Schistosomiasis japonica in the Philippines: the long-term impact of population-based chemotherapy on infection, transmission, and morbidity.
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.
Olveda
R M
RM
Department of Health, University of the Philippines, College of Medicine, Manila, Philippines.
Daniel
B L
BL
Ramirez
B D
BD
Aligui
G D
GD
Acosta
L P
LP
Fevidal
P
P
Tiu
E
E
de Veyra
F
F
Peters
P A
PA
Romulo
R
R
Domingo
E
E
Wiest
P M
PM
Olds
G R
GR
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
D000980:Antiplatyhelmintic Agents; D012556:Schistosomicides; D011223:Praziquantel