When 69-year-old Catherine Ferguson came down with West Nile virus last summer, it not only attacked her body, leaving her paralyzed, it also went after her mind.
"I didn't know who I was or where I was," she said.
"She could think of what she wanted to say, you could see it on her face, but she couldn't get it out," said Barbara Farley, Ferguson's daughter.
Dr. Art Leis of the Methodist Rehabilitation Center and a number of other West Nile experts say this year's virus appears to have become more invasive and is attacking the brain more aggressively.
"I think three or four of our patients out of the first 12 or 13 had some evidence of language disturbance and that's very different from previous years," Leis said.
Mosquitoes transmit West Nile. This year, there have been more than 5,000 cases-- the most in almost a decade-- and more than 200 people have died.
The Centers for Disease Control does not have any data that shows this year's virus is more dangerous than previous years. But physicians like Leis say it looks like the virus may have mutated.
"I think we have to consider the possibility that the virus has changed its properties," Leis said.
Most people infected with West Nile do not get sick. Symptoms can include fever, headache, fatigue and body aches. People with severe cases can also have disorientation, convulsions and paralysis. That's what Ferguson had. It left her in a wheelchair.
"It's something I have to accept and try to live over," she said.
She says she's just grateful to be alive.
The CDC says warmer weather was a factor in the West Nile outbreak this year.
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