Address for correspondence: Grant L. Campbell, M.D., Ph.D., Division of Vector-Borne Infectious Diseases, CDC, P.O. Box 2087, Fort Collins, CO 80522-2087; Voice: 970-221-6459; fax (970) 221-6476.
GLCampbell{at}cdc.gov
Seroprevalence data suggest that West Nile virus activity in
southern Romania dates to the 1960s or earlier. In the summer
of 1996, southeastern Romania and especially Bucharest experienced
an unprecedented epidemic of West Nile encephalitis/meningitis,
with at least 393 hospitalized cases and 17 deaths. Contributing
factors included a susceptible avian population and urban/suburban
infrastructural conditions that favored the production of large
numbers of
Culex pipiens pipiens. The epidemic ended spontaneously
in early autumn. Results of serosurveys conducted as the epidemic
waned pointed to the recent, novel introduction of West Nile
virus to Bucharest. During 1997-2000, 39 scattered human cases
of clinical West Nile virus infection (mean, 10 per year; range,
5-14 per year)—including 5 (13%) fatal cases—were
diagnosed serologically throughout the region, but epidemic
disease did not recur. Results of limited ecologic surveillance
efforts during 1997-2000 suggested the existence of numerous
focal areas of enzootic West Nile virus activity within the
region. The authors explore the possible factors that led to
the 1996 epidemic, review the ecologic and human data gathered
during the postepidemic period of 1997-2000, summarize the public
health lessons offered by the epidemic and its aftermath, and
speculate on the future of epidemic West Nile virus activity
in southeastern Romania.
