Volume 19, Number 4—April 2013
West Nile Virus Infection in Belgian Traveler Returning from Greece
|Sample||Date||RT-PCR (Ct value)||WNV ELISA IgM (ratio)||WNV ELISA IgG (ratio)||Flavi IFAT IgM||Flavi IFAT IgG|
|Serum||Aug 15||Positive (45.47)||Positive (25)||Negative||ND||ND|
|CSF||Sep 3||ND||Positive (5.16)||Positive (2.21)||ND||ND|
|Serum||Sep 6||Positive (42.87)‡||Positive (4.76)||Positive (2.63)||WNV positive||WNV positive§|
*WNV, West Nile virus; RT-PCR, reverse transcription PCR; Ct, cycle threshold; Flavi, flavivirus; IFAT, indirect fluorescent antibody technique; ND, not done; CSF, cerebrospinal fluid.
†The ELISA is positive if ratio >1.1 for IgM and >1.5 for IgG. The cutoff value for IFAT is 1/10 for both IgG and IgM.
‡Sequencing revealed a 116-bp sequence perfectly matched to the WNV amplicon and is highly suggestive for WNV lineage 2 on the basis of the presence of 2 specific nucleotides.
§Strongest signal for WNV, weak signal for other flaviviruses (Japanese encephalitis virus, dengue viruses 1–4, yellow fever virus).