The New World alphaviruses eastern equine encephalitis virus (EEEV), Venezuelan equine encephalitis virus (VEEV), and western equine encephalitis virus (WEEV) are all mosquito-borne pathogens originating in North and South America. All three viruses are capable of causing severe illness in animals and humans, with extreme cases leading to encephalitis. Given the lack of commercially available vaccines or treatments, and previous research into these pathogens as potential bioterrorism weapons, all three are of great significance to public health. The aim of our laboratory was to develop a cynomolgus macaque model to study the unique neuropathology of each virus when delivered via an aerosol route, the most likely delivery route for a biological attack. To assess pathogenesis, peripheral blood mononuclear cells (PBMCs) were isolated from whole blood and analyzed by flow cytometry. Inflammation in the central nervous system (CNS) was also evaluated using a LEGENDplex bead based immunological array. Results indicate a substantial increase in the number of CCR2+ myeloid cells in circulation, a receptor important for homing and migration to infected tissue. In addition, inflammatory cytokines MCP-1 (CCL-2), IP-10, IL-6, and IL-8 were substantially upregulated in the CNS tissues and cerebrospinal fluid (CSF) of lethally infected animals. Collectively, this suggests homing and migration of peripheral immune cells to the CNS, and identifies potential markers for future longitudinal studies of alphavirus disease progression and severity
