DNA ‘barcoding’ of Schistosoma mansoni across sub-Saharan Africa supports substantial within locality diversity and geographical separation of genotypes

Schistosomiasis in pre-school-age children and their mothers in Chikhwawa district, Malawi with notes on characterization of schistosomes and snails

“…In order to retrieve schistosome eggs for DNA barcoding, pooled stool or urine samples were obtained from infected children at Kapsasule, Mpangeni and Mwaliga ( see Figure 1) and processed as previously decribed [39-41]. Eggs or hatched miracidia were harvested by pippette in 3 μl of water then placed onto FTA indicator cards.…”

“…4.6 (http://www.genecodes.com). Sequences were then compared against those in EMBL/Genbank using the Basic Local Alignment Search Tool (BLAST) to ascertain which of the known groups of S. haematobium (Group I or II) [40] and S. mansoni (Group I, II, III, IV or V) would be assigned [41]. …”

Intestinal schistosomiasis in chimpanzees on Ngamba Island, Uganda: observations on liver fibrosis, schistosome genetic diversity and praziquantel treatment

“…This group contains some abundant DNA barcodes as well as rarely observed ones, and sequences from this group have been found throughout Lake Victoria . It has been previously hypothesized that this corresponds to a separate 'lineage' of S. mansoni, as defined by Morgan and colleagues (Morgan et al 2005) and corroborated by Stothard et al (2009) and Webster et al (2012), but without a re-analysis of a different fragment of the cox1 gene (which would require additional sampling), this cannot be comprehensively determined. If it is indeed a separate lineage, then it is worth noting that certain individuals, for example Sunday, Surprise and Rutoto (intriguingly not Kidogo) appear to be infected with multiple lineages of S. mansoni.…”

Advocacy, policies and practicalities of preventive chemotherapy campaigns for African children with schistosomiasis

“…It is also known that poor cure rates are reported in communities with a heavy intensity of infections [85], thus even if the drug is killing the vast majority of worms, there may still be residual worms that survive initial treatment [15]. Also different isolates of schistosomes have variable levels of tolerance to PZQ [86], likely due to extensive genetic variation within and between worms [66,67]. Hence, regular assessment of the performance of PZQ is recommended by WHO with new standard operating procedures that have been designed as a first-line guard to detect worrisome performance [15].…”

“…Extensive fieldwork was undertaken, often alongside control teams, and was based in Senegal, Niger, Cameroon, Zambia, Uganda, Tanzania and Kenya. EU-CONTRAST was judged to be very successful with new insights provided into genetic diversity of schistosomes (inclusive of the detection of novel hybrid worms that have a zoonotic cycle) [66,67], innovative mapping and 'ground-truthing' studies of disease distributions [68,69], assessment of the performance of PZQ in coinfection settings (i.e., children with both intestinal and urogenital schistosomiasis) [70,71], socio-economic assessments of treatment compliance and participatory hygiene and sanitation transformation method [72] as well as the development of novel DNA assays to detect schistosomes in the aquatic snail stage (essential for transmission detection), with potential in human diagnostics [73].…”