title: Polymerase chain reaction (PCR) investigations of prepatent Schistosoma haematobium cercariae incidence in five water bodies, South West, Nigeria.
abstract: This study investigated the levels of prepatent S. haematobium infection in water samples collected from Schistosomiasis haematobium transmission namely: International Institute of Tropical Agriculture (IITA) river and Eleyele river in Oyo state, Oyan dam and Shokori river in Ogun state, Badagry Lagoon and Lagoon (University of Lagos, Lagos state).
  
  
  METHODS
  Polymerase chain reaction (PCR) assay amplifying the Dra I repeated sequence of S. haematobium cercariae from the water samples was used. Samples of cercariae obtained from a laboratory population of Bulinus globosus and Bulinus rohlfsi snails were assayed following DNA extraction as control. Physico-chemical parameters of the water bodies were determined.
  
  
  RESULTS
  Physico-chemical parameters showed that salinity, conductivity and total dissolved solids were relatively high in the Lagoon front samples (41.91 ppt, 62400.87 micros/cm, 31000.14 mg/L and 7.79), and low in the river samples (13.27 ppt, 1325.67 micros/cm, 11470 mg/L and 8.36 respectively) while pH were similar. PCR showed that 3 out of the 6 water bodies sampled namely IITA river, Eleyele river and Oyan Dam are S. haematobium endemic sites as they gave positive signals.
  
  
  CONCLUSIONS
  Three surveyed sites with relatively low salinity namely IITA river, Eleyele river and Oyan dam are high S. haematobium endemic areas and schistosomes survive perhaps best in low salinity environment. PCR could be a more valuable tool in the study of incidence and prevalence of S. haematobium infection compared with conventional cercariae shedding method. On the known strength of focal effects of environmental conditions, implications of these results in the epidemiology and design of control activities are encouraging.
authors.affiliation: Department of Biochemistry, College of Medicine, University of Lagos, P.M.B 12003, Lagos, Nigeria. akande_idowu@yahoo.com
authors.forename: I S
authors.initials: IS
authors.lastname: Akande
authors.forename: A A
authors.initials: AA
authors.lastname: Odetola
authors.forename: D O
authors.initials: DO
authors.lastname: Osamudien
authors.forename: M A
authors.initials: MA
authors.lastname: Fowora
authors.forename: E A
authors.initials: EA
authors.lastname: Omonigbehin
mesh_terms: D000818:Animals; D002033:Bulinus / Q000469:parasitology*; D058487:Cercaria; D004197:Disease Reservoirs / Q000469:parasitology / Q000706:statistics & numerical data; D004199:Disease Vectors; D019353:Endemic Diseases / Q000706:statistics & numerical data*; D062665:Epidemiological Monitoring; D015994:Incidence; D009549:Nigeria / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000379:methods; D015995:Prevalence; D045483:Rivers / Q000737:chemistry / Q000469:parasitology; D012548:Schistosoma haematobium / Q000235:genetics / Q000302:isolation & purification; D012553:Schistosomiasis haematobia / Q000453:epidemiology / Q000469:parasitology; D060753:Water Quality