Showing papers on "Bulinus truncatus published in 2014"

Schistosoma haematobium infections acquired in Corsica, France, August 2013.

Abstract: A 12 year-old boy in Germany developed urinary schistosomiasis in January 2014. He had bathed in rivers in south-eastern Corsica five months earlier. Before this case, human schistomiasis had not been reported on the island, although its vector, the snail Bulinus truncatus, locally transmitted the zoonotic Schistosoma bovis. The boy's father excreted S. haematobium ova that were not viable; the boy's three siblings had a positive serology against schistosomes.

Schistosomiasis haematobium, Corsica, France.

Abstract: To the Editor: In Europe, urinary schistosomiasis (1) has previously been detected only in Portugal, where this focus disappeared during the 1950s (2). However, freshwater snails of the species Bulinus contortus, B. truncatus, and Planorbarius metidjensis, which are recognized intermediate hosts for Schistosoma haematobium trematodes, have been found in Portugal (3), Spain (4), and Corsica (5,6). This finding suggested that autochthonous schistosomiasis could re-emerge in southern Europe if these mollusks become infected. We report a probable focus for transmission of schistosomiasis haematobium in Corsica, France. In March 2014, a 4-year-old girl (index case-patient) from France was referred to the Toulouse University Hospital (Toulouse, France), with gross hematuria. Ultrasonography and cystoscopic examination of the bladder detected a polyp. Examination of the polyp for parasites identified bodies that were consistent with schistosome eggs. Parasitologic examination of urine confirmed schistosomiasis by detecting viable S. haematobium eggs. The parents of the girl (family A) did not report any stay or travel in an area to which urinary schistosomiasis was endemic; they reported summer holidays only in Mallorca in the Balearic Islands (Spain) and Corsica. However, her father reported that since 2012, he had experienced gross hematuria that had been evaluated by standard urologic investigations but not by cystoscopy; no etiology was determined. Parasitologic urinalysis in our hospital department showed numerous viable S. haematobium eggs in the father’s urine. The parents of the index case-patient also reported that an 8-year-old boy in a friend’s family (family B), who shared summer vacations with them had exhibited gross hematuria since February 2013. A third family (family C) was also investigated because they also spent holidays in Corsica with families A and B. Families B and C had also spent a summer in Mallorca, but they denied any contact with freshwater. Of 11 French native-born members of the 3 families, 6 had positive results for S. haematobium by urine examination. All case-patients had specific positive immunodiagnostic results by an ELISA that used S. mansoni extracts and by indirect hemagglutination. In addition, 2 family members who had a negative result by urine examination had a positive serologic result. Spending summer vacations in the same village in Corsica (Sainte-Lucie de Porto-Vecchio), where members of the 3 families had bathed at least once per holiday period in the Cavu River, was the epidemiologically prominent feature that linked these persons. Families A and C were in Sainte-Lucie de Porto-Vecchio in August 2011, and families A, B, and C were in the same location in August 2013. During these investigations, we were contacted by the Department of Tropical Medicine, Dusseldorf University Hospital (Dusseldorf, Germany), because a 10-year-old boy and his father had been given diagnoses of schistosomiasis haematobium on the basis of positive urinalysis results for S. haematobium eggs. Two other members of this family (5 persons) had a positive immunodiagnostic result. Locations of previous vacations for this family outside Germany included Spain (not the Balearic Islands) and Corsica, where they bathed frequently in the Cavu River. These epidemiologic findings provide strong circumstantial evidence supporting the presence of a previously unrecognized focus of urinary schistosomiasis in Corsica. We performed molecular analysis of schistosomal miracidia DNA. The second internal transcribed spacer region of the ribosomal gene complex (7,8) was amplified and sequenced. Viable eggs obtained from the patients in France were those of S. haematobium. Additional molecular investigations are being conducted to assess genetic diversity of this isolate from Corsica and the geographic origin of the introduced parasite. The malacologic situation in Sainte Lucie de Porto-Vecchio was investigated during May 12–19, 2014; three rivers (Figure) were included in the survey. Four sites were sampled in the Cavu River, and B. truncatus snails were found in 3 sites that corresponded to bathing areas (site 1: 41°43′53.57″N, 9°17′36.70″E; site 2: 41°43′22.13″N, 9°17′59.87″E; site 3: 41°42′8.40″N, 9°21′5.82″E). Snails were also found in the nearby Tarcu River (site 5) and Osu River (site 6). These findings confirmed previous data for the presence of B. truncatus snails in Corsica (5,6). Water temperature was recorded at 11:00 am at these 3 sites (range 15°C–16°C). This temperature range is not optimal for the snail intermediate host stage of the parasite life cycle (9,10). Of 148 live snails that were obtained in the Cavu River, none were infected with schistosome cercariae. Figure Corsica, France, showing malacologic survey sampling sites (oval) in 3 rivers (Tarcu, Cavu, and Osu). Bulinus truncatus snails were found at sites 1, 2, 3, 5, and 6. Data from the field survey and epidemiologic information for the cases in France and Germany, indicated transmission of schistosomiasis haematobium in the Cavu River in southeastern Corsica in 2011 and 2013. Additional supportive evidence is the fact that the father of the index case-patient had gross hematuria in 2012 and 2013. Two hypotheses are proposed to account for this situation. The first hypothesis is that the parasite (i.e., schistosome eggs) was transmitted by an infected person into the Cavu River in June or July 2011, when environmental conditions were favorable for snail infection. However, questions arise about survival of infected snails during the winter and their ability to reinfect the area during the following summers in 2012 and 2013. The second hypothesis is that schistosome eggs were spread by infected persons at the beginning of summer and caused a permanent transmission cycle in this focus. This situation would be difficult to control. Additional information should be obtained by a long-term malacologic survey to detect infected mollusks in this region.

Phylogeny of seven Bulinus species originating from endemic areas in three African countries, in relation to the human blood fluke Schistosoma haematobium

Abstract: Snails species belonging to the genus Bulinus (Planorbidae) serve as intermediate host for flukes belonging to the genus Schistosoma (Digenea, Platyhelminthes). Despite its importance in the transmission of these parasites, the evolutionary history of this genus is still obscure. In the present study, we used the partial mitochondrial cytochrome oxidase subunit I (cox1) gene, and the nuclear ribosomal ITS, 18S and 28S genes to investigate the haplotype diversity and phylogeny of seven Bulinus species originating from three endemic countries in Africa (Cameroon, Senegal and Egypt). The cox1 region showed much more variation than the ribosomal markers within Bulinus sequences. High levels of genetic diversity were detected at all loci in the seven studied species, with clear segregation between individuals and appearance of different haplotypes, even within same species from the same locality. Sequences clustered into two lineages; (A) groups Bulinus truncatus, B. tropicus, B. globosus and B. umbilicatus; while (B) groups B. forskalii, B. senegalensis and B. camerunensis. Interesting patterns emerge regarding schistosome susceptibility: Bulinus species with lower genetic diversity are predicted to have higher infection prevalence than those with greater diversity in host susceptibility. The results reported in this study are very important since a detailed understanding of the population genetic structure of Bulinus is essential to understand the epidemiology of many schistosome parasites.

The spatial and seasonal distribution of Bulinus truncatus, Bulinus forskalii and Biomphalaria pfeifferi, the intermediate host snails of schistosomiasis, in N'Djamena, Chad.

Abstract: There is a paucity of epidemiological and malacological data pertaining to schistosomiasis in Chad. In view of a recently articulated elimination agenda, a deeper understanding of the spatio-temporal distribution of schistosomiasis inter- mediate host snails is pivotal. We conducted cross-sectional malacological surveys during the dry season (April/May 2013) and after the short rainy season (October 2013) in N’Djamena, the capital of Chad. Snails were identified at the genus and species level using morphological keys and molecular DNA barcoding approaches. Those belonging to Bulinus and Biomphalaria were examined for cercarial shedding. Snail habitats were characterised and their predictive potential for the presence of schistosomiasis intermediate host snails explored. Seasonal patterns were studied using geographical information system and kriging in order to interpolate snail abundance data to make predictions at non-sampled locations across N’Djamena. Overall, 413 Bulinus truncatus, 369 Bulinus forskalii and 108 Biomphalaria pfeifferi snails were collected and subjected to cercarial shedding. During the dry season, one Bu. truncatus of 119 snails collected shed Schistosoma spp. cer- cariae (0.84%), while S. mansoni was shed by one of 108 Bi. pfeifferi snails (0.93%). None of the snails collected after the rainy season shed Schistosoma spp. cercariae. The abundance of Bu. truncatus and Bu. forskalii showed an inverse U-shape relationship with the square term of conductivity, i.e. low abundance at the lowest and highest levels of conductivity and high abundance at intermediate levels. Bi. pfeifferi showed a negative, linear association with pH in the dry seasons. It is planned to link these intermediate host snail data to infection data in human populations with the goal to draw a predictive risk map that can be utilised for control and elimination of schistosomiasis in N’Djamena.

Schistosoma haematobium detection in snails by DraI PCR and Sh110/Sm-Sl PCR: further evidence of the interruption of schistosomiasis transmission in Morocco

Abstract: Background: This is the first study in Morocco to estimate snail infection rates at the last historic transmission sites of schistosomiasis, known to be free from new infection among humans since 2004. Screening of large numbers of snails for infection is one way to confirm that Schistosoma haematobium transmission has stopped and does not resurge. Methods: A total of 2703 Bulinus truncatus snails were collected from 24 snail habitats in five provinces of Morocco: Errachidia, El Kelaa des Sraghna, Tata, Beni Mellal, and Chtouka Ait Baha. All visible snails were collected with a scoop net or by hand. We used waders and gloves as simple precautions. Snails were morphologically identified according to Moroccan Health Ministry guide of schistosomiasis (1982). All snails were analyzed in pools by molecular tool, using primers from the newly identified repeated DNA sequence, termed DraI, in the S. haematobium group. To distinguish S. bovis and S. haematobium, the snails were analyzed by Sh110/Sm-Sl PCR that was specific of S. haematobium. Results: The results showed that snails from Errachidia, Chtouka Ait Baha, sector of Agoujgal in Tata and sector of Mbarkiya in El kelaa des Sraghna were negative for DraI PCR; but, snails from remaining snail habitats of El Kelaa des Sraghna, Tata and Beni Mellal were positive. This led to suggest the presence of circulating schistosome species (S. haematobium, S. bovis or others) within these positive snail habitats. Subsequently, confirmation with S. haematobium species specific molecular assay, Sh110/Sm-Sl PCR, showed that none of the collected snails were infected by S. haematobium in all historic endemic areas. Conclusion: The absence of S. haematobium infection in snails supports the argument of S. haematobium transmission interruption in Morocco.

Phylogeny of seven Bulinus species originating from endemic areas in three African countries, in relation to the human blood fluke Schistosoma haematobium

Abstract: Snails species belonging to the genus Bulinus (Planorbidae) serve as intermediate host for flukes belonging to the genus Schistosoma (Digenea, Platyhelminthes). Despite its importance in the transmission of these parasites, the evolutionary history of this genus is still obscure. In the present study, we used the partial mitochondrial cytochrome oxidase subunit I (cox1) gene, and the nuclear ribosomal ITS, 18S and 28S genes to investigate the haplotype diversity and phylogeny of seven Bulinus species originating from three endemic countries in Africa (Cameroon, Senegal and Egypt). The cox1 region showed much more variation than the ribosomal markers within Bulinus sequences. High levels of genetic diversity were detected at all loci in the seven studied species, with clear segregation between individuals and appearance of different haplotypes, even within same species from the same locality. Sequences clustered into two lineages; (A) groups Bulinus truncatus, B. tropicus, B. globosus and B. umbilicatus; while (B) groups B. forskalii, B. senegalensis and B. camerunensis. Interesting patterns emerge regarding schistosome susceptibility: Bulinus species with lower genetic diversity are predicted to have higher infection prevalence than those with greater diversity in host susceptibility. The results reported in this study are very important since a detailed understanding of the population genetic structure of Bulinus is essential to understand the epidemiology of many schistosome parasites.

Schistosomiasis in cattle in Corsica, France.

Abstract: To the Editor: The origin of the human cases of urinary schistosomiasis observed in France was recently identified (1,2). None of these patients had traveled to a disease-endemic area, but all had vacationed in Corsica and had swum in the Cavu River, near Porto-Vecchio in southern Corsica. The letter by Berry et al. to Emerging Infectious Diseases (2) reminded us that bovine schistosomiasis had been reported in Corsica in the past, up through the 1960s, in the same area. In cattle, Schistosoma bovis has been found in Africa and the Middle East (Iraq, Israel), as well as in the Mediterranean Basin, especially in Sicily and Sardinia in Italy, and Corsica, France, where cases were reported as early as 1929 by Emile Brumpt (3,4). In addition, certain Schistosoma blood fluke species, especially S. haematobium and S. bovis, can share the same definitive hosts (humans or animals) and the same intermediate hosts, i.e., Bulinus contortus snails. Cattle, sheep and goats, horses, wild ruminants and rodents can all be definitive hosts of S. bovis. In cattle, the clinical manifestations of infestation are poorly documented. In experimental animals, intermittent diarrhea has been observed, sometimes containing blood or mucus, in addition to a loss of appetite, progressive anemia, and, especially, blood eosinophilia, a sign which, as in humans, indicates that the infestation is recent. Under natural conditions, the disease is believed to be mainly subclinical and chronic. It should be noted that the acute form of the disease is more common in sheep (5). With regard to lesions, the disease is closer to intestinal schistosomiasis (caused by S. mansoni) than to urinary schistosomiasis. The lesions are characterized by the formation of gray-white granulomas ≥5 mmin diameter, or by polyps, and intestinal hemorrhaging due to bleeding of the granulomas formed during migration of the parasite’s eggs to the intestinal lumen. In the liver, granulomas may also be observed, as well as fibrosis of the portal vein. Hepatomegaly and cirrhosis may also be present. These lesions are caused by adult parasites in the mesenteric vessels and the portal vein. The presence of Bulinus truncatus contortus (Michaud) (Mollusca, Gastropoda, Hygrophila) snails was mentioned as early as 1832, and the species was formally identified in 1922 in Corsica. Since that time it has been assumed that this mollusc could be a potential intermediate host for human (6) or bovine (3,7) schistosomiasis. In 1963, Gretillat studied bovine schistosomiasis in Corsica (8). Investigations of Bulinus snails were conducted solely in the southern part of the island, in the area where Brumpt had described their presence 30 years earlier. Bulinus snails were identified in 4 rivers, the Rizzanese, Baraci, Ortolo and Spartano, especially in residual ponds of waterways sometimes quite close to the sea. At 2 sites, unidentifiable cercaria larvae were revealed through dissection (5 of 70 Bulinus snails in the Rizzanese, 26 of 50 in the Baraci). As part of the same study, slaughterhouse examination of 15 cattle from regions where Bulinus snails had been discovered revealed adult Schistosoma in the mesenteric and vesical veins, as well as in the liver and the portal system. In a more comprehensive study (9), Bulinus snails were found in all of Corsica’s coastal rivers, except for those in the northwestern-most part of the island. However, of the 55 bodies of water where Bulinus snails were found, only 1 contained gastropods with Schistosoma cercariae, and results of a search for blood flukes in 220 small rodents (known for being susceptible to S. bovis and captured near bodies of water where Bulinus snails had been observed) were negative. We have found no other documentation on bovine schistosomiasis in Corsica between 1966 and the present time. Has this disease disappeared since the 1960s? Is it still present as an enzootic disease with silent transmission? It should be noted that the disease produces few or no clinical signs and that slaughterhouse detection requires dissection of the circulatory system of the abdominal cavity. In any case, the discovery of human cases of schistosomiasis proves that a human–Bulinus parasitic cycle exists in Corsica, and therefore an animal–Bulinus cycle may exist as well. For the sake of scientific interest, an investigation into the presence of S. bovis in ruminants in Corsica would be worthwhile. Moreover, the fact that both Schistosoma species use the same intermediate host, Bulinus contortus snails, could cause problems with differential diagnosis.

Distribution of Fresh-Water Mollusks of the Gharb Area (Morocco)

Abstract: To assess changes in the fauna of freshwater mollusks in the Gharb Plain (Morocco), 200 sites spread over five districts were surveyed between May 2012 and May 2013. A total of 11 species were identified. Physella acuta and Melanopsis praemorsa were most frequently encountered. Bulinus truncatus, an intermediate host of schistosomiasis in Morocco, and Planorbarius metidjensis, an intermediate host of schistosomiasis, were not harvested. The absence of these species may be due to a combination of climatic, biological and anthropogenic factors related to the changes that have occurred in the region.

Cytokines and Mother Sporocysts in Susceptible and Resistant Bulinus Truncatus Snails Infected with Schistosoma Haematobium

Abstract: The presence of immunoreactive interleukin (IL-2), interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) in addition to the citation of mother sporscytes in cephalopodal musculature in the susceptible and resistance Bulinus truncatus the specific intermediate host for the trematode Schistosoma haematobium were investigated,. Using ELISA tests, Results indicated that the concentration of IL-2-like activity in the susceptible and resistant snails decreased significantly after infection then persisted at low levels until the 4th week post exposure (WPE) in susceptible snails, while in resistant snails elevated during the second WPE, and returned to initial level at 3 and 4 WPE. Susceptible snails had low detectable levels of TNF-α and INF-γ like-activity after infection. However, the resistant snails had significant low levels of TNF-α and INF-γ like-activity from 3 WPE until the 4th WPE without any sign of normalization. Histological sections in the head- foot region of susceptible and resistance B. truncatus infected with S. haematobium, mother sporocysts exists from 1 to 7(day post exposure) DPE, in the susceptible snail the mother sporocysts were found as single, multiple and mature types. No mother sporocysts were appear in the lip and mantle of the snail on 2, 5, 7 DPE and on 1-3, 6 DPE respectively. In the resistant snails few mother sporocysts were found in the lip, mantle and tentacles. The results showed that schistosome-resistant Bulinus can be an alternative strategy for the control of schistosomiasis.