Doctors fear West Nile virus could be more virulent

Some cases of West Nile virus appear to be attacking the human brain more aggressively than previously seen, raising fears that the virus may have mutated into a more virulent form.

The current West Nile virus epidemic is the worst in the United States in the last decade, but 2012 may become known as the year the epidemic took a turn for the worst, according to the Washington Post.

Neurologists with extensive experience dealing with the mosquito-borne illness say that they have seen cases of the virus damaging the speech, language and thinking centers of the brain. Others have noticed brain damage in young, previously healthy patients.

A scientist for the U.S. Centers for Disease Control and Prevention said that the agency has not found evidence of the virus causing a different form of brain damage, only more severe forms of the same type. He said doctors may be seeing more severe cases this year because of the large number of cases overall.

A Texas virologist's laboratory work supports those who feel the virus has fundamentally changed. Alan Barrett of the University of Texas Medical Branch in Galveston said that samples from the Houston-area show genetic changes.

"This year's virus looks more like the virus from 2002 and 2003," Barrett said, the Washington Post reports.

Barrett said it is too early to tell if the possible new strain is more damaging than those previously seen. It will take time to study the genetics of West Nile samples from across the country. He is currently backlogged.

"We're overwhelmed," Barrett said, according to the Washington Post.