Federal surveillance now puts the 2026 West Nile virus season at 143 human cases nationally, according to ArboNET data posted by the Centers for Disease Control and Prevention with figures current through Aug. 4. That is up from 113 cases reported one week earlier, and it lands as the country moves into the stretch of summer when West Nile transmission has historically been heaviest.
The rate of accumulation is what public health officials are watching. The Johns Hopkins Bloomberg School of Public Health noted this month that in 2003, the year of the largest West Nile outbreak recorded in the United States, only 44 cases had been reported nationally by July 30. That season went on to produce 9,862 cases and 264 deaths. By July 28 of this year, the count stood at 113, roughly two and a half times the 2003 figure at a comparable point.
