Serological Evidence of Tick-Borne Encephalitis and West Nile Virus Infections Among Children with Arthritis in Turkey.

Tick-borne encephalitis virus (TBEV) and West Nile virus (WNV) are mainly transmitted by arthropod vectors to vertebrate hosts including humans, resulting in fever and neurological signs. The aim of this study was to investigate the presence of antibodies to TBEV and WNV, and TBEV-RNA and WNV-RNA in Turkish children with fever and/or arthritis. For this purpose, 110 sera and buffy-coat samples were collected; sera were analyzed by indirect enzyme-linked immunosorbent assay for the presence of IgM and IgG antibodies to TBEV and WNV, and buffy-coat-derived white blood cells were analyzed by quantitative real-time RT-PCR for TBEV-RNA and WNV-RNA. IgM antibodies to TBEV were detected in five children between the ages of 3 and 7 years; no IgG antibodies to TBEV were detected. IgG antibodies to WNV were detected in two children and IgM antibodies to WNV were detected in six children, between the ages of 3 and 7 years. One of the children had IgM antibodies to WNV and to TBEV. Children who had antibodies to TBEV and WNV had fever and/or arthritis but no obvious neurological signs. Molecular diagnostic approaches revealed that neither TBEV-RNA nor WNV-RNA was present in any of the buffy-coat samples, not even in children with IgM-specific antibodies. Our serological results indicate that children in Turkey are exposed to TBEV and WNV.