HomeMy WebLinkAboutMemo - Mail Packet - 7/18/2023 - Memorandum From Matt Parker And Amy Resseguie Re: West Nile Virus (Wnv) – Weekly Update 1745 Hoffman Mill Road
PO Box 580, Fort Collins, CO 80522-0580
MEMORANDUM
Date: July 11, 2023
To: Mayor and City Councilmembers
From: Matt Parker, Sr. Supervisor, Natural Areas
Amy Resseguie, Lead Specialist, Communications & Public Involvement
Through: Tyler Marr, Deputy City Manager
Dean Klingner, Director, Community Services
Mike Calhoon, Director, Parks
Katie Donahue, Director, Natural Areas
Subject: West Nile virus (WNV) – Weekly Update
Summary:
Culex spp. mosquitoes, capable of transmitting WNV, are exceedingly abundant this
week (week 27) when compared to historic averages for peak weeks (weeks 30-31). As
anticipated, WNV is increasing with one positive trap last week and three positive traps this
week. Exceptionally high abundance values, and seasonal disease amplification will likely
prompt higher Vector Index values in the very near term. The data is very likely to cross the
policy threshold, indicating an adult mosquito treatment, within the next two weeks.
Current Vector Index:
Week No: 27 Vector Index
Threshold:
Previous Week Vector
Index:
Current Vector
Index:
FC – Zone NW NA 0.00 0.00
FC – Zone NE NA 0.00 0.00
FC – Zone SE NA 0.07 0.27
FC – Zone SW NA 0.00 0.00
FC – Citywide NA 0.02 0.09
Floating Zone 0.75 0.00 0.40
Current Conditions: Three traps detected WNV-positive mosquitoes, all in the southeastern
quadrant. A floating zone consisting of 5 traps in the southeastern quadrant indicates a vector
index value of 0.40, below the City policy threshold of 0.75.
The Centers for Disease Control (CDC) track weeks numerically throughout the year to allow for
quick year-to-year comparison. The active WNV season runs from week 23 through week 37,
this current week being week 27. This week’s abundance data exceeds the historic average
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City of Fort Collins
peak, which occurs during weeks 30 and 31. The current abundance values for Culex. spp.
mosquitoes in the southeastern quadrant of the city is nearly 8x higher than average, and nearly
5x higher citywide. Exceptionally hot and dry weather this week, coupled with ample ephemeral
breeding pools, will likely accelerate mosquito development in the coming weeks.
Additional Information:
Three homeowners associations have privately contracted with area pest control
companies to spray within the areas of Greenstone, Lindenwood, and Willow Springs.
Both the City of Loveland and the Town of Berthoud are experiencing historically high
levels of mosquito populations as well.
Process for Spray Recommendations: When the City’s trapping network shows WNV activity
beyond the threshold of 0.75, the Larimer County Department of Health and Environment
(LCDHE) makes a recommendation that the City conduct an application to treat adult
mosquitoes. When an application is recommended, areas of concern will be identified based on
data from a minimum of 5 traps. Identified treatment areas may be sub-zone or may cross zone
boundaries.
Outreach and Public Awareness:
Last week the LCDHE issued a press release notifying the public of excessive Culex spp.
populations and the detection of WNV-positive mosquitoes. Public outreach is underway
including social media posts, utility bill inserts and other advertising. Outreach information is
centered on “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.
If the LCDHE makes a recommendation to spray in future weeks, additional communication will
take place, including phone, email and text notifications sent to those who have signed up to
receive such notices. Spray notifications and other outreach materials are shared in both
English and Spanish.
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