Federal health officials say that West Nile virus cases are up 40 percent since last week and are on pace to rival the record years of 2002 and 2003.
The Centers for Disease Control and Prevention has confirmed 1,590 cases of the mosquito-borne disease and 66 deaths so far this year. Half of the cases are in Texas.
Health officials think that cases have peaked or are peaking now, but likely will continue through October. The disease first appeared in the United States in 1999, and health officials say this summer's hot, dry weather may have contributed to the current boom in cases.
The CDC also says it does not expect Hurricane Isaac to have much of an impact on cases in Southern states.
Explore further: Officials: West Nile outbreak 1 of largest in US