CDC warns early West Nile season could herald severe outbreak
The CDC reports the earliest start to West Nile virus activity in over 20 years, with a high proportion of neuroinvasive cases and spread across 23 states, prompting calls for heightened mosquito prevention.
The United States is experiencing the earliest onset of West Nile virus activity in more than two decades, according to the Centers for Disease Control and Prevention. By the end of June, 48 cases had been reported, and nearly 80% involved neuroinvasive disease, which can affect the brain and spinal cord. The CDC notes that West Nile activity has been detected in 23 states, the highest number for this point in the season in a decade.
"You can basically multiply that number by 30, and that’s how many people are actually sick," said Dr. Lyle Petersen, director of the Division of Vector-Borne Diseases at the CDC.
Experts highlighted that adults over 60 are at greater risk of severe complications. Dr. Daniel Pastula, chief of neuro-infectious diseases at the University of Colorado-Anschutz, urged residents in high-risk areas, such as Maricopa County, Arizona, to adopt mosquito bite-prevention measures.
"I’d say to your readers and watchers who are in Arizona, particularly around Phoenix, I would be taking mosquito bite prevention seriously," Pastula said.
There are no specific treatments for the virus, and while vaccines exist for horses, human vaccines remain in early-stage trials. Officials emphasized that prevention—using repellents, eliminating standing water, and supporting local mosquito-control programs—remains the most effective strategy.
"Improving support and funding for vaccine development, particularly West Nile virus, is incredibly important to help reduce the burden of disease," Pastula added.