West Nile Virus Management

Mosquito DUNKS available to control West Nile Virus

Mosquito DUNKS available to control West Nile VirusThe Township, through an Oakland County Health Division Program, is offering Mosquito DUNKS for the biological control of mosquito populations which may transmit West Nile Virus. DUNKS are doughnut shaped and each DUNK treats up to 100 square feet of standing water for a period of 30 days. Visit the Clerk’s office or the Public Services Building for more information.

Frequently Asked Questions

What is West Nile Virus (WNV)?

West Nile Virus is classified as an emerging infectious disease that is spread by a mosquito-borne virus. Historically found in Africa, Asia and the Middle East, the first cases of WNV within the United States occurred in the New York City area in 1991. Since that time, WNV has been detected in birds and mosquitoes in Michigan (2001) and human cases were confirmed in 2002 and every year there after. The virus has since spread across the United States to the Pacific Ocean, into several Canadian Provinces and Mexico. The continued expansion of the WNV indicates that it has been permanently established in the Western Hemisphere.

West Nile Virus is classified as an emerging infectious disease that is spread by a mosquito-borne virus.Is the West Nile Virus in Oakland County?

This chart depicts the WNV activities in Oakland County for the past few years. Federal, state, and local officials continue to closely monitor the distribution of WNV cases within the United States.

Table 1: WNV Case Total Comparison

  2005 2006 2007 2008 2009 2010 2011 2012
Oakland County

5

4

13 0 0 5 2 28
Michigan

62

55

17 17 1 29 34 249
United States

2,949

4,256

3,630 1,370 720 1,021 712 5,387

Table 2: WNV Death Total Comparison

  2005 2006 2007 2008 2009 2010 2011 2012
Oakland County

0

0

0 0 0 0 0 0
Michigan

4

7

4 0 0 3 2 15
United States

116

165

124 37 32 57 43 243

What is Bloomfield Township doing about West Nile Virus?

Bloomfield Township has been proactively working to protect our residents against the WNV since 2003. Currently, the Township West Nile Virus Management Program addresses the WNV problem through an integrated pest management program that consists of identifying and prioritizing approximately 1900 breeding sites (e.g. catch basins), then sampling and treating those public areas of the Bloomfield Township found to be high priority. 

The most important step in controlling the virus is to prevent the mosquitoes from becoming adults. In order to kill the pre-adult larvae, we treat prioritized catch basins, which have been identified as the principle breeding sites for mosquitoes in urban and suburban environments, with a natural insecticide called Bacillus sphaericus (BS).  BS, known by the trade name Vectolex, only affects mosquito and black fly larvae. It is approved by the EPA and has been shown to be highly effective in killing mosquito larvae.  The Township program begins in June and continues through late September to early October, depending on weather conditions. 

It is not likely that the wetlands in the Township, which are natural environments, will breed large numbers of mosquitoes.  These natural environments contain not only mosquito larvae, but also their predators, who are more than happy to eat a mosquito lunch!   

Additionally, mosquitoes need very specific requirements to breed: wetlands seldom meet these requirements.  The most common mosquito in Michigan to be associated with WNV is the Culex species.  Culex mosquitoes prefer still, temporary water sources and containers typically found around man-made structures.  Remember to regularly inspect all containers in your yard for standing water and dump the water out.

Public education and community outreach activities include Township newsletter articles, printed materials, website updates and cable programs. This information highlights the modes of virus transmission; means of prevention; and how to reduce the risk of exposure.

How is the West Nile Virus spread?

WNV is spread to humans by the bite of an infected mosquito.  The transmission cycle below illustrates that a bird becomes infected after being bitten by a mosquito carrying the virus. Several suspected mosquito species are involved in the transmission of WNV.  Horses and other animals bitten by infected mosquitoes can also become infected.  A human or horse that has the disease cannot spread the virus. 

Whenever mosquitoes are active there is a risk of getting WNV, therefore the highest probability of acquiring the virus exists during the months from late July through September. Although a vaccine is available for horses, there is currently no vaccine for humans.

West Nile Virus Transmission Cycle

* Graphic courtesy of the CDC

What are the signs of West Nile virus?

Most people (80%) who become infected with the West Nile virus suffer little more than flu-like symptoms or suffer no symptoms at all. Approximately 20% of those infected may develop West Nile fever, which may include the following symptoms: fever, headaches, swollen lymph gland, muscle weakness, body aches and skin rash. A very small percentage of severe cases may experience headaches, high fever, stiff neck, confusion, coma, tremors, paralysis and death. The risk of severe illness is highest for people over 50 years of age.

What can we do to avoid contracting West Nile virus?

It’s important to remember that YOU are the most important first line of defense in protecting yourself from and preventing the spread of WNV. You can minimize your contact with mosquitoes by following these three actions:

1. REDUCE AREAS WHERE MOSQUITOES BREED

Without proper areas to breed, mosquitoes cannot lay their eggs. Throughout the season empty standing water from containers, such as, flowerpots, buckets, toys, pet bowls, clogged rain gutters, boats and discarded tires.  Wash birdbaths on a weekly basis to prevent the build-up of algae and dead leaves.  Keep swimming pools clean and chlorinated and drain water that collects on top of pool covers.  Drain unused pools. Aerate ornamental pools or stock them with surface feeding minnows.  Mow your lawn on a regular basis, cutting tall grass and weeds next to foundations and fence lines.

2. REPEL AGAINST MOSQUITOES

Maintain window and door screening to keep mosquitoes out of buildings. Always wear long sleeved shirts, pants and socks outdoors, particularly from dusk to dawn. Avoid shaded and wooded areas where mosquitoes may be present. Follow the Centers of Disease Control and Prevention (CDC) current recommendations for using insect repellent containing DEET, especially on infants and young children.

3. REPORT POTENTIAL MOSQUITO BREEDING SITES AND DEAD BIRDS

A connection had been made between an outbreak of human WNV infection and disease in birds. Please report any dead birds and potential mosquito breeding areas to the Engineering and Environmental Department by calling 248.594.2800.

When calling to report a dead bird, please leave your phone number, state the species of bird (if known), and an address or location of where the bird was found. This data is relayed monthly to the Oakland County Health Department in order to monitor the incidence of WNV. While there is no evidence that a person can get the virus from handling live or dead infected birds, a person should avoid barehanded contact when handling any dead animal. Please use gloves and double plastic bags when handling the bird, then place in your trash container.

Additional Information

This document is available to view in PDF format. These documents are available in PDF format.

2012 Michigan West Nile Virus Surveillance Report
Bloomfield Township's West Nile Virus Management and Mosquito Smarts Brochure
Mosquito Smarts: Cat & Dogs Fact Sheet
Mosquito Smarts: Horses
Friends of the Rouge Brochure

For more information on how you can protect yourself against the West Nile Virus, please visit the following website links below:

Centers for Disease Control
Michigan Department of Agriculture
Michigan Mosquito Control Association
Oakland County Health Division

Updated March 2013