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If you have other questions or concerns, please call the Public Health Division, 508-862-4644.
Preventing West Nile Virus
The threat of West Nile virus exists whenever mosquitoes are active, typically at dawn and dusk. You should also be aware that mosquitoes are active at night and in damp, shady areas (such as forests) during daytime.
Protect Yourself
It is important for residents to remember that the risk of West Nile virus infection is present in places you may not expect, such as your porch or backyard. Barnstable residents can protect themselves from mosquito bites by taking some simple precautions.
- Repair any rips or tears in window screens or door screens that would allow mosquitoes to enter your home. Also, make sure your screens are tightly attached.
- People who spend time outdoors, especially in places attractive to mosquitoes, should consider wearing loose, long-sleeve shirts, loose pants, and socks.
- When outdoors, residents should also apply insect repellant that contains DEET to clothing and exposed skin. Don't apply repellent to skin that is under clothing. Heavy application is not necessary to achieve protection.
- Adults should use repellant with less than 30% DEET, while children should wear repellant that contains no more than 10% to 15% DEET. Repellent containing DEET should never be used on infants younger than 2 months of age.
- Whenever you use an insecticide or insect repellent, be sure to read and follow the manufacturer's directions for use of the product. For more information about repellents, see the CDC's fact sheet on insect repellent use and safety.
- When outdoors, cover your baby's stroller or playpen with netting.
Reduce Standing Water
Water that remains stagnant for seven days or longer can serve as a mosquito-breeding habitat. To prevent your yard from becoming a source of mosquitoes, you should carefully inspect your property and remove, empty, cover or treat any standing water. Common sources of standing water include old tires, clogged gutters, wheelbarrows, pots, wading pools, birdbaths, fish ponds, and discarded containers.
Here are some simple tips:
- To ensure that your property is not contributing to the mosquito population, walk around your property every 7 to 10 days and look for standing water.
- If you find standing water, make every effort to eliminate it. If you can’t get rid of the water, you should disturb the water every week to 10 days to ensure that no mosquito larvae can develop.
- Families should keep children's wading pools empty and on their sides when they aren't in use.
- Residents should replace water in birdbaths weekly.
Please remember that water in streets is not likely to harbor mosquito larvae unless it remains undisturbed for a week or more. (Cars driving through puddles make it very difficult for larvae to progress to adulthood!)
How Do People Get Infected with WNV?
West Nile virus is a parasite that lives in the blood of mosquitoes, animals, and humans. When viral levels reach a high enough concentration in a host's blood, feeding mosquitoes become infected and can transmit the virus back to animals and humans. While West Nile virus has many hosts, scientists consider the bird to be its principal reservoir.
In a very small number of cases, West Nile virus also has spread through blood transfusions, organ transplants, breastfeeding, and during pregnancy from mother to baby.
What Are Symptoms of WNV?
Most West Nile infections are so mild that the vast majority of people infected have no symptoms at all.
Another 20% of people who become infected will infected will develop West Nile fever. Symptoms include fever, headache, tiredness, nausea, vomiting, and sometimes swollen lymph glands or a skin rash. Symptoms can last for as short as a few days, though even healthy people have been sick for several weeks.
Less than 1% of the people bitten by a West Nile-infected mosquito will develop a life-threatening neurological illness. In these rare instances, the virus can wreak havoc on the brain, causing cerebral swelling (encephalitis) or inflammation of the membranes enveloping the brain and spinal cord (meningitis).
Severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.
If you think you have symptoms of West Nile virus, contact your health care provider.
People over the age of 50 who get infected with West Nile virus are more likely to develop serious symptoms, and should take special care to avoid mosquito bites.
Does Massachusetts have an effective mosquito surveillance and abatement program?
Active statewide surveillance of mosquitoes and passive surveillance (health department receives reports) of birds, horses, and humans for WNV infection is underway. When WNV is detected, active local surveillance (health department seeks reports) for birds, horses, and human cases may be implemented. When WNV is detected in a locality, the first level of response is to remind the public to eliminate mosquito breeding sites from their property and to avoid mosquito bites through adequate use of screens on doors and windows and proper use of repellents. Preemptive, intensified local mosquito control measures may be indicated as outlined in the Massachusetts Surveillance and Response Plan for Eastern Equine Encephalitis and West Nile Encephalitis. For a copy of this plan please visit the MDPH website at http://www.mass.gov/dph/wnv/wnv1.htm.
What about the dead bird in my yard (will it be tested)?
If you are aware of a bird(s) that recently died in your area, call MDPH’s Public Health Information Line at 866-MASS-WNV (866-627-7968). While most dead birds will not be collected and tested for WNV, keeping track of their locations plays an important role in directing further bird, mosquito and human surveillance activities. The information gathered from these surveillance activities may help to identify areas at increased risk for human WNV disease.
If MDPH informs you that the particular bird(s) should be tested, please call the Public Health Division Office (508) 910-1804 to have the bird collected for testing.
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