This virus is enzootic in many parts of the Americas. Epidemics of VEE occur when strains of this endemic form mutate and give rise to an epidemic strain of virus capable of causing disease in equidae and humans. The mechanism of development of these virus strains is still not clear, nor is the mechanism of their release into the greater population, capable of causing epidemics (Sahu, 2003). VEE is found in high levels in the blood of equidae which can act as an amplifier in the epidemiological cycle. This differs from other causal agents of equine encephalomyelitis where, due to insufficient virus levels in the blood for them to be infectious, equines are the dead end host. | This virus is enzootic in many parts of the Americas. Epidemics of VEE occur when strains of this endemic form mutate and give rise to an epidemic strain of virus capable of causing disease in equidae and humans. The mechanism of development of these virus strains is still not clear, nor is the mechanism of their release into the greater population, capable of causing epidemics (Sahu, 2003). VEE is found in high levels in the blood of equidae which can act as an amplifier in the epidemiological cycle. This differs from other causal agents of equine encephalomyelitis where, due to insufficient virus levels in the blood for them to be infectious, equines are the dead end host. |