Recently, the nsP4 coding region of Alphavirus RNA was chosen as the target for genus-specific RT-PCR, and all alphaviruses, including Barmah Forest, Chikungunya, Mayaro, O'nyong-nyong, Ross River, Semliki Forest, Sindbis, Eastern equine encephalitis, Western equine encephalitis, and Venezuelan equine encephalitis viruses, were positive using the generic Alphavirus PCR [31]. This evidence concerns the gene PRSS57 and western equine encephalitis.