West Nile Virus (WNV) arrived in metropolitan New York in fall 1999. Since then, it has spread steadily southwards and westwards. In anticipation of its arrival in Texas in summer 2002, the Zoo launched a vaccination program using the Ft. Dodge equine vaccine. The program consisted of vaccinating initially all high-risk birds, known highly susceptible species, endangered species, and those housed outdoors. To date, WNV infections have been seen in several species.
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