Phoenix-area health officials report year’s 1st death related to mosquito-borne West Nile virus

Phoenix-area health officials reported the year’s first death related to the West Nile virus on Tuesday.

The Maricopa County Department of Public Health described the deceased person as an older adult with underlying health conditions.

West Nile virus is spread through mosquito bites, although most people who get it don’t get ill.

However, about 20% of infections result in flu-like symptoms, while about 1 in 150 can result in severe complications, including encephalitis or meningitis.

Older individuals with weakened immune systems are at a higher risk for complications.

“This case is a tragic reminder that West Nile virus can cause severe illness and even death,” said Melissa Kretschmer, epidemiology supervisor for the county’s Vector-Borne and Zoonotic Diseases program. “As mosquito activity increases across Maricopa County, we encourage residents to take prevention seriously by using insect repellent, eliminating standing water around their homes, and protecting themselves from mosquito bites whenever they spend time outdoors.”

West Nile virus seen in Maricopa County more this year than last

Maricopa County has confirmed 17 cases of West Nile virus in humans so far this year, over four times as many as were documented in the Valley over the same period in 2025.

Mosquitos that spread the disease can proliferate in standing water, even small amounts, health officials warned.

“Even an overturned bottle cap can hold enough water for mosquitoes to breed,” Kretschmer said. “It’s important that we remove these breeding sources that can form after rain or watering plants.”

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