West Nile Virus Death Toll Climbs 35 Percent In One Week, But May Be Peaking
September 13, 2012

West Nile Virus Death Toll Climbs 35 Percent In One Week, But May Be Peaking

Lawrence LeBlond for redOrbit.com - Your Universe Online

US cases of West Nile virus (WNV) have climbed more than a third in the past week, according to federal health officials on Wednesday. However, there are signs that the worst is over and numbers of cases are expected to decline.

“We think the worst part of the epidemic is behind us,” said Dr. Lyle Petersen, director of the US Centers for Disease Control and Prevention's Division of Vector-Borne Diseases. Unless we see a surprising increase in the next week, he said Wednesday´s briefing on the health scare will be the final one for the 2012 West Nile virus season.

Still, government data show that the 2012 outbreak is among the most severe on record. So far, 2,636 cases have been reported, up from 1,993 just last week, the CDC said in its weekly WNV update. A total of 118 people have died from the disease, a 35-percent climb from last week´s 87 reported deaths. The disease has been reported in 48 US states, absent from Hawaii and Alaska only.

Six US states have been responsible for more than 60 percent of the cases reported this year: Texas, South Dakota, Mississippi, Michigan, Oklahoma, and Louisiana. Texas alone accounts for nearly 40 percent of human cases, according to the CDC.

The CDC continues to work with state health officials in Louisiana and Mississippi in the aftermath of Hurricane Isaac, Peterson told CNN, adding that neither state has seen a large increase in cases after the storm, even though health officials had predicted one.

Of the cases reported to the CDC this year, about 53 percent were of the neuroinvasive form of the disease, which can lead to meningitis and encephalitis and can be deadly. The milder form of the disease produces flu-like symptoms and is rarely fatal.

While officials believe this is the peak for infections, some will continue through October, and severe illness and death reports are expected to keep pouring in for months to come, CDC officials said.

West Nile outbreaks are generally unpredictable, but are more severe in seasons with hotter temperatures. Experts also note that years when bird and mosquito populations are aligned just right, larger outbreaks can occur.