Showing papers on "Bulinus truncatus published in 2007"
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TL;DR: It is demonstrated that C. limnaei, symbiotically associated with snail vector of parasitic diseases, may have important implications with respect to biological control and/or changes in the epizootiology of native parasites in the study area.
Abstract: The objectives of this work were to study (1) the population dynamics of Chaetogaster limnaei in the field populations of freshwater snails and the implications for the species as a potential regulator of the trematode larvae community and (2) prevalence and intensity of C. limnaei in relation to host species, host size, and season. This study was conducted at Al-Salam Canal and Al-Abtal village (new cultivated area in north Sinai). The samples were collected from March 2004 to February 2005. The natural infection rate by trematodes and C. limnaei was assessed monthly. Thirteen species of snails were examined for C. limnaei infection, five species were found infected. There were positive correlations between host size and both combined prevalence and mean intensity in all hosts. The data demonstrated that prevalence in Bulinus truncatus was higher when compared with other hosts. Bellamya unicolor has higher mean intensity when compared with other host species. A significant difference was found between host species and both prevalence and intensity. There were spatial and temporal variations in prevalence and mean intensity in most hosts, and the data suggest some seasonality. A negative correlation was found between prevalence of C. limnaei and trematode infection. C. limnaei did not co-occur with trematode larvae in infected hosts indicating that the oligochaete may protect the hosts from trematode infection. B. unicolor was recorded for the first time as a host for C. limnaei. C. limnaei may be a potential regulator of the trematode community in freshwater snails. In conclusion, this study demonstrated that C. limnaei, symbiotically associated with snail vector of parasitic diseases, may have important implications with respect to biological control and/or changes in the epizootiology of native parasites in the study area.
41 citations
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TL;DR: Taxonomic sampling is increased through addition of several taxa, including B. nyassanus and B. succinoides both endemic to Lake Malawi, which appear basal within the B. truncatus/tropicus species complex which provides an interesting evolutionary insight into its origins.
Abstract: Freshwater snails of the genus Bulinus, subfamily Bulininae, are widespread in Africa and the Middle East. Several species are intermediate hosts for schistosomes, mammalian blood flukes that cause schistosomiasis. The genus is split into four species groups and without recourse to further molecular DNA studies, phylogenetic relationships within and between species-groups remain obscure. For example, the Bulinus truncatus/tropicus species complex, which cannot be adequately defined with morphological characters, appears to be monophyletic but increased taxon sampling is warranted for confirmation when this group appears to contain species with limited sequence divergence in either mitochondrial 16S rRNA or Cytochome Oxidase subunit I (COI) loci. In the present study, taxonomic sampling is increased through addition of several taxa, including B. nyassanus and B. succinoides both endemic to Lake Malawi. From DNA analyses, these two species appear basal within the B. truncatus/tropicus species complex which provides an interesting evolutionary insight into its origins. The relationship of the B. truncatus/tropicus species complex with the three other groups, however, is more problematic as incongruence between loci and computational methodologies exist. This phenomenon is likely due to mutational saturation of the COI as evidenced by the transition : transversion ratio which also results in placement of the discoidal Indoplanorbis exustus, a member of the Bulininae, within the ingroup. To resolve these more basal incongruencies between species groups inspection of more evolutionary conserved molecular loci is needed, for example, the nuclear histone H3 gene, and 18S and 28S rDNA.
Louise V. Gersdorff Jorgensen, Thomas K. Kristensen and Henry Madsen, The Mandahl-Barth Research Centre for Biodiversity and Health, DBL — Centre for Health Research and Development, Department of Veterinary Pathobiology, Faculty of Life Sciences, University of Copenhagen, Jaegersborg Alle 1D, DK-2920 Charlottenlund, Denmark. E-mails: lgj@life.ku.dk, tkk@life.ku.dk, hmad@life.ku.dk
J. Russell Stothard, Biomedical Parasitology Division, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK. E-mail: R.Stothard@nhm.ac.uk
24 citations
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TL;DR: Calcium content was significantly higher in the shells than in the soft parts of the snails, regardless infected or uninfected, and the hypothesis of hypercalcification in shells of infected snails was discussed.
Abstract: Flame atomic absorption spectrometry was performed to determine the alteration of calcium concentration in the soft parts and shells of Biomphalaria alexandrina and Bulinus truncatus due to the infection with Schistosoma mansoni and S. haematobium, respectively. The results showed significant lowering in the calcium content of the shells of cercariae shedding B. alexandrina and B. truncatus relative to the calcium content in the shells of uninfected ones. In contrast, the calcium content in the soft parts of cercariae shedding snails was higher than in the soft parts of uninfected snails; the differences were statistically significant. Generally, calcium content was significantly higher in the shells than in the soft parts of the snails, regardless infected or uninfected. The results obtained and the hypothesis of hypercalcification in shells of infected snails were discussed.
19 citations
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TL;DR: These findings may be used to detect the presence of either of both intermediate hosts in numerous spring heads which are present on the western slope of the Anti Atlas mountains and the corresponding valleys, via the study of 12 physicochemical parameters in running water.
Abstract: Since Bulinus truncatus and Planorbarius metidjensis are the intermediate hosts of Schistosoma haematobium in southwestern Morocco, five rivers were investigated to identify sites colonized by either of both species and determine the characteristics of their habitats via the study of 12 physicochemical parameters in running water. P. metidjensis was observed in the upper valleys of three rivers, whereas B. truncatus was found in sites of lower altitude. A component analysis demonstrated that altitude (from 4 to 1,380 m), water pH (from 5.9 to 9.2), and electric conductivity (from 120 to 6,020 microS/cm) were the main descriptors of environment. A multiple correspondence analysis showed that P. metidjensis was associated to Ancylus fluviatilis, high altitude, and possibly low electric conductivity. B. truncatus was associated to Melanoides tuberculata and was found in lower altitude sites with medium electric conductivity in water. Using logistic regressions, the main characteristics were altitude and dissolved oxygen for B. truncatus, and chlorides and CaCO3 for P. metidjensis. As the habitats of both S. haematobium intermediate hosts differed from each other by altitude and the frequency of snails, which cohabited with them, these findings may be used to detect the presence of either of both intermediate hosts in numerous spring heads which are present on the western slope of the Anti Atlas mountains and the corresponding valleys.
7 citations
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TL;DR: Since Planorbarius metidjensis was recently found to be an experimental intermediate host of Schistosoma haematobium in the South-West of Morocco, a study on planorbid and B. truncatus was carried out from 1997 to 2005, revealing the absence of natural infections with S. haem atobium.
Abstract: Since Planorbarius metidjensis was recently found to be an experimental intermediate host of Schistosoma haematobium in the South-West of Morocco, a study on planorbid and B. truncatus was carried out from 1997 to 2005. Eleven planorbid populations were identified in 1997 in the Agadir province, all living at high altitude (from 340 to 1380 m). In contrast, most of the seven bulinid populations inhabited low-lying zones. Three annual generations of P. metidjensis (April-July June-September, and August-March) were noted in two populations (living in perennial bodies of water) in Imouzzer so that juvenile snails were present throughout the year. The dissection of numerous snails collected from these 18 populations between 1999 and 2005 revealed the absence of natural infections with S. haematobium. As most cases of human bilharziosis detected in the Agadir region between 1993 and 1997 are located in highlands, P. metidjensis might be the principal intermediate host of S. haematobium in districts at 500 m above sea level.
6 citations
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TL;DR: The immunoperoxidase technique proved to be an effective indicator for the schistosome-antigen in the snails by detecting positive reaction in B. alexandrina and B. truncates.
Abstract: The reaction of the haemolymph and the tissue of infected intermediate hosts, Biomphalaria alexandrina and Bulinus truncatus to Schistosoma mansoni and S. haematobium antigens were investigated using the indirect immunoperoxidase technique. A new technique, Agarose cell block was used in collection of haemolymph which helped in collecting plenty of well formed cells in comparison to the ordinary one using the cytospin. Collected haemolymph and prepared tissues of uninfected and infected B. alexandria and B. truncatus were fixed and then reacted with anti-S. mansoni and anti-S. haematobium IgG polyclonal antibodies. The haemolymph and tissue of infected B. alexandrina and B. truncatus gave a positive peroxidase reaction represented by a brown colour. In haemolymph, the positive peroxidase reaction was detected mainly in the cytoplasm of the amoebocytes. In the tissue, it was detected in epithelial cells lining the tubules, male cells in the lumen of the tubules and in female oogonia cells along the periphery of the tubules. The similarity in the strength and distribution of positive reaction in B. alexandrina and B. truncates was observed as compared to control. Thus, the immunoperoxidase technique proved to be an effective indicator for the schistosome-antigen in the snails.
2 citations
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TL;DR: The lack of deep molecular divergences between populations of Bulinus sp.