Investigation Into the Comparative Efficacy of Three West Nile Virus Vaccines in Experimentally Induced West Nile Virus Clinical Disease in Horses

摘要

This is the first report of a comparative vaccine-efficacy trial in horses where West Nile Virus-induced encephalomyelitis was shown in all of the control animals. These studies show differences in the abilities of two commercial vaccines and a live-chimera vaccine to protect against West Nile Virus-induced disease at 28 days post-vaccination in horses. Since its emergence into the United States in 1999, West Nile virus (WNV) has killed a total number of 785 humans, 6000 horses, and an estimated hundreds of thousands of birds. This mosquito-borne encepha-litic flavivirus has caused clinical disease in 19,444 humans and 22,908 horses.1 Using a reproducible model of WNV-induced encephalomyelitis,2 the effi-cacy of a new live-chimera vaccine and two commer-cially available vaccines for prevention of clinical signs of WNV-induced disease was tested in horses.