The warmer than normal temperatures that we’ve experienced this summer is likely increasing both the EEE and WNV risk. Nationally it appears as though the numbers of WNV human cases in 2012 will be among the highest numbers recorded in a single year. The basis of both the national WNV risk and the local WNV and EEE risk can be traced to a series of weather events beginning this past winter through this summer.

While we do have one positive mosquito pool in Wayland that tested positive for West Nile Virus, Wayland is still identified by the state as an area of low risk for mosquito-borne illness as of 8/16/12. To date the following virus information has occurred in our region: a EEE human case from the Metrowest area with a travel history to the Mid-Atlantic states, the recently reported WNV human case from Cambridge, the positive EEE finding in a mammal biting species (Cq. perturbans) from Reading, the positive EEE mosquito from a bird biting mosquito (Cs. melanura) from Sudbury and positive WNV isolations from Culex mosquitoes from Arlington, Belmont, Brookline, Everett, Framingham, Lexington, Malden, Medford, Melrose, Newton, Waltham and Wayland.

While recent rains may have flushed mosquitoes from some catch basins, they have also filled all the water holding containers that exist on residential and commercial properties. It’s likely that the Culex mosquito population will be increasing over the next few weeks and we’d like to remind residents to check their properties for water holding containers.

In Wayland, mosquitoes pose a health threat especially for West Nile Virus (WNV) between now and early October, or the first frost. Residents should be aware that mosquito-borne viruses such as WNV, or EEE could cause fever, meningitis or encephalitis. Early symptoms of these diseases include fever, headache, stiff neck and muscle weakness.

Mosquitoes acquire WNV or EEE after biting an infected bird. Those mosquitoes can then transmit that virus to a person, horse or to another bird. Culex mosquitoes that develop in water holding containers are the primary vectors of WNV, while the mosquitoes that transmit EEE originate in wetlands.

What you should do to avoid mosquito bites

• Be aware of peak mosquito hours- The hours from dusk to dawn are peak biting times for many mosquitoes. Mosquitoes are more active in damp, shady areas, during cloudy humid days, and at night. Consider rescheduling outdoor activities that occur during evening or early morning. Also, 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 (3-[N-butyl-N-acetyl]-aminopropionic acid)or oil of lemon eucalyptus [p-menthane 3, 8-diol (PMD)], use 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 concentration 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 the skin.
• More information on choosing and using repellents safely is included in the MDPH Mosquito Repellents fact sheet which can be viewed online at www.mass.gov/dph/wnv, and also the CDC http://www.cdc.gov/ncidod/dvbid/westnile/RepellentUpdates.htm, or National Pesticide Information Center (NPIC) toll free at 1-800-858-7378 or online at http://npic.orst.edu/index.html. If you can’t go online contact MDPH at (617)983-6800 for a hard copy of the fact sheet.
• Cover up the arms and legs of children playing outdoors. Baby carriages and playpens should be covered with mosquito netting.

There are certain actions that residents should take related to West Nile Virus (WNV).
Mosquito proof your home and drain standing water
• To prevent a yard from becoming a source for Culex mosquitoes, homeowners should make a thorough inspection of their property and remove, empty, cover or treat any water-holding containers. During the summer, mosquito larvae can complete their development in water within a week.
• Containers where mosquitoes commonly lay eggs include neglected swimming pools, water in loose fitting pool covers or tarps, unscreened rain barrels, rimless tires, and plastic toys. Check rain gutters and drains.
• Tires should be disposed of properly or stored inside.
• Rubbish barrels, wheelbarrows and small boats should be covered or stored upside down.
• The water in wading pools and birdbaths should be changed weekly.
• Infrequently used pools should be covered or properly maintained.
• Rainwater collection barrels should be screened, emptied once a week or treated with products containing Bti.
• Some mosquitoes like to come indoors. Keep them outside by having tightly-fitting screens on all of your windows and doors. Fix any holes in screens and screen doors and replace worn weather stripping.

For further information on WNV or EEE, log unto the Massachusetts Department of Public Health web site at www.mass.gov/dph/wnv or the US Centers for Disease Control and Prevention at http://www.cdc.gov/niosh/topics/westnile/. If residents have any questions about mosquitoes or how to control them, contact the East Middlesex Mosquito Control Project at 781-899-5730 or visit http://sudbury.ma.us/services/health/emmcp/.