CCR5 and tick-borne encephalitis: No association of CCR5Δ32 heterozogosity with WNV infection was observed, suggesting that even a reduced expression of CCR5 is sufficient for protection [39], but in the European patients, increased TBE risk was associated with CCR5Δ32 heterozogosity, as if the quantitatively changed CCR5 expression was sufficient to alter susceptibility to TBEV [41].