title: Schistosomiasis japonica in the Philippines: the long-term impact of population-based chemotherapy on infection, transmission, and morbidity.
abstract: The long-term impact of annual case-finding and chemotherapy with praziquantel on schistosomiasis japonica was examined in an 8-year longitudinal study in the Philippines. The prevalence, incidence, and intensity of infection and schistosome-induced hepatomegaly significantly decreased within 3-4 years of treatment and then stabilized despite continual population-based chemotherapy. Hepatomegaly rapidly developed in acutely infected persons, with 82% of subjects developing hepatic enlargement within 2 years of reinfection. These data suggest that abrupt discontinuation of current control measures in the Philippines may result in a rapid rebound in morbidity. Age-dependent acquired resistance to reinfection also developed in subjects chronically exposed to schistosomiasis japonica, suggesting that a vaccine may represent an alternative approach for control of this parasitic infection.
authors.affiliation: Department of Health, University of the Philippines, College of Medicine, Manila, Philippines.
authors.forename: R M
authors.initials: RM
authors.lastname: Olveda
authors.forename: B L
authors.initials: BL
authors.lastname: Daniel
authors.forename: B D
authors.initials: BD
authors.lastname: Ramirez
authors.forename: G D
authors.initials: GD
authors.lastname: Aligui
authors.forename: L P
authors.initials: LP
authors.lastname: Acosta
authors.forename: P
authors.initials: P
authors.lastname: Fevidal
authors.forename: E
authors.initials: E
authors.lastname: Tiu
authors.forename: F
authors.initials: F
authors.lastname: de Veyra
authors.forename: P A
authors.initials: PA
authors.lastname: Peters
authors.forename: R
authors.initials: R
authors.lastname: Romulo
authors.forename: E
authors.initials: E
authors.lastname: Domingo
authors.forename: P M
authors.initials: PM
authors.lastname: Wiest
authors.forename: G R
authors.initials: GR
authors.lastname: Olds
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000980:Antiplatyhelmintic Agents; D002648:Child; D002675:Child, Preschool; D005260:Female; D006529:Hepatomegaly / Q000469:parasitology; D006801:Humans; D015994:Incidence; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010679:Philippines / Q000453:epidemiology; D011223:Praziquantel / Q000627:therapeutic use*; D015995:Prevalence; D012554:Schistosomiasis japonica / Q000150:complications / Q000188:drug therapy* / Q000453:epidemiology / Q000635:transmission*; D012556:Schistosomicides / Q000627:therapeutic use*; D017678:Sex Distribution; D013997:Time Factors
chemical_list: D000980:Antiplatyhelmintic Agents; D012556:Schistosomicides; D011223:Praziquantel