West Nile virus cases, Butte County
13 human West Nile virus cases reported in Butte County in 2026 so far. 53 in the worst year on record here (2015).
Human West Nile virus cases reported to the California Department of Public Health for Butte County, by year, with the statewide total for scale.
Up to dateUpdated (18 h ago)Refreshed every few days (CDPH updates weekly in season)Source
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13human West Nile virus cases reported in Butte County in 2026 so far
53in the worst year on record here (2015)
278cases since 2006
3%of California's 2026 cases were in Butte County
The records
| Year | Human cases, Butte | Human cases, California | Butte share of state | First case week | Last case week |
|---|---|---|---|---|---|
| 2026 | 13 | 378 | 3.4% | 30 | 37 |
| 2025 | 4 | 117 | 3.4% | 33 | 42 |
| 2024 | 11 | 132 | 8.3% | 32 | 38 |
| 2023 | 18 | 433 | 4.2% | 32 | 41 |
| 2022 | 3 | 209 | 1.4% | 32 | 36 |
| 2021 | 13 | 127 | 10% | 31 | 39 |
| 2020 | 4 | 235 | 1.7% | 35 | 35 |
| 2019 | 5 | 225 | 2.2% | 33 | 40 |
| 2018 | 12 | 217 | 5.5% | 30 | 53 |
| 2017 | 4 | 553 | 0.7% | 33 | 53 |
| 2016 | 21 | 442 | 4.8% | 33 | 40 |
| 2015 | 53 | 782 | 6.8% | 30 | 43 |
| 2014 | 24 | 801 | 3% | 30 | 49 |
| 2013 | 24 | 379 | 6.3% | 32 | 53 |
| 2012 | 10 | 479 | 2.1% | 33 | 41 |
| 2011 | 3 | 158 | 1.9% | 35 | 40 |
| 2010 | 1 | 111 | 0.9% | 33 | 33 |
| 2009 | 2 | 112 | 1.8% | 36 | 41 |
| 2008 | 6 | 445 | 1.3% | 32 | 50 |
| 2007 | 16 | 380 | 4.2% | 30 | 37 |
| 2006 | 31 | 272 | 11% | 33 | 43 |
Weeks are CDC reporting weeks (1 to 53). Counts only confirmed human cases; infected birds, mosquitoes and horses are tracked separately at westnile.ca.gov.