Schistosomiasis japonica in the Philippines: the long-term impact of population-based chemotherapy on infection, transmission, and morbidity.
Olveda RM,
Daniel BL,
Ramirez BD,
Aligui GD,
Acosta LP,
Fevidal P,
Tiu E,
de Veyra F,
Peters PA,
Romulo R,
Domingo E,
Wiest PM,
Olds GR.
Department of Health, University of the Philippines, College of Medicine, Manila, Philippines.
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.
PMID: 8655987 [PubMed - indexed for MEDLINE]