West Nile Virus Spreads to 32 States; 8 Dead as Peak Season Looms

West Nile virus is spreading across the country as summer reaches its hottest weeks. By mid-August, the disease had been confirmed in 32 states, with 222 people infected and at least eight dead. The virus is moving fastest in the Southwest: Arizona alone accounts for 76 cases, Texas has reported 31, and California 29. What makes these numbers alarming is not just their size but their composition. Of the 222 infections, 156 are neuroinvasive cases—the most dangerous form, the kind that attacks the brain and nervous system, that puts people in hospitals, that can leave them permanently changed.

The virus itself is simple in its mechanics. Mosquitoes pick it up when they feed on infected birds. Those mosquitoes then pass it to humans. The CDC's surveillance maps show the virus is already circulating in mosquitoes and birds across regions where no human cases have yet been detected, a sign that the outbreak is still gathering momentum. Health officials are bracing for what comes next. West Nile activity typically peaks in late summer and early fall—the weeks ahead.

Most people who get infected never know it. The CDC estimates that roughly four out of five infected people have no symptoms at all. Another group develops mild illness: fever, headache, body aches, sometimes a rash. But in a small fraction of cases, the virus turns severe. High fever, severe headache, neck stiffness, confusion, tremors, muscle weakness, vision loss, numbness, paralysis. Less than one percent of infected people reach this stage, but when they do, hospitalization is often necessary. About one in ten of those with severe neurologic disease dies. The others may recover over weeks or months, though some never fully do.

The eight deaths reported so far this season—five in Arizona, three in California—represent the human weight of these statistics. They are also a preview. Older adults face the highest risk. People 65 and older are significantly more likely to develop the severe form of the disease than younger people. Those with weakened immune systems or chronic medical conditions are also vulnerable. Anyone living in or traveling to an affected area can be infected. Since the virus was first detected in New York in 1999, cases have been reported in every state in the continental United States.

There is no vaccine for the general public. There is no specific antiviral drug. Prevention is the only tool available. The CDC recommends EPA-registered insect repellents, long sleeves and pants when mosquitoes are active, and intact window and door screens. It also urges people to eliminate standing water around their homes—flower pots, buckets, bird baths, pet dishes, clogged gutters—anywhere mosquitoes can lay eggs and larvae can develop. These are small actions, but they are the primary defense.

Geography and climate shape where the virus takes hold. Warm temperatures accelerate mosquito reproduction and viral replication. Areas with abundant mosquito habitat, favorable weather, and large bird populations see sustained activity. The Midwest, Mid-Atlantic, and Northeast have reported fewer cases so far, and Alaska and Hawaii have none. But the CDC cautions that absence of reported cases does not mean absence of risk. Mild infections often go unreported. Surveillance varies by jurisdiction. The virus is circulating in places where people have not yet fallen ill.