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Prevention is best way to combat mosquito-borne illness

September 07, 2012

Dr. Richard Gerstein, Chair of Emergency Medicine at Baystate Mary Lane Hospital alerts community members to the continued risk of mosquito-borne (arboviral) illnesses, such as those caused by West Nile virus (WNV) and Eastern equine encephalitis (EEE) virus. 

Although Labor Day is often considered the unofficial end of summer, infected mosquitoes persist and precautions should still be taken to avoid West Nile Virus (WNV) and Eastern Equine Encephalitis (EEE) which can be caused by an infected mosquito bite.  


The virus that causes EEE is a mosquito borne viral disease which can be spread when a mosquito bites an infected bird and then bites a human.  In Massachusetts, the virus is most often identified in mosquitoes found in and around freshwater and hardwood swamps.  Although humans and several other types of mammals, particularly horses and llamas, can become infected, they do not spread the disease.


EEE is relatively rare in humans, although there are occasional outbreaks in certain regions of the country. Fewer than 100 people have died from EEE in Massachusetts in the past 75 years, according to the Department of Public Health. In the United States, approximately 5-10 EEE cases are reported annually. The risk of getting EEE is highest from late July through September when more mosquitoes are present and active.


It is possible that some people who become infected with mosquito borne viruses may not develop any symptoms or in some cases only flu-like symptoms.  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.


Symptoms may include chills, fever, headache, vomiting, malaise, muscle aches and joint aches.  Inflammation and swelling of the brain, called encephalitis, is the most dangerous and serious complication. The disease gets worse quickly and causes serious neurological damage in infected people and can be fatal.  There is no specific treatment for EEE. Antibiotics are not effective against viruses, and no effective anti-viral drugs have been discovered for the treatment of EEE. Severe illnesses are treated by supportive therapy, which may include hospitalization, respiratory support, IV fluids and prevention of other infections.


Dr. Gerstein encourages community members to follow The Department of Public Health tips that will help people 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 (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.


         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.  Drain Standing Water, mosquitoes lay their eggs in standing water.  Mosquitoes can begin to multiply in any puddle or standing water that lasts for more than four days, and Mosquito breeding sites can be anywhere.  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.


         Install or Repair Screens. Keep mosquitoes outside by having tightly-fitting screens on all of your windows and doors.


More information about different types of mosquitoes that can spread the virus can be found on the MDPH website at


Dr. Richard Gerstein, Chair of Emergency Medicine at Baystate Mary Lane Hospital, joins his team of board certified Emergency Medicine Physicians who proudly provides expert care in the Baystate Mary Lane Hospital Emergency Department.  The Emergency Department is open 24 hours per day 7 days a week, providing urgent and emergent care for all medical, surgical and pediatric problems.  For more information about Baystate Mary Lane Hospital visit or friend us on Facebook.