HomeMy WebLinkAboutMemo - Mail Packet - 07/01/2025 - Memorandum from Ryan Vincent re West Nile Virus – Weekly ReportNatural Areas Department
1745 Hoffman Mill Road
PO Box 580, Fort Collins, CO 80522
970-416-2493
rvincent@fcgov.com
CC: Mike Calhoon, Parks Director; Katie Donahue, Natural Areas Director; Matt Parker, Natural Areas Ecological
Stewardship Manager 1
MEMORANDUM
Date: June 24, 2025
To: Mayor and City Councilmembers
Through: Kelly DiMartino, City Manager
Tyler Marr, Deputy City Manager
Dean Klingner, Community Services Director
From: Ryan Vincent, Natural Areas Sr. Supervisor
Subject: West Nile Virus – Weekly Report
BOTTOM LINE
This information is intended to help City Council respond to community questions or concerns
about West Nile Virus (WNV) as they arise.
• WNV-positive mosquitos were detected in two traps this week, both in the SE quadrant
of the city.
• This is the earliest positive WNV detection seen since 2017.
• While vector indices (VIs) remain low, staff will be watching mosquito activity closely in
the coming weeks to determine the risk of WNV to the community.
WNV ACTIVITY ACROSS THE CITY
WNV Activity Across the City Week 25 of 37
VI Threshold for spraying in a five-trap floating zone is 0.75
Zone Previous Week VI Current VI Number of Positive Traps
NW 0.00 0.00 0
NE 0.00 0.00 0
SE 0.00 0.12 2
SW 0.00 0.00 0
Citywide 0.00 0.04 0
Floating Zone 0.00 0.50 2
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2
IS SPRAYING RECOMMENDED THIS WEEK?
No. The Larimer County Department of Health and Environment (LCDHE) may recommend
spraying for adult mosquitoes only when the vector index exceeds 0.75 in at least five adjacent
traps (or a floating zone) within the City’s 53-trap network.
The vector index (VI) is a calculation of the abundance of the two species capable of
transmitting WNV and the rate of WNV infection within those mosquitoes.
If LCDHE recommends spraying, City staff will coordinate the operation in the floating zone. The
City will notify the community through email, text alerts and other communication channels.
Residents can sign up for alerts at nocoalert.org or by texting WNV to 888-777.
NEXT STEPS
• Vector Disease International, the City’s contractor, is actively monitoring mosquito
breeding sites and treating larvae when appropriate.
• LCDHE will track vector indices weekly and recommend adult mosquito spraying if
needed.
• City staff will continue sharing updates with the community through fcgov.com/westnile
and social media.
• Staff will share West Nile Virus reports with Council to highlight trends and provide
advance notice of any planned mosquito spraying.
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