Serologic survey of humans for flavivirus West Nile in Southern Moravia (Czech Republic).

A serosurvey for West Nile virus (WNV) was carried out in 525 persons, using a plaque-reduction neutralization microtest (PRNmicroT) with Vero cells and Egyptian topotype Eg-101 strain as test virus. The blood sera were collected in four South-Moravian districts (Hodonin 44 persons, Breclav 102 persons, Znojmo 170 persons, Jihlava 209 persons) of the Czech Republic in the years 1988 and 1989, and stored at -20 degrees C. Antibodies to WNV were detected in only three humans (0.6% seropositivity): one person each in the districts of Hodonin (2.3% persons positive), Breclav (1.0% positive) and Jihlava (0.5% positive), with the titres of 1:64, 1:32, and 1:32, respectively. All the three sera were negative for antibody to tick-borne encephalitis virus. The results indicate that activity of WNV in southern Moravia was very low before 1990.