West Nile Fever: Long-Lasting Effects
Even Mild West Nile Illness May Have Lingering Effects; Brain Damage Feared
West Nile Brain Damage Common?
Perhaps the most chilling findings came from psychological and neurological tests.
Among the patients whose West Nile illness wasn't severe enough to put them in the hospital, 15% had moderate-to-severe impairment of executive function. That's the ability to plan, inhibit behavior, and pay sustained attention.
More alarming was the finding that nearly 70% of the patients had abnormal results on a finger-tapping test to look at motor speed. In 43% of the patients, this impairment was severe. These patients were more likely to suffer depressiondepression than were the other patients.
Despite these problems, most of the patients were able to return to a "reasonable level" of daily function. This may be why previous studies -- which mostly looked for disabilities -- find more positive long-term outcomes for West Nile virusWest Nile virus infection.
Carson and colleagues suggest West Nile fever "is not a self-limited benign illness, as previously thought." They suggest it may be a brain infection that leaves behind long-lasting damage.
West Nile virus is spread by mosquitoes. There's no treatment or cure for the infection, so avoiding mosquito bites is the best way to deal with West Nile disease.
August and September are the biggest months for West Nile virus.
This year has been relatively quiet for West Nile so far, with 388 cases of human illness reported in 26 states as of Aug. 15.
But if previous years are any guide, those numbers are sure to go up before mosquitoes wane. In 2003, for example, there were 393 human infections as of Aug. 13 -- and 715 by Aug. 20.