Texas has seen at least 40 deaths from West Nile virus this year. (Wikimedia Commons)

Officials from the U.S. Centers for Disease Control and Prevention said Wednesday that the number of confirmed cases rose by 25 percent last week to 1,993, although only the most serious infections--about 2 to 3 percent--are reported to the government.

Most people who are infected by the virus do not develop severe symptoms, and some never even know they were infected. About half of the reported cases are in Texas, which has seen at least 40 deaths so far, according to the Washington Post.

Mississippi, South Dakota, Oklahoma and Louisiana have also seen high rates of infection.

The number of deaths rose to 87, up from 65 a week ago, but seems unlikely to break the record of 260 set in 2002-03. The outbreak probably peaked in August, but the number of new cases will likely continue to mount until October, CDC officials said.

Read the full story at the Los Angeles Times or the Washington Post. For more of Neon Tommy's coverage of West Nile virus, click here.