Neutralizing antibodies for dengue virus serotypes 1 and 2 and serotypes 2
and 3 were detected in 1998 in 12 of 53 (22.6%) and 3 of 10 (30.0%) bats sa
mpled in Costa Rica and Ecuador, respectively. Dengue is a consistent healt
h problem in the two Costa Rican communities in which bats were sampled. Th
e high percentage of bats with neutralizing antibodies to dengue virus in t
hese two Costa Rican communities suggests that bats map become infected wit
h dengue virus. This appears to be the case in Costa Rice and Ecuador.