West Nile Virus Positive Blood Donation and Subsequent Entomological Investigation, Austria, 2014

Kolodziejek, Jolanta; Seidel, Bernhard; Jungbauer, Christof; Dimmel, Katharina; Kolodziejek, Michael; Rudolf, Ivo; Hubálek, Zdenek; Allerberger, Franz; Nowotny, Norbert

The Austrian WNV strains investigated here carry only a few suspected neuroinvasiveness and pathogenicity markers. Interestingly, the highly conserved N-glycosylation site N-154 of the E gene, which has been associated with significant human outbreaks including the North American epidemic [13] and which was initially identified in both the Austrian human plasma and mosquito pool, mutated to lysine (K-154) during the virus isolation process of the plasma sample in suckling and adult mice. Despite (or because) of lack of glycosylation of this site, the WNV plasma isolate turned out to be highly neuroinvasive for adult mice. Such a mutation was also observed among the Russian WNV strains isolated in Volgograd 1999 from human brains indicating their high neuroinvasivness and pathogenicity (GenBank acc. nos. AY277252 and AF317203) [21] . Studies in mice revealed that-while both non-and E-glycosylated WNV strains were equally neurovirulent-the latter were more neuroinvasive [13] . The WNV strain investigated in our study had fortunately caused only mild febrile illness in the Viennese patient, possibly related to the comparatively young age of the patient. In addition, we do not expect that the neuroinvasive properties of the plasma isolate were due to the presence of lysine at position E-154 or due to the lack of the N-154 glycan, however this exceptional point mutation observed in the present study requires further analysis.