West Nile Virus & Mosquito Surveillance Data

Vector-Borne Disease

Public Health

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What you need to know

The first case of West Nile Virus in Nebraska was reported in 2002.

In 2024, there were 92 clinical cases of West Nile Virus reported in Nebraska. 50 were neuroinvasive and 42 were non-neuroinvasive. This was a decrease from the 150 clinical cases reported in 2023 (91 neuroinvasive, 56 non-neuroinvasive).

It is important to note that for every neuroinvasive case of West Nile Virus, there is an estimated 30-70 non-neuroinvasive cases so the number of total cases in the state is likely much higher.

The DHHS West Nile Virus Surveillance Program works to identify and prevent West Nile virus in Nebraska by

Trapping and testing mosquitoes
Collect reports of dead birds
Investigating suspected human WNV cases.

The Nebraska Department of Agriculture investigates possible cases involving horses. For all suspected human cases, the DHHS and the local public health departments conduct investigations.

Mosquito-borne Disease Weekly Report

A weekly summary of Nebraska mosquito-borne disease surveillance.

2025 West Nile Virus Data

Humans

Category	Number	Maps
Clinical Positive Individuals	25	Human Clinical
Positive Blood Donors	6	Positive Blood Donors
Cumulative Number of Clinical Cases and Blood Donors	31

*Data suppressed due to low numbers (1-5 cases)

2025 Human Clinical Specifics

Age Range	Number
0-13	0
14-25	*
26-50	9
51-64	*
65+	10
Gender
Male	13
Female	12
Diagnosis
WNV Neuroinvasive	11
WNV Non-Neuroinvasive	14
Hospitalized	12
Deaths	0

*Data suppressed due to low numbers (1-5 cases)

Animals

Surveillance Type	Number Tested	Number Positives	Maps
Mosquito Pools Routine Surveillance (West Nile Virus, St. Louis Encephalitis Virus, Western Equine Encephalitis Virus)	981	120 (WNV) 1 (SLE)	Interactive Mosquito Surveillance Maps
Mosquito Pools Enhanced Surveillance 2024 (Jamestown Canyon Virus, Cache Valley Virus, LaCrosse Encephalitis Virus)	541	3 (JCV) 1 (CVV)	Interactive Mosquito Surveillance Maps
Equines	N/A	1	Equine
Birds	N/A	0	Birds

Total Human WNV Cases in Nebraska 2012-2022

West Nile Virus 10 Yr Average Annual Human Case Rate — West Nile Virus 10 Year Average Annual Human Case Rate

Mosquito Surveillance Data

The Nebraska Department of Health and Human Services (NDHHS) in partnership with our local public health departments collects mosquitoes from across the state. These mosquitoes are then tested by the Nebraska Public Health Laboratory (NPHL) for the presence of arboviruses.

During the 2022 season, 992 mosquito pools* containing 14,381 Culex mosquitoes were tested. Of those pools tested, 88 positive WNV pools were detected. There was one positive St. Louis Encephalitis (SLE) virus mosquito pool detected from Dawson County.

In 2022, the first WNV positive pool was detected during trapping period 7 in Hall County. In 2021, the first WNV positive mosquito pool was identified during trapping period 5 in Scottsbluff County.

Starting in 2024, NDHHS began limited expanded surveillance and testing for additional pathogens found in mosquitoes. Pooled mosquito samples are tested by the Nebraska Public Health Lab for 3 additional viruses - Cache Valley virus (CVV), Jamestown Canyon virus (JCV), and LaCrosse Encephalitis virus (LACV).

*mosquitoes are tested in pools of up to 50 mosquitoes according to species, site location, and collection date