Eggs resembling those of Schistosoma mansoni have been observed in human st
ools collected from the inhabitants of Dhanusha district, in southern Nepal
. In an attempt to determine if S. mansoni was present, 518 sera collected
from subjects from four sites in this district were checked for antibodies
to this parasite, in July 1996 and May 1997, using ELISA. Overall, 94 (18.1
%) of the subjects were deemed seropositive, with the highest seroprevalenc
e (42.7%) at the one site in Chisipani village and the lowest (1.0%) at one
of the three sites in Tulaschichauda village. A follow-up study of Chisipa
ni village, in January 1998, indicated a seroprevalence then of 22.7% (37/1
10). Although possible intermediate hosts, clinical manifestations and geog
raphical distribution have yet to be explored, the present results indicate
that S. mansoni probably does exist in the Dhanusha district of Nepal.