West Nile Discovered in Lexington Mosquito Pool

The Massachusetts Department of Public Health (MDPH) announced this week that West Nile virus (WNV) has been detected in mosquitoes collected from Lexington, Belmont, Waltham, Framingham, Boston and Arlington.

WNV is most commonly transmitted to humans by the bite of a mosquito infected with the virus. While WNV can infect people of all ages, people over the age of 50 are at higher risk for severe infection.

Culex mosquitoes are the primary vectors or carriers of West Nile Virus. The mosquitoes that carry this virus are common throughout the state, and are found in urban as well as more rural areas. Culex mosquitoes need shallow stagnant water to reproduce. While most mosquito species develop in wetlands, Culex mosquitoes prefer urban environments to lay their eggs in nutrient rich stagnant water found in catchbasins, clogged rain gutters, unused tires, buckets and other water holding containers.

While the Lexington Health Division continues to work closely with the MDPH, locally we are continuing to work with the Eastern Middlesex Mosquito Control Program in larvaciding catch basins and investigating sources of potential breeding grounds.

Because of the role of Culex mosquitoes transmitting West Nile Virus, residents can help combat this disease by mosquito proofing their property.  Limit the number of places around your home for mosquitoes to develop by either draining or getting rid of items that hold water. Check rain gutters and drains, empty any unused flowerpots and wading pools, and change water in birdbaths frequently. Install or Repair Screens - Some mosquitoes like to come indoors. Keep them outside by having tightly-fitting screens on all of your windows and doors. By taking a few, common-sense precautions, people can help to protect themselves and their loved ones:

Avoid Mosquito Bites

Be Aware of Peak Mosquito Hours - The hours from dusk to dawn are peak biting times for many mosquitoes. Consider rescheduling outdoor activities that occur during evening or early morning. Otherwise, take extra care to use repellent and protective clothing.

Clothing Can Help reduce mosquito bites. Although it may be difficult to do when it’s hot, wearing long-sleeves, long pants and socks when outdoors will help keep mosquitoes away from your skin.

Apply Insect Repellent when you go outdoors.

Use a repellent with DEET (N, N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), IR3535 or oil of lemon eucalyptus [p-methane 3, 8-diol (PMD)] according to the instructions on the product label.  DEET products should not be used on infants under two months of age and should be used in concentrations of 30% or less on older children.  Oil of lemon eucalyptus should not be used on children under three years of age.  Permethrin products are intended for use on items such as clothing, shoes, bed nets and camping gear and should not be applied to skin. 

Mosquito-Proof Your Home

Drain Standing Water - Mosquitoes lay their eggs in standing water. Limit the number of places around your home for mosquitoes to breed by either draining or getting rid of items that hold water. Check rain gutters and drains. Empty any unused flowerpots and wading pools, and change water in birdbaths frequently. 

Install or Repair Screens - Some mosquitoes like to come indoors. Keep them outside by having tightly-fitting screens on all of your windows and doors.

The majority of people who are infected with WNV (approximately 80%) will have no symptoms at all. Approximately 20% of those infected will have symptoms such as fever, headache, body aches, nausea, vomiting, and sometimes swollen lymph glands or skin rash. Less than 1% of people infected with WNV will develop severe illness, including encephalitis or meningitis as demonstrated by high fever, headache, neck stiffness, disorientation and muscle weakness. If you notice any of these symptoms in yourself or a loved one, contact your healthcare provider immediately.

Information about WNV and reports of WNV activity in Massachusetts during 2012 can be found on the MDPH website at http://www.mass.gov/dph/wnv. Recorded information about WNV is also available by calling the MDPH Public Health Information Line at 1-866-MASS-WNV (1-866-627-7968). Facts sheets on WNV and other mosquito-related materials are available at the Office of Community Development, Health Division, 1625 Massachusetts Avenue.  For more information please contact the Office of Community Development, Health Division, Gerard Cody, Health Director at 781-862-0500 x 237 or gcody@lexingtonma.gov.