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West Nile virus (WNV) causes West Nile fever and West Nile meningitis, encephalitis and West Nile poliomyelitis. It can infect people, birds, mosquitoes, horses and other animals. In Washington state, the virus was first found in horses and birds in 2002. The first human infection by WNV in Washington state occurred in 2006.
Facts about West Nile virus Mosquito control tips Steps to prevent mosquito bites