title: Is PCR the Next Reference Standard for the Diagnosis of Schistosoma in Stool? A Comparison with Microscopy in Senegal and Kenya.
abstract: BACKGROUND
  The current reference test for the detection of S. mansoni in endemic areas is stool microscopy based on one or more Kato-Katz stool smears. However, stool microscopy has several shortcomings that greatly affect the efficacy of current schistosomiasis control programs. A highly specific multiplex real-time polymerase chain reaction (PCR) targeting the Schistosoma internal transcriber-spacer-2 sequence (ITS2) was developed by our group a few years ago, but so far this PCR has been applied mostly on urine samples. Here, we performed more in-depth evaluation of the ITS2 PCR as an alternative method to standard microscopy for the detection and quantification of Schistosoma spp. in stool samples.
  
  
  RESULTS
  Microscopy and PCR were performed in a Senegalese community (n = 197) in an area with high S. mansoni transmission and co-occurrence of S. haematobium, and in Kenyan schoolchildren (n = 760) from an area with comparatively low S. mansoni transmission. Despite the differences in Schistosoma endemicity the PCR performed very similarly in both areas; 13-15% more infections were detected by PCR when comparing to microscopy of a single stool sample. Even when 2-3 stool samples were used for microscopy, PCR on one stool sample detected more infections, especially in people with light-intensity infections and in children from low-risk schools. The low prevalence of soil-transmitted helminthiasis in both populations was confirmed by an additional multiplex PCR.
  
  
  CONCLUSIONS
  The ITS2-based PCR was more sensitive than standard microscopy in detecting Schistosoma spp. This would be particularly useful for S. mansoni detection in low transmission areas, and post-control settings, and as such improve schistosomiasis control programs, epidemiological research, and quality control of microscopy. Moreover, it can be complemented with other (multiplex real-time) PCRs to detect a wider range of helminths and thus enhance effectiveness of current integrated control and elimination strategies for neglected tropical diseases.
authors.affiliation: Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands; Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Lynn
authors.initials: L
authors.lastname: Meurs
authors.affiliation: Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Eric
authors.initials: E
authors.lastname: Brienen
authors.affiliation: Laboratory of Bacteriology and Virology, Aristide Le Dantec Teaching Hospital, Dakar, Senegal.
authors.forename: Moustapha
authors.initials: M
authors.lastname: Mbow
authors.affiliation: Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Ochola
authors.affiliation: Laboratory of Bacteriology and Virology, Aristide Le Dantec Teaching Hospital, Dakar, Senegal.
authors.forename: Souleymane
authors.initials: S
authors.lastname: Mboup
authors.affiliation: Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
authors.forename: Diana M S
authors.initials: DM
authors.lastname: Karanja
authors.affiliation: Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: W Evan
authors.initials: WE
authors.lastname: Secor
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Katja
authors.initials: K
authors.lastname: Polman
authors.affiliation: Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Lisette
authors.initials: L
authors.lastname: van Lieshout
mesh_terms: D000818:Animals; D005243:Feces / Q000469:parasitology*; D006801:Humans; D007630:Kenya / Q000453:epidemiology; D008853:Microscopy / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012015:Reference Standards; D012550:Schistosoma mansoni / Q000302:isolation & purification*; D012555:Schistosomiasis mansoni / Q000175:diagnosis* / Q000453:epidemiology; D012675:Senegal / Q000453:epidemiology