EEEV Aerosol Challenge Researchers have observed virus-induced lesions in the olfactory bulb of rodents and non-human primates shortly after an EEEV aerosol challenge . Following an aerosol challenge, EEEV swiftly infects and disseminates throughout the brain and spinal cord of macaques . It has observed the localization of viral particles close to synapses, around axons, and amid myelin sheaths . The axonal transport system transports the virus, which then spreads from neurons to neurons throughout the brain and spinal cord. Neurons are the primary target of EEEV infection. It observed mild to moderate necrotic and inflammatory lesions in both brain regions of all nonhuman primate NHPs. Neuropil vacuolation, satellite disease, necrosis, and neuronal degeneration distinguished the necrotic lesions.