West Nile Virus (WNV) in Somerville
Updates & Alerts
About Mosquito-Borne Illness
Updates & Alerts
One Case of West Nile Virus Confirmed in Somerville; City Now Considered ‘High Risk’
This week, the Massachusetts Department of Public Health (DPH) elevated Somerville and some surrounding communities to high risk for West Nile virus (WNV). One case of WNV has been confirmed in Somerville this year. Peak risk for WNV infection typically continues through September. Eastern Equine Encephalitis (EEE) cases have also been confirmed in Massachusetts this season, although the local risk for EEE remains low.
WNV and EEE are usually transmitted to humans through the bite of an infected mosquito. While WNV and EEE can infect people of all ages, people over the age of 50 are at higher risk for severe WNV, and people under the age of 15 are particularly vulnerable to EEE. WNV symptoms and EEE symptoms tend to include fever and flu-like illness.
Somerville residents are encouraged to continue to take precautions to protect themselves and their loved ones against mosquito bites and mosquito-borne illnesses. DPH recommends the following precautions:
Avoid Mosquito Bites
- Apply insect repellent when outdoors. Use a repellent with DEET (N, N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), oil of lemon eucalyptus [p-methane 3, 8-diol (PMD)], or IR3535 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.
- 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 the evening or early morning.
- Clothing can help reduce mosquito bites. Wear long-sleeves, long pants, and socks when outdoors to help keep mosquitoes away from your 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 discarding items that hold water. Check rain gutters and drains. Empty any unused flowerpots and wading pools, and change the water in birdbaths frequently.
- Install or repair screens. Keep mosquitoes outside by having tightly-fitting screens on all of your windows and doors.
Protect Your Animals
Animal owners should reduce potential mosquito breeding sites on their property by eliminating standing water from containers such as water bowls, buckets, tires, and wading pools – especially after heavy rains. Owners should also speak with their veterinarian about mosquito repellents approved for use in animals and vaccinations to prevent WNV and EEE. If an animal is diagnosed with WNV or EEE, owners are required to report to the Massachusetts Division of Animal Health by calling 617-626-1795 and to the Massachusetts Department of Public Health (DPH) by calling 617-983-6800.
More information, including all WNV and EEE positive results, can be found on the Arbovirus Surveillance Information web page at www.mass.gov/dph/mosquito or by calling the Massachusetts DPH Epidemiology Program at 617-983-6800.
About Mosquito-Borne Illness
What is Mosquito-borne illness?
Mosquito-borne illness is spread by the bite of an infected mosquito. In the Northeastern United States, it is usually caused by viruses such as West Nile Virus or Eastern Equine Encephalitis virus.
How common is mosquito-borne illness?
There is a low risk of infection following a mosquito bite. Most people bitten by infected mosquitoes experience no illness or only mild illness, but a small number of people can develop a more serious disease.
How is it spread?
Mosquito-borne illness is spread to people through the bite of an infected mosquito.
When is it spread?
The time of the year when mosquitoes are most active and most likely to carry disease is between late July and late September, but if the weather remains warm, the risk period can extend as late as November. The time of day when mosquitoes are most active is at night, dusk and dawn, but you can be bitten at any time.
Am I at risk?
People at higher risk for developing serious symptoms from WNV are those over age 50; however, Eastern Equine Encephalitis can cause serious illness in any age group.
What should I do if I get bitten by a mosquito?
Mosquito-borne illness is very rare in Somerville. So your risk following a mosquito bite is small. However, you should see your doctor immediately if you develop high fever, confusion, severe headache, stiff neck, or if your eyes become sensitive to light.