West Nile Virus Causes Deaths Throughout Europe and the USA

The leading mosquito-borne disease in the United States is not Chikungunya or Dengue; it's the seldom-discussed West Nile Virus (WNV).

Now found in 45 states, WNV causes more illnesses and deaths than any other mosquito-borne disease in the continental U.S., says the U.S. CDC.

As of December 17, 2025, the CDC reported over 2,000 individuals infected with WNV this year. Colorado is an unfortunate leader with 284 cases. Texas has reported 4 WNV-related deaths.

And 1,404 WNV-related Neuroinvasive disease cases in 2025

AMA infectious diseases director Erica Kaufman West, MD, recently addressed the ongoing risks of WNV in the USA. =

A study published by the JAMA Network Open (Vol. 8, No. 12) concluded that older people with a history of chronic kidney disease or conditions affecting blood flow to the brain have about double the risk for developing neuroinvasive disease that can lead to paralysis and death following WNV infection.

"In 2025, there's been a substantial increase in West Nile virus activity with 41% more severe-disease cases and 32% more deaths than what is typically seen," Dr. Kaufman West said in a press release on December 5, 2025.

Physicians don't always have WNV on their radar in patients at high risk for infectious disease—but they should, the AMA added.

And in Europe, 14 countries have reported a total of 1,112 locally acquired human cases.

The countries with the highest number of WNV cases include Italy (779 cases, 72 deaths), Greece (96), and France (62), followed by Serbia (62), Romania (49), and Spain (36). Other countries reporting cases are Hungary (14), Croatia (4), Albania (3), and Germany (2), along with North Macedonia (2), Bulgaria, Kosovo, and Türkiye.

Unfortunately, there have been 97 reported deaths due to the virus in Europe in 2025.

According to the European CDC, these figures are lower than those seen in 2018, 2022, and 2024, years when virus circulation was particularly intense. Italy's data in 2025 represents the highest number of human WNV cases ever reported in a single year. 

Both the CDC and ECDC say there is no licensed WNV vaccine for humans yet.

However, several candidates are in clinical trials, focusing on technologies such as live-attenuated or DNA-based vaccines. Therefore, personal protection is the primary human prevention tactic.

While human vaccines are pending, effective equine vaccines are available and widely used, alongside mosquito control.