title: Relative compatibility of Schistosoma mansoni with Biomphalaria sudanica and B. pfeifferi from Kenya as assessed by PCR amplification of the S. mansoni ND5 gene in conjunction with traditional methods.
abstract: BACKGROUND
  Schistosoma mansoni is hosted by several species of Biomphalaria spp. snails in Africa. We were interested in determining if there were differences in compatibility of S. mansoni with Biomphalaria sudanica from Lake Victoria, or with B. pfeifferi from streams and smaller water bodies in Kenya. Does this parasite develop with equal efficiency in both snail species, and does this have implications for transmission in different habitat types?
  
  
  METHODS
  Primers for PCR amplification of the S. mansoni ND5 gene were designed and tested for sensitivity and specificity. We exposed laboratory-reared B. sudanica and field-derived B. pfeifferi to single miracidium infections and at 1, 2, 4, 8, 16 and 24 days post-exposure (dpe), snails were extracted for the PCR assay. Snails were also shed for cercariae and/or dissected prior to extraction. Additionally, B. sudanica and B. pfeifferi were collected from field locations and tested with the PCR assay.
  
  
  RESULTS
  The ND5 PCR assay was sensitive (>0.1 fg S. mansoni genomic DNA) and allowed S. mansoni to be differentiated from other relevant schistosome species or snails. The number of PCR positive snails at 1-4 dpe was higher for B. pfeifferi than for B. sudanica, but not significantly so (P = 0.052). From 8-24 dpe, more B. pfeifferi harbored successfully developing parasites (positive by both dissection and PCR) than did B. sudanica (P = 0.008). At 40 dpe, more B. pfeifferi than B. sudanica shed cercariae or harbored dissection positive/PCR positive infections (P < 0.001). Both immature and failed (dissection negative but PCR positive) S. mansoni infections could also be detected in naturally infected snails of both species.
  
  
  CONCLUSIONS
  The PCR assay detected S. mansoni infections in snails exposed to one miracidium for one day. Both B. sudanica and B. pfeifferi supported full development of S. mansoni, but B. pfeifferi was more compatible, with significantly more dissection positive/PCR positive or shedding infections, and significantly fewer failed infections (dissection negative/PCR positive). This highlights the relatively lower compatibility of B. sudanica with S. mansoni, and suggests the factors responsible for incompatibility and how they might affect transmission of S. mansoni in habitats like Lake Victoria deserve additional study.
authors.affiliation: Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, 87131, USA. lijun80@unm.edu.
authors.forename: Lijun
authors.identifier: http://orcid.org/0000-0001-5073-3753
authors.initials: L
authors.lastname: Lu
authors.affiliation: Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, 87131, USA.
authors.forename: Si-Ming
authors.initials: SM
authors.lastname: Zhang
authors.affiliation: Center for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya.
authors.forename: Martin W
authors.initials: MW
authors.lastname: Mutuku
authors.affiliation: Center for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box 54840-00200, Nairobi, Kenya.
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Mkoji
authors.affiliation: Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, 87131, USA.|Parasitology Division, Museum of Southwestern Biology, University of New Mexico, Albuquerque, 87131, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Loker
mesh_terms: D000818:Animals; D001700:Biomphalaria / Q000469:parasitology*; D015801:Helminth Proteins / Q000235:genetics; D007630:Kenya; D060106:Lakes; D015345:Oligonucleotide Probes / Q000235:genetics; D016133:Polymerase Chain Reaction; D012550:Schistosoma mansoni / Q000235:genetics / Q000302:isolation & purification*; D012680:Sensitivity and Specificity
chemical_list: D015801:Helminth Proteins; D015345:Oligonucleotide Probes
keywords: Biomphalaria pfeifferi; Biomphalaria sudanica; Compatibility; Epidemiology; Kenya; Parasite transmission; Schistosoma mansoni; Schistosomiasis