WASHINGTON — The number of West Nile virus cases reported in the United States through early September is the highest year-to-date total since the mosquito-borne disease was first detected in this country in 1999, federal officials said Wednesday. The number of fatalities had jumped by nearly a third from the previous week, they said.
Texas continues to be the state hit hardest, accounting for about half of all reported U.S. cases this year. Aerial spraying of insecticide in some areas has reduced the population of mosquitoes that carry the virus, officials there said. But the number of human cases is expected to rise through October because of the lag time between infection and reporting of the illness.
As of Tuesday, a total of 1,993 cases nationwide, including 87 deaths, had been reported to the U.S. Centers for Disease Control and Prevention, a 25 percent increase in the number of cases and a 32 percent increase in deaths from the previous week.
Asked about recent disease outbreaks, including the hantavirus outbreak traced to Yosemite National Park, Lyle Petersen, director of the CDC division of vector-borne infectious diseases, said pathogens are spreading faster because people and goods are moving around the planet at record rates. "The world is a smaller place right now," he said.
U.S. health officials have notified 39 countries that their citizens might be at risk from the rodent-borne hantavirus after traveling recently to Yosemite. Six hantavirus cases, two of which were fatal, have been linked to the park. The CDC said that as many as 10,000 people were at risk after staying in Yosemite's "signature tent cabins" between June 10 and Aug. 24.
For Texas, 2012 is "the worst year ever for West Nile virus," the state health commissioner, David Lakey, told reporters during a conference call. The state had 1,013 confirmed cases and 40 deaths.