Leptospirosis has significantly decreased in Korea since 1988, following th
e leptospiral vaccination programme initiated in 1988. Whether this wholly
explains the decreased incidence is uncertain. As an initial step to answer
this question, infection rates of Leptospira interrogans in field rodents,
Apodemis agrarius, were examined and compared with previous data.
Two hundred and twenty-two A. agrarius were captured during October-Decembe
r 1996. Spirochaetes were isolated from 22 (9.9 %) and leptospiral DNA was
detected in an additional 6 rodents (12.6 %). Subsequent microscopic agglut
ination tests (MAT) classified all these isolates as L. interrogans serogro
up Icterohaemorrhagiae serovar lai. The above data did not significantly di
ffer from previous surveys in 1984-7. There was no significant change of L.
interrogans infection in field rodents following the introduction of the v
accination programme in Korea, Further studies are needed to determine the
role of human vaccination in reducing incidence.