A major outbreak of West Nile virus (WNV) lineage 2 infections was
observed in 2010 in Greece. In order to check the persistence of WNV IgM
antibodies, a second serum sample taken 75-180 days after onset of the
illness from 29 patients with WNV infection was tested. A third sample
was obtained 181-270 days after onset of the illness from 8 of the 12
patients with IgM-positive second sample. Mixed effects linear
regression analysis indicated that the approximate time at which IgM
index became negative was 164 (95% confidence interval, 95% Cl 99-236)
days after the symptoms’ onset. Persistence of IgM antibodies was
observed in 12% of patients at 181-270 days of follow-up. A sharp
decrease in the IgM levels was observed, mainly in patients who had high
IgM index value in the acute phase. All patients were WNV IgG positive
at the follow-up. J. Med. Virol. 83:1857-1860, 2011. (C) 2011
Wiley-Liss, Inc
