Department of Medicine

It’s West Nile Virus Season Again. How Worried Should We Be?

Written by Mark Harden | August 27, 2024

In Colorado, 2023 was a bad year for West Nile virus. And while the state’s annual summer-and-fall outbreak of the mosquito-borne infection so far seems less severe this year, West Nile continues to spark concern and questions.

Last year, out of 634 people in Colorado who tested positive for West Nile virus infection, 386 people were hospitalized, and 51 died, according to state Department of Public Health & Environment data. It was the highest West Nile death toll in the state since 2003, which was a year after cases were first reported in the state.

This year, as of Aug. 14, 13 cases had been reported in Colorado, with seven hospitalizations and no deaths up to that point. On Aug. 16, Denver public-health officials confirmed the year’s first case in the city, and Boulder County announced its first case Aug. 20. It’s believed that thousands of Coloradans infected with West Nile virus never get tested because they experience no symptoms or only mild ones.

Even the nation’s former top government infectious disease expert has been impacted by West Nile virus. Anthony Fauci, MD, was hospitalized recently after being infected and was recovering at home, news media reported Aug. 24.

To learn more about West Nile virus in Colorado, the threat it poses, and what we can do to protect ourselves, we turned to Lakshmi Chauhan, MD, assistant professor in the University of Colorado Department of Medicine’s CU Division of Infectious Diseases. Chauhan practices in the infectious disease clinic at UCHealth University of Colorado Hospital, and is among 21 faculty members in the inaugural class of the department’s Clinical Excellence Society.

Photo at top courtesy U.S. Centers for Disease Control and Prevention.