 suspected carriers, 56 persons expelled a total of 61 taeniid adult worms after praziquantel treatment. From 398 residents, 252 stool samples were available for analysis of taeniid eggs, copro-antigens or copro-DNA for identification of taeniid species, and 311 serum samples were available for detection of antibodies against Taenia solium cysticercosis. Taeniasis prevalences were highly variable among three villages (1.1-27.5%) and only one cysticercosis due to T. solium infection was detected. All expelled tapeworms were confirmed to be Taenia saginata by mitochondrial DNA analysis. There was no Taenia asiatica human case in Bali. Case control analysis of 106 families chosen at random from 179 families in 2004 and another 106 families from non-endemic areas revealed that risk factors of T. saginata taeniasis for families were the level of education (p < 0.01), the consumption of beef lawar (p < 0.01) and the source of lawar (p < 0.01).

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“…Metacestodes of T. s. asiatica had been found to develop to maturity in the liver of experimentally infected pigs, showing hooklets and active movement at 28 DPI (Fan 1988). In SCID mice, T. s. asiatica metacestodes had been reported to develop to cysticerci with a total length (after the evagination) of 16 and 31 mm, and with suckers diameter of 199 and 252 µm at 9 and 25 weeks after subcutaneous inoculation, respectively .…”

Section: Discussionmentioning

confidence: 99%

Development of Taenia saginata asiatica metacestodes in SCID mice and its infectivity in human and alternative definitive hosts

et al. 2005

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Development of Taenia saginata asiatica metacestodes in SCID mice and its infectivity in humans, and in golden hamsters and Mongolian gerbils as alternative definitive hosts, were investigated. Cysticerci were recovered from SCID mice that were subcutaneously injected with hatched eggs of T. s. asiatica. The morphological changes of cysticerci were observed. The recovered cysticerci were by fed to gerbils, hamsters and humans, to check for infectivity.Tapeworms were recovered from gerbils and hamsters that were fed 20 to 45 week-old cysticerci, and proglottids excretion were observed in human volunteers fed with 45 week-old cysticerci.However, no tapeworms were recovered from gerbils fed with 10 week-old cysticerci. Our results suggest that T. s. asiatica oncospheres needed more than 20 weeks to develop to maturity in SCID mice to be infective to both their natural and alternative definitive hosts.

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Taiwan Taenia and Taeniasis

Cited by 86 publications

References 1 publication

Phylogeny of Taenia: Species definitions and origins of human parasites

Phylogeny of Taenia: Species definitions and origins of human parasites

High prevalence of Taenia saginata taeniasis and status of Taenia solium cysticercosis in Bali, Indonesia, 2002–2004

Development of Taenia saginata asiatica metacestodes in SCID mice and its infectivity in human and alternative definitive hosts

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