- Author: Kathy Keatley Garvey
The Centers for Disease Control and Prevention (CDC) recorded 2,873 cases in 2012, including 286 deaths. The disease is now "established" in the United States and is here to stay, according to the CDC.
Where did WNV virus come from? How is it spread? Can we predict when and where outbreaks will occur?
Those are some of the questions answered in the academy's free online publication. A video is also posted on that web site.
The Academy convened 22 of the world’s leading experts on West Nile virus in March 2013 to consider and answer some of the most frequently asked questions about West Nile virus. The resultant report provides non-technical, science-based answers to questions that people may have about the virus.
William Reisen, internationally renowned for his comprehensive research on mosquitoes, especially those that transmit encephalitis and WNV, was one of two experts from the systemwide University of California consulted for the publication. The other was Philip Norris, a physician with the Blood Systems Research Institute and UC San Francisco.
Reisen directs the UC Davis-based Center for Vectorborne Diseases, and is a professor in the Department of Pathology, Microbiology and Immunology and a graduate student advisor with the UC Davis Department of Entomology and Nematology. Last year he received the international Harry Hoogstral Award for “outstanding achievements in the field of medical entomology.”
Questions on the online publication include:
1. West Nile virus in the news: what happened in 2012?
2. How did WNV get to the United States?
3. How did WNV spread across the country so quickly?
4. How do people get infected with WNV?
5. Why do some people get West Nile fever or neuroinvasive disease? Did they become infected with a “bad” virus?
6. Why was 2012 so bad?
7. If we know what conditions cause WNV outbreaks, can we predict when a new outbreak will emerge and what its severity might be?
WNV, initially discovered in Uganda, is transmitted by the bite of an infected mosquito. It was first detected in the Americas--New York City--in 1999. Within four years, the disease had spread to every state in the contiguous United States.
The publication indicates that "your risk of developing West Nile fever or neuroinvasive disease greatly increases with age and if your infection is transplant tissue associated. In fact, the risk of WNND increases roughly two times for every decade of life. For the younger population, less than 1 in 700 will develop neurological symptoms, but this ration increases to as much as 1 in 50 in those aged 60 or older."
In 2012, "the central United States reported the highest number of West Nile severe disease cases, with Texas shouldering 29 percent of the disease burden. In fact, what made the Texas outbreak so striking is that just four counties in the Dallas/Fort Worth area accounted for 9012 out of 1,868 total reported West Nile cases in the state. Other states hit with large West Nile outbreaks were California, Illinois, Louisiana and Michigan--together the top five states suffered 56 percent of the reported national neuroinvasive disease cases."