Antibody response in horses following experimental infection with West Nile Virus lineages 1 and 2.

West Nile virus (WNV) has re-emerged as an important pathogen for humans and horses, which are considered to be incidental 'dead-end' hosts. We have demonstrated that horses are susceptible to experimental infection with WNV and that horses infected with either WNV lineage 1 or lineage 2 elicit a similar antibody profile in serum samples. These data suggest that virus-neutralizing antibody responses persist for longer than WNV-specific IgM levels in serum and that there are not any notable differences in the antibody profile following experimental infection of horses with either WNV lineage 1 and lineage 2 viruses. Furthermore, the duration of IgM appears to be short-lived in horses and may be useful for identifying and differentiating recent infections from previously exposed animals.