West Nile virus infection in South-eastern Europe and in the Eastern Mediterranean area

Abstract

The West Nile virus (WNV) was identified in Uganda in 1937. This virus appeared in the Mediterranean area in the early 1950s, causing an outbreak in Egypt. Since then, WNV caused a series of outbreaks, in human and/or horses, especially in North-Africa and in the Middle East. In the last few decades, the lineage 1 of West Nile started to cause sporadic cases and outbreaks of West Nile fever and neuroinvasive disease in Southern and Eastern Europe, and a large outbreak was reported in Romania in 1997; then, sporadic cases continued to be reported in central and southern Europe for years. Since 2010, West Nile has reemerged in Europe and in the Mediterranean area. Studies of molecular epidemiology show a co-circulation of WNV lineage 1 and lineage 2 in several European countries. In particular, WNV lineage 2 appears now to be established in South-eastern Europe and in the Balkans. This suggests that WNV is continuously reintroduced in this geographical area. Specifically, the two lineages of WNV are dispersed throughout Europe after arriving through bird migration, following the western and the eastern routes. The latter route is likely to be involved in the emergence and reemergence of WNV infection in South-eastern Europe, where this viral infection represent an important public health challenge. J Microbiol Infect Dis 2014; Special Issue 1: S10-S16