Article

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

Laboratory of Parasitology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, 060-0818, Japan.
Parasitology Research (Impact Factor: 2.85). 06/2005; 96(2):95-101. DOI: 10.1007/s00436-005-1328-4
Source: PubMed

ABSTRACT Development of Taenia saginata asiatica metacestodes in SCID mice, and its infectivity in humans, golden hamsters, and Mongolian gerbils as alternative definitive hosts, were investigated. Cysticerci were recovered from SCID mice that were subcutaneously injected with hatched oncospheres of T. s. asiatica. The morphological changes of metacestodes were observed. The recovered cysticerci were fed to gerbils, hamsters and humans, to check for their infectivity. Tapeworms were recovered from gerbils and hamsters fed with 20 to 45 week-old cysticerci, and proglottids excretions 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.

0 Bookmarks
 · 
48 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: It is well understood that sociocultural practices strongly influence Taenia solium transmission; however, the extent to which interspecific parasite competition moderates Taenia transmission has yet to be determined. This is certainly the case in Southeast Asia where T. solium faces competition in both the definitive host (people) and the intermediate host (pigs). In people, adult worms of T. solium, T. saginata and T. asiatica compete through density-dependent crowding mechanisms. In pigs, metacestodes of T. solium, T. hydatigena and T. asiatica compete through density-dependent immune-mediated interactions. Here, we describe the biological and epidemiological implications of Taenia competition and propose that interspecific competition has a moderating effect on the transmission dynamics of T. solium in the region. Furthermore, we argue that this competitive ecological scenario should be considered in future research and surveillance activities examining T. solium cysticercosis and taeniasis in Southeast Asia.
    Trends in Parasitology 10/2009; 25(9):398-403. · 5.51 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Humans are definitive hosts of two well-known species of the Taenia genus, Taenia solium (the pig tapeworm) and Taenia saginata (the cattle tapeworm). In the 1990s, a third species, Taenia asiatica, was discovered, sharing features with the other two since the adult morphology is similar to that of T. saginata, but its life cycle is like that of T. solium. Human taeniasis usually is asymptomatic or displays mild symptoms, and only T. solium can cause other sometimes serious disorders when humans accidentally ingest the eggs and develop the larval stage in different organs (cysticercosis). In this review, we expose what we currently know (lights) and what we do not yet know (shadows) about the life cycle and pathogenicity of T. asiatica. Concerning its life cycle, the main uncertainty is whether humans can act as intermediate hosts of this species. We also suggest that due to its small size and location in pigs, the cysticerci probably escape veterinary inspection becoming a silent parasite. Concerning pathogenicity, it is still not known if T. asiatica can cause human liver cysticercosis, taking into account its principal hepatic tropism in pigs. To answer all these questions it would be essential to perform sensitive as well as specific diagnostic techniques for T. asiatica in humans and pigs. Currently, only molecular methods are able to determine the Taenia species, since morphology and immunology are useless, but unfortunately although largely used in research those methods are not employed in routine diagnosis.
    Tropical parasitology. 07/2013; 3(2):114-9.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: An overview of the epidemiological, biological, and clinical studies of and taeniasis in Taiwan for the past century is presented. The phenomenal observations that led to the discovery of as a new species, which differ from and , 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 infection if we need to recover the expelled worms for morphological examinations. Research results on the infection of eggs from Taiwan aborigines in experimental animals were also noted. Since the pig serve as the natural intermediate host of and the predilection site is the liver, a differential comparison of other parasitic pathogens that might cause apparently similar lesions is also presented.
    The Korean Journal of Parasitology 02/2013; 51(1):31-6. · 0.88 Impact Factor

Full-text

View
0 Downloads
Available from