What is the “acute flaccid paralysis” that sometimes occurs with WNV infection?
A. In addition to West Nile fever, meningitis, or encephalitis, some people who become infected with WNV can develop “acute flaccid paralysis”—a sudden onset of weakness in the limbs and/or breathing muscles. In most persons, acute flaccid paralysis is due to the development of West Nile poliomyelitis—an inflammation of the spinal cord that causes a syndrome similar to that caused by the poliovirus. West Nile poliomyelitis was first widely recognized in the United States in 2002. Persons with West Nile poliomyelitis may develop sudden or rapidly progressing weakness. The weakness tends to affect one side of the body more than the other, and may involve only one limb. The weakness is generally not associated with any numbness or loss of sensation, but may be associated with severe pain. In very severe cases, the nerves going to the muscles that control breathing may be affected, resulting in rapid onset of respiratory failure. It is important to recognize that this weakness may occur in
