HomeMy WebLinkAboutMemo - Read Before Packet - 08/26/2025 - Memorandum from Ryan Vincent re: West Nile Virus (WNV) – Spray NotificationNatural Areas Department
1745 Hoffman Mill Road
PO Box 580, Fort Collins, CO 80522
970-416-2493
rvincent@fcgov.com
CC: Dean Klingner, Community Services Director; Mike Calhoon, Parks Director; Katie Donahue, Natural Areas
Director; Matt Parker, Natural Areas Ecological Stewardship Manager 1 of 2
MEMORANDUM
Date: August 26, 2025
To: Mayor and City Councilmembers
Through: Kelly DiMartino, City Manager
Tyler Marr, Deputy City Manager
From: Ryan Vincent, Natural Areas Sr. Supervisor
Subject: West Nile Virus (WNV) - Spray Notification
BOTTOM LINE
The Larimer County Department of Health and
Environment (LCDHE) recommends adult mosquito
treatment for both city and county areas on
Thursday, Aug. 28, weather permitting. The
backup date is Sunday, Aug. 31.
The treatment zone extends from Shields Street to
I-25 between Douglas Road and Mulberry Street,
and from I-25 to County Road 5 between Vine
Drive and Mulberry Street. This area of the city has
not been sprayed this year.
The vector index (VI) in this area is 1.04, which
exceeds the City’s policy threshold of 0.75.
On Aug. 24, LCDHE reported the first local death
related to WNV. As of Aug. 20, the Colorado
Department of Public Health and Environment
reported three deaths and 69 cases statewide. In
Larimer County, cases increased from 6 to 20 in the past two weeks.
Docusign Envelope ID: 1F4D4114-4D1F-468F-9EF8-3BF28F16D970
2 of 2
WNV ACTIVITY ACROSS THE CITY
Week 34 of 37
Quadrant Previous Week VI Current VI Previous Week
Positive Traps
Current Week
Positive Traps
NW 0.54 0.47 4 5
NE 0.00 0.57 0 5
SE 0.49 0.26 7 4
SW 0.68 0.46 4 4
Citywide 0.42 0.42 15 18
Floating Zone NA* 1.04** NA* 5*
*Floating zones vary in size and location and cannot be compared from week to week.**VI Threshold for spraying in a floating zone is 0.75.
WNV ACTIVITY COMPARED TO HISTORICAL AVERAGES
Abundance of Culex mosquitoes (the carriers of WNV) remains below average. However, the
much higher-than-normal infection rate is elevating the vector index. Historically, the infection
rate peaks next week (week 35).
OUTREACH EFFORTS TO INFORM RESIDENTS
• The City will share spray information on fcgov.com/westnile and its social media
accounts. Community members who signed up for NOCO Alert will also receive
notifications. LCDHE will communicate directly with neighborhoods in the spray zone
that are outside Fort Collins city limits.
• Community members can track the progress of spray vehicles in real time using GPS on
the City’s WNV website.
NEXT STEPS
City staff will coordinate with Vector Disease Control International, the City’s contractor, to carry
out spraying on Thursday, Aug. 28, weather permitting, with Sunday, Aug. 31, as the backup
date. Spraying will begin at dusk.
Docusign Envelope ID: 1F4D4114-4D1F-468F-9EF8-3BF28F16D970
August 25, 2025
Contact: Kori Wilford
Kwilford@larimer.org
FOR IMMEDIATE RELEASE
First West Nile Virus Death of a Larimer County Resident This Year
Larimer County, Colorado – The Larimer County Department of Health and Environment
(LCDHE) is reporting the first West Nile virus (WNV) death of a Larimer County resident this
year. The Fort Collins adult passed away from neuroinvasive WNV.
“We are saddened by this loss and extend our deepest condolences to this resident’s loved
ones,” says Tom Gonzales, Larimer County Public Health Director. “This death underscores the
potentially serious nature of West Nile virus.”
So far this year, there have been 20 confirmed cases of WNV in Larimer County, with ages
ranging from 24 to 86.
West Nile virus is most commonly spread to people by the bite of an infected mosquito.
Symptoms typically appear three to 14 days after being bitten and may include fever, severe
fatigue, headache, body aches, skin rash and swollen lymph nodes. While most people infected
with West Nile virus don’t have symptoms, some can develop a serious, potentially deadly
illness. People aged 55 years and older and those with certain medical conditions are at greater
risk of serious illness. Talk with a health care provider if you develop a fever with severe
headaches or confusion.
“Even as the weather gets cooler and we start seeing fewer mosquitoes, trap data still show that
mosquitoes in Larimer County are carrying the virus,” adds Gonzales. “We continue to urge
everyone to take precautions. It's crucial to protect yourselves and your families.”
The Health Department urges all residents to adopt effective protective measures to prevent
mosquito bites:
● Regularly use an EPA-registered insect repellent.
● Wear loose-fitting long-sleeved shirts and pants for long walks, gardening, and other
times outside.
● Avoid outdoor activities during peak biting times around dawn and dusk.
The Larimer County Department of Health and Environment closely monitors West Nile virus
prevalence in the community through partnerships with municipalities, a mosquito abatement
company, and Colorado State University to assess the risk to Larimer County residents.
To learn more about West Nile virus and how to protect yourself, visit: www.larimer.gov/westnile.
Docusign Envelope ID: 1F4D4114-4D1F-468F-9EF8-3BF28F16D970
###
Docusign Envelope ID: 1F4D4114-4D1F-468F-9EF8-3BF28F16D970