CCL2 and nervous system disorder: It has been shown that neurological disease associated with CHIKV infections has the highest mortality rate of potential atypical disease manifestations [159,160], and neurological complications following CHIKV infection are characterized by elevated TNF-α, IFN-α, IL-6, IL-8, CCL2, CCL5, CCL17, and CXCL9 in CSF in comparison to patients without neurological disease [161].