Investigations in Spain following human West Nile virus infections
The Institut de Veille Sanitaire in France contacted the
Spanish authorities on 7 October 2003 regarding the first probable case of
West Nile fever in France. The patient spent half of the incubation period
(15 days) in the south of France and half near to Alicante, Spain.
The health authorities in the area of Alicante have not, to date, detected
any increase in meningo-encephalitis in 2003.
West Nile virus (WNV) activity was last detected in Spain between the 1960s
and the 1980s in the regions of Catalunya, Andalucía, Valencia, and
Galicia (1). Following the outbreak of WNV in horses in France in the year
2000, a research network for arthropod- and rodent-transmitted viral diseases
was established in Spain in 2001. Ongoing research and surveillance projects
carried out in different regions have not detected any WNV activity in the
areas studied. These studies include testing of human sera, sera from migrating
birds, and pools of mosquitoes for West Nile virus and other flaviviruses.
Following the notification of a probable case in France, specific investigations
have been initiated in Spain, including:
||Active search and detection of meningo-encephalitis of unknown origin
in the area of Alicante;
||Systematic testing for WNV in sera from the area archived at the national
reference centre during the past few months;
|| Active search of possible changes in animal health;
||An entomological study and a seroprevalence study in migrating birds
in the area are under discussion.
The initial results of polymerase chain reaction (PCR) tests on sera from
the area archived at the national reference centre during the past few months
are negative for WNV. Results of serological studies will be available soon.
In conclusion, there is no evidence at this point of any cases of WNV in
Spain, nor is there any proof that WNV is circulating in this country. Nevertheless,
a proactive system has been implemented to ensure that appropriate surveillance
procedures are being carried out.