The virus, which is spread by mosquitoes, surfaced in the United States in 1999. It typically emerges in the spring, with infections peaking in the summer and early fall. During the past three years, cases reported in the United States increased dramatically. In 2001, 66 people were infected, and in 2002, that number rose to 4,156. In 2003, almost 10,000 people were infected and more than 250 died.
The Centers for Disease Control and Prevention and other public health organizations predict that this summer's outbreak could be even more severe.
"We, as a nation, must proactively develop a stronger game plan," said Louis Sullivan, former secretary of the Department of Health and Human Services, in a conference call with reporters. "We must work to strengthen our nation's public health system."
Shelley Hearne, executive director of the nonprofit group Trust for America's Health, said the nation's public health defenses need more personnel and more federal funding. Hearne's organization released a report on the upcoming West Nile season to coincide with Thursday's conference call.
"Public health staffing shortages at the federal, state and local levels hurt our ability to respond to both emerging epidemics and ongoing health threats," Hearne said. "We need to fund workforce programs in proportion to the crucial role they play in our national health defenses."
In each successive year, more people have been infected and the virus has moved west across the country.
"Now that [the virus] has established a strong foothold in the U.S., public health measures should reflect the changing nature of the disease and its potential impacts," the Trust for America's Health report noted. "In five short years, West Nile virus has evolved from an isolated municipal event into a full-blown national epidemic. The projected West Coast emergence, combined with the continued prevalence in the rest of the country, makes the 2004 season an especially dangerous prospect."
Last year, the federally funded Institute of Medicine published The Future of Public Health in the 21st Century, a report that found that a shortage of public health workers, combined with the increased risk of bioterrorism and emerging epidemics, has left a significant hole in the nation's health defenses.