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West Nile virus is a disease that is transmitted to humans by mosquitoes. The symptoms of West Nile range from none to very serious.


Weekly Vector Index

Updated Thursdays

The City of Fort Collins has four separate zones for adulticiding (spraying). Before any spraying is considered, the vector index must be 0.75 in a zone and there must be more than one human case of West Nile in a week.

Zone 1 = 0.094
Zone 2 = 0.0
Zone 3 = 0.0
Zone 4 =0.095

Week 23 Data – June 6, 2014 (PDF 251KB)
Week 24 Data – June 12, 2014 (PDF 64KB)
Week 25 Data – June 19, 2014 (PDF 37KB)
Week 26 Data – June 26, 2014 (PDF 44KB)
Week 27 Data – July 3, 2014 (PDF 45KB)
Week 28 Data – July 11, 2014 (PDF 328KB)
Week 29 Data – July 19, 2014 (PDF 92KB)
Week 30 Data – July 24, 2014 (PDF 92KB)
Week 31 Data – August 1, 2014 (PDF 93KB)
Week 32 Data – August 8, 2014 (PDF 329KB)
Week 33 Data – August 18, 2014 (PDF 329KB)
Week 34 Data – August 22, 2014 (PDF 94KB)
Week 35 Data – September 2, 2014 (PDF 94KB)

Weekly Trap Data Reports

June 6, 2014 (582 KB) June 12, 2014 (527 KB) June 19, 2014 (444 KB) June 26, 2014 (570 KB) July 3, 2014 (614 KB) July 11, 2014 (521 KB) July 19, 2014 (604 KB) July 24, 2014 (611 KB) August 1, 2014 (385 KB) August 7, 2014 (612 KB) August 14, 2014 (606 KB) August 22, 2014 (604 KB) September 2, 2014 (604 KB)

Human Cases

Weekly number of human cases in Fort Collins to date – 2

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Businesses Can Apply to Opt Out of Spraying

If you are a business or laboratory you can apply to opt out of our adulticiding (spraying operations). Please keep in mind only commercial businesses able to prove a long-term negative financial impact to their business will be considered. To apply, enter your business and contact information. Applicants will receive an application via email with the requirements and details of the opt-out.

Apply here.

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New Interactive Mosquito Surveillance & Control Map

Our mosquito contractor, Colorado Mosquito Control, has a NEW interactive mosquito surveillance and control map.

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¿Habla Español?

Protéjase de picaduras de mosquitos y del virus Nilo Occidental este verano. En esta página, usted encontrará consejos, recursos y boletines de publicación inmediata que le ayudara a mantenerse informado.


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West Nile Notify: Subscribe to Receive Spraying Notifications

The City of Fort Collins developed a system, West Nile Notify, to send out emails in advance of our spraying operations. Simply subscribe by adding your email to our list. West Nile Notify allows citizens to be notified as early as possible to scheduled mosquito adulticiding. This service is free of charge and subscribers can choose to receive notifications on any or all of the six spraying areas. If you do not have an email address, please call the Colorado Mosquito Control at 970-962-2582.

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Protect Yourself with the Four D's!

1. Drain
Mosquitoes breed in water! Drain any standing water in your yard each week. Bird baths, clogged gutters and kiddie pools are common breeding sites.

2. Dress
Wear lightweight, long-sleeved shirts and long pants while outdoors. Spray clothing with insect repellent since mosquitoes may bite through clothing.

Apply insect repellent sparingly to exposed skin. Use an approved repellent according to its label. Find the repellent that is right for you.

4. Dawn/Dusk
Limit time spent outdoors at dawn or dusk, when mosquitoes are most active and feeding. 

Find out more!

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West Nile Virus Technical Advisory Committee

The West Nile Virus Technical Advisory Committee meets to discuss the previous mosquito season and considers recommendations for future response guidelines. The committee is composed of City-appointed experts who provide technical expertise and make recommendations to City Council regarding the City’s West Nile Virus Management Policy. Visit their webpage for meeting minutes and to get notifications when new minutes are available.

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Mosquito Dashboard

Keep tabs on mosquitoes in your neighborhood with the mosquito dashboard. Select the date and location, and the dashboard will give you numbers of trapped mosquitoes, and whether or not any tested positive for West Nile virus.