HomeMy WebLinkAboutMemo - Mail Packet - 08/27/2024 - Memorandum from Ryan Vincent re: West Nile Virus (WNV) – Weekly UpdateNatural 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
MEMORANDUM
Date: August 19, 2024
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) – Weekly Update
KEY POINTS
• Based on this week’s data, the Larimer County Department of Health and
Environment (LCDHE) does not recommend spraying for adult mosquitos at this
time.
• While data shows a reduction in WNV across the city, it should be noted that
amplification of the virus can continue into September and there are still five weeks
remaining in the season. In addition, recent storms, coupled with a seven- to ten-day
mosquito incubation period, may increase WNV in the coming weeks.
CURRENT VECTOR INDEX INFORMATION
Week 33 of 38 VI Threshold: Previous Week VI: Current VI:
FC – Zone NW NA 0.33 0.00
FC – Zone NE NA 0.12 0.09
FC – Zone SE NA 0.07 0.01
FC – Zone SW NA 0.00 0.00
FC – Citywide NA 0.13 0.02
Floating Zone 0.75 0.73 0.35
Docusign Envelope ID: 69433FD0-510A-419F-B1F0-1A2C215915CD
CURRENT VECTOR INDEX INFORMATION CONTINUED
The 5-trap floating zone with the highest vector index (0.35) was located between Mulberry
Street and Drake Road, and between College Avenue and I-25. The policy threshold for
spraying is 0.75.
CURRENT CONDITIONS
Three WNV-positive traps were detected in the City’s trapping network. Two positive traps were
in the NE quadrant and one in the SE.
VDCI (Vector Disease Control, International) supplied a monthly report for July that includes
information about weather, mosquito population surveillance, and larval control operations. The
report is posted at fcgov.com/westnile/local-data. Key takeaways include:
• Temps were one to two degrees Fahrenheit above normal throughout the County.
• Precipitation remains at 43% of normal for the season (April 1 to July 31.)
• Total culex mosquitos caught and tested decreased by 84% from 2024 levels.
• VDCI staff performed 2,257 site inspections and released larvicide at 840 locations.
ADDITIONAL INFORMATION
• LCDHE has confirmed two human cases of WNV and continues to monitor potential new
cases. For contrast, in 2023, there were 29 confirmed cases at this time. Historically,
LCDHE receives the most WNV case reports in August. State health officials report 13
cases as of Aug. 14.
• Citywide public outreach is ongoing and includes social media posts, utility bill inserts,
and other advertising. Outreach information is centered on the “4Ds” messaging, which
encourages people to Drain standing water, Dress in long pants and sleeves to deter
biting, Defend with EPA-approved repellant, and avoid the high mosquito activity time
between Dusk & Dawn. Messaging also encourages community members to opt in to
receive notification about any future spray events.
• City staff, VDCI, and Colorado State University continue to implement preventative WNV
management actions such as larval treatments, trapping, and testing.
• VDCI did not spray any HOAs last week. As of Aug. 19, they do not have plans to treat
any Fort Collins HOAs this week.
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Docusign Envelope ID: 69433FD0-510A-419F-B1F0-1A2C215915CD