title: Real-time PCR demonstrates high prevalence of Schistosoma japonicum in the Philippines: implications for surveillance and control.
abstract: BACKGROUND
  The Philippines has a population of approximately 103 million people, of which 6.7 million live in schistosomiasis-endemic areas with 1.8 million people being at risk of infection with Schistosoma japonicum. Although the country-wide prevalence of schistosomiasis japonica in the Philippines is relatively low, the prevalence of schistosomiasis can be high, approaching 65% in some endemic areas. Of the currently available microscopy-based diagnostic techniques for detecting schistosome infections in the Philippines and elsewhere, most exhibit varying diagnostic performances, with the Kato-Katz (KK) method having particularly poor sensitivity for detecting low intensity infections. This suggests that the actual prevalence of schistosomiasis japonica may be much higher than previous reports have indicated.
  
  
  RESULTS
  Six barangay (villages) were selected to determine the prevalence of S. japonicum in humans in the municipality of Palapag, Northern Samar. Fecal samples were collected from 560 humans and examined by the KK method and a validated real-time PCR (qPCR) assay. A high S. japonicum prevalence (90.2%) was revealed using qPCR whereas the KK method indicated a lower prevalence (22.9%). The geometric mean eggs per gram (GMEPG) determined by the qPCR was 36.5 and 11.5 by the KK. These results, particularly those obtained by the qPCR, indicate that the prevalence of schistosomiasis in this region of the Philippines is much higher than historically reported.
  
  
  CONCLUSIONS
  Despite being more expensive, qPCR can complement the KK procedure, particularly for surveillance and monitoring of areas where extensive schistosomiasis control has led to low prevalence and intensity infections and where schistosomiasis elimination is on the horizon, as for example in southern China.
authors.affiliation: Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia; Discipline of Epidemiology and Biostatistics, School of Population Health, University of Queensland, Brisbane, Australia.
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Gordon
authors.affiliation: Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines.
authors.forename: Luz P
authors.initials: LP
authors.lastname: Acosta
authors.affiliation: Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia.
authors.forename: Geoffrey N
authors.initials: GN
authors.lastname: Gobert
authors.affiliation: Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines.
authors.forename: Remigio M
authors.initials: RM
authors.lastname: Olveda
authors.affiliation: Griffith Health Institute, Griffith University, Queensland, Australia.
authors.forename: Allen G
authors.initials: AG
authors.lastname: Ross
authors.affiliation: Discipline of Epidemiology and Biostatistics, School of Population Health, University of Queensland, Brisbane, Australia.
authors.forename: Gail M
authors.initials: GM
authors.lastname: Williams
authors.affiliation: Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia; Discipline of Epidemiology and Biostatistics, School of Population Health, University of Queensland, Brisbane, Australia; Research School of Population Health, College of Medicine, Biology and Environment, the Australian National University, Canberra, Australia.
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Gray
authors.affiliation: University of Georgia, College of Veterinary Medicine, Athens, Georgia, United States of America.
authors.forename: Donald
authors.initials: D
authors.lastname: Harn
authors.affiliation: Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia.
authors.forename: Yuesheng
authors.initials: Y
authors.lastname: Li
authors.affiliation: Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia.
authors.forename: Donald P
authors.initials: DP
authors.lastname: McManus
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010679:Philippines / Q000453:epidemiology; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012554:Schistosomiasis japonica / Q000453:epidemiology* / Q000517:prevention & control