The Massachusetts Department of Public Health has advised the Board of Health that a mosquito pool located in South Wayland tested positive for West Nile Virus (WNV) on 8/30/11. The mosquitoes identified are of the Culex species which are also known as “bridge” vectors that will feed on birds and people. West Nile Virus can be spread to humans from a mosquito bite.
We have been in contact with Dave Henley of Eastern Middlesex Mosquito Control Project to discuss his recommendations. He said there are almost 200 mosquito pools in the state that have tested positive for WNV so far, but there are no human cases yet. He is not recommending spraying in Wayland at this time but he is willing to attend our next Board of Health meeting to discuss spraying or alternatives. Wayland does not spray adult mosquitoes, we do larviciding in early spring and then we also treat the catch basins with ALTOSID XR briquettes that last 90 days. Spraying does not work well with Culex mosquitoes which carry WNV because these mosquitoes spend the night high up in trees and are hard to reach (they are where the birds are), spraying would kill other species of mosquitoes. If we had a mosquito pool with EEE then he would recommend spraying. There are a lot of new mosquitoes hatching out in general right now (not Culex species) and people will be noticing a lot of mosquitoes, however these mosquitoes would not necessarily be carrying the WNV at this time. Mr. Henley recommends that we should advise people to avoid getting mosquito bites. Wayland is still at this time considered a low risk area for mosquito born illness.
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.
Now that we have been notified of the presence of a mosquito pool in Wayland that tested positive for West Nile Virus (WNV), residents are urged to take preventative actions to avoid mosquito bites.
What you should do to avoid mosquito bites.
- Schedule outdoor events to avoid the hours between dusk and dawn, when mosquitoes are most active.
- When you are outdoors, wear long pants, a long-sleeved shirt and socks. Although uncomfortable during hot days, long-sleeve shirts and long pants can provide a layer of protection.
- 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)]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. If you can’t go online contact MDPH at (617)983-6800 for a hard copy.
- Be aware that mosquitoes are active in damp shady areas, during cloudy humid days, at dusk, dawn and during the night.
- Cover up the arms and legs of children playing outdoors. Baby carriages and playpens should be covered with mosquito netting.
- Fix any holes in screens and screen doors and replace worn weather stripping.
- There are certain actions that residents should take related to West Nile Virus (WNV).
- 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.
- 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.
For further information on WNV or EEE, please see the following resources:
- The Massachusetts Department of Public Health.
- The Public Health Fact Sheet, which includes ways in which to protect yourself from WNV
- The US Center for Disease Control and Prevention
- The East Middlesex Mosquito Control Project, or call them at 781-899-5730
- The Use and Effectiveness of Insect Repellants
- CDC Updated Information on Insect Repellants