دورية أكاديمية
Recent studies on Schistosoma intercalatum: taxonomic status, puzzling distribution and transmission foci revisited
| العنوان: | Recent studies on Schistosoma intercalatum: taxonomic status, puzzling distribution and transmission foci revisited |
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| المؤلفون: | Joseph Jourdane, Vaughan R Southgate, Jean René Pagès, Patrick Durand, Louis Albert Tchuem Tchuenté |
| المصدر: | Memorias do Instituto Oswaldo Cruz, Vol 96, Pp 45-48 (2001) |
| بيانات النشر: | Fundação Oswaldo Cruz (FIOCRUZ), 2001. |
| سنة النشر: | 2001 |
| المجموعة: | LCC:Microbiology LCC:Infectious and parasitic diseases |
| مصطلحات موضوعية: | Schistosoma intercalatum, Schistosoma mansoni, Schistosoma haematobium, taxonomic status, sexual interactions, epidemiology, transmission foci, Microbiology, QR1-502, Infectious and parasitic diseases, RC109-216 |
| الوصف: | Schistosoma intercalatum, which causes human rectal schistosomiasis in Africa, still presents a great interest for its imprecise taxonomic status and its puzzling distribution in Africa. Two geographically isolated strains of S. intercalatum are recognized, the Lower Guinea strain and the Congo strain, which differ from each other in a number of morphological, biological and biochemical characteristics. Recent molecular data using RAPD markers indicate high divergence between the two strains, with values of Nei and Li's similarity indice allowing recognition of two genetically distinct taxa: experiments on pre- and post-isolating mechanisms are in progress in order to re-evaluate the taxonomic status of this polytypic species. With regard to its geographical distribution, S. intercalatum is characterized by the existence of two stable endemic areas (localized in Lower Guinea and North East of Democratic Republic of Congo) which correspond to the historical areas of species discovery, and the emergence during the last 15 years of new foci of the Lower Guinea strain outside previously known endemic areas. The absence of local adaptation of the Lower Guinea strain to its intermediate host, supported by experimental studies, may help to facilitate the spread of this strain. Nevertheless, the present restricted distribution of this species remains puzzling, because its potential snail hosts (bulinids) are widely distributed throughout much of Africa. Recent experimental and epidemiological studies suggest that interspecific sexual interactions between human schistosomes could have a role in limiting the distribution of S. intercalatum: the competitive sexual processes acting among human schistosomes show that S. haematobium and S. mansoni are always competitively dominant over S. intercalatum. These epidemiological observations lead the authors to distinguish three kinds of transmission foci for S. intercalatum. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 0074-0276 1678-8060 |
| Relation: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762001000900006; https://doaj.org/toc/0074-0276; https://doaj.org/toc/1678-8060 |
| DOI: | 10.1590/S0074-02762001000900006 |
| URL الوصول: | https://doaj.org/article/5cc3417f00b34ca2accf5f699b52b234 |
| رقم الأكسشن: | edsdoj.5cc3417f00b34ca2accf5f699b52b234 |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 00740276 16788060 |
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| DOI: | 10.1590/S0074-02762001000900006 |