Physician: Prevention Is Best Way to Combat Mosquito-borne Illness

WARE — The Mass. Department of Public Health (DPH) recently announced that 36 additional communities are now at moderate risk for West Nile virus (WNV), bringing the total number of communities at moderate risk to 59 spread across eight counties. “Moderate risk means mosquito activity is substantial enough that people should use personal protection to avoid being bitten by a mosquito,” said Dr. Richard Gerstein, Emergency Department Physician and site coordinator at Baystate Mary Lane in Ware.

“It doesn’t take much for mosquitos to breed,” said Gerstein. “The main rule when it comes to breeding grounds for mosquitoes is that they need stagnant water in order to lay their eggs. What most people don’t realize is the surprising number of areas around their own house where mosquitoes can find the stagnant water they need. Any temporary body of water that is present for more than a week can be a mosquito-breeding habitat. Even flooded tire tracks and footprints in a muddy field have been known to produce dozens of mosquitoes each.”

According to the DPH Deputy State Epidemiologist, Dr. Catherine Brown, the eight counties facing moderate risk are Hampden, Hampshire, Franklin, Essex, Middlesex, Norfolk, Suffolk, and Worcester counties. There have been no human cases of WNV this year. WNV is usually transmitted to humans through the bite of an infected mosquito. In 2016, there were 16 human cases of WNV infection acquired in Massachusetts. While WNV can infect people of all ages, people over the age of 50 are at higher risk for severe disease.

“It’s possible that some people who become infected with mosquito-borne viruses may not develop any symptoms or, in some cases, only flu-like symptoms,” said Gerstein. “The incubation period for the virus from the time of an infected mosquito bite to onset of illness ranges from four to 10 days, and the illness can last one to two weeks. Those infected usually develop lifelong immunity.

“The majority of people who are infected with WNV, approximately 80{06cf2b9696b159f874511d23dbc893eb1ac83014175ed30550cfff22781411e5}, will have no symptoms,” he went on. “A smaller number of people who become infected, less than 20{06cf2b9696b159f874511d23dbc893eb1ac83014175ed30550cfff22781411e5}, will have symptoms such as fever, headache, body aches, nausea, vomiting, and sometimes swollen lymph glands.  In less than 1 percent of infected people, the virus causes a serious neurological infection, including inflammation of the brain (encephalitis) and of the membranes surrounding the brain and spinal cord (meningitis).

Gerstein encourages community members to follow Department of Public Health tips to protect themselves and their loved ones from illnesses caused by mosquitoes:

• 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;
• Apply insect repellent when outdoors. Use a repellent with DEET, oil of lemon eucalyptus, or IR3535 according to the instructions on the product label. DEET products should not be used on infants under 2 months of age and should be used in concentrations of 30{06cf2b9696b159f874511d23dbc893eb1ac83014175ed30550cfff22781411e5} or less on older children. Oil of lemon eucalyptus should not be used on children under 3;
• Clothing can help reduce mosquito bites. Wearing long sleeves, long pants, and socks when outdoors will help keep mosquitoes away from your skin;
• Mosquito-proof your home. Limit the number of places around your home for mosquitoes to breed by either draining or discarding items that hold water. Remove containers that may hold water in places that are hard to see, such as under bushes, porches, decks, or stairs and eliminate standing water that collects on your property;
• Change the water in birdbaths every few days; aerate ornamental ponds or stock them with fish; and
• Install or repair screens. Keep mosquitoes outside by having tightly fitting screens on all of your windows and doors.

More information can be found on the Arbovirus Surveillance Information web page at www.mass.gov/dph/mosquito.