Autochthonous west nile virus infection outbreak in humans, Leipzig, Germany, August to September 2020

Abstract

Following a distinct summer heat wave, nine autochthonous cases of West Nile fever and West Nile neuroinvasive disease, including one fatality, were observed in Leipzig, Germany, in August and September 2020. Phylogenetic analysis demonstrated close relationships in viruses from humans, animals and mosquitos in eastern Germany, obtained during the preceding 2 years. The described large cluster of autochthonous West Nile virus infections in Germany indicates endemic seasonal circulation of lineage 2 viruses in the area. In August and September 2020, seven cases of West Nile neuroinvasive disease (WNND) and two cases of West Nile fever (WNF) were identified in patients at the Leipzig University Hospital, in eastern Germany. Five cases fulfilled the European Union case definitions for laboratory confirmed WNV infections and four cases were classified as probable WNV infections [1]. Here we describe the cases with their clinical characteristics and exact virological findings.