The Massachusetts Department of Public Health (DPH) announced that a second human case of West Nile virus (WNV) has been confirmed in Middlesex County. The patient, a Cambridge man in his 70s, is currently hospitalized. The first human case of WNV this year was confirmed in another Middlesex County resident on August 15. In addition to the elevated threat level in Cambridge, the nearby communities of Arlington, Belmont, Boston, Brookline, Somerville and Watertown have been raised to a “High” WNV threat level.
“The announcement is a compelling indicator that the threat of mosquito-borne illness is widespread, and people should continue taking simple, common-sense steps to protect themselves and their families against mosquito bites,” said DPH Commissioner John Auerbach. “Use insect repellant, cover exposed skin, and avoid outdoor activities at dusk and after nightfall when mosquitoes are their most active.”
“Both Middlesex County cases have been identified as Cambridge residents,” said Claude Jacob, the city’s Chief Public Health Officer and director of the Cambridge Public Health Department. “Our department has been working with city and community partners to inform residents about the increased risk of West Nile virus this summer. We’re also working with the East Middlesex Mosquito Control Project and city departments to reduce mosquito breeding grounds.”
Health officials also announced that a diagnosis of Eastern Equine Encephalitis (EEE) has been confirmed in a horse stabled in Georgetown and in an alpaca stabled in Halifax. As a result, the EEE threat level has been raised to “Critical” in Georgetown, and to “High” in the nearby communities of Boxford, Groveland, Newbury, Rowley, and West Newbury. The EEE threat level has been raised to “Critical” in Halifax and to “High” in neighboring East Bridgewater, Hanson, Pembroke, and Plympton. Consistent with EEE threat level guidelines, DPH strongly recommends that evening outdoor events are curtailed in all these communities for the remainder of the mosquito season.
WNV infected mosquitoes have been found in 67 communities from nine counties so far during 2012. There were six cases of WNV in Massachusetts residents and one in a horse last year. While WNV can infect people of all ages, people over the age of 50 are at higher risk for severe disease. WNV is usually transmitted to humans through the bite of an infected mosquito. Most people infected with WNV will have no symptoms. When present, WNV symptoms tend to include fever and flu-like illness. In rare cases, more severe illness can occur.
There were two cases of EEE in August of last year acquired in Massachusetts, including a fatal case in a Bristol County man. EEE activity in both 2010 and 2011 raised public concern and prompted DPH to work with a panel of experts to evaluate and enhance the state’s surveillance and response program. EEE is spread to humans through the bite of an infected mosquito. EEE is a serious disease in all ages and can even cause death.
The following information is courtesy of The Cambridge Health Department
What is West Nile Virus?
West Nile virus (WNV) is a potentially serious illness spread by infected mosquitoes. The virus can cause illness ranging from a mild fever to more serious disease like encephalitis or meningitis. WNV is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall. This fact sheet contains important information that can help you recognize and prevent West Nile virus.
What are the symptoms of West Nile virus?
No Symptoms in Most People. Approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.
Milder Symptoms in Some People. Up to 20 percent of the people who become infected have symptoms such as fever, headache, body aches, nausea, vomiting, swollen lymph glands, or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.
Serious Symptoms in a Few People. About one in 150 people infected with WNV develop severe illness, including encephalitis or meningitis. The severe symptoms can include high fever, headache, stiff neck, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent. People older than 50 years of age have a higher risk of developing severe illness.
How common is West Nile virus in Massachusetts?
Because most people who are exposed to WNV have no symptoms, it is difficult to know exactly how many people have been infected. People who develop severe illness with WNV are most often reported. Between 2000 and 2010, 67 people were reported with WNV infection in Massachusetts. Six of these people died.
Is there any treatment?
There is no specific treatment for WNV infections. People with mild WNV infections usually recover on their own. In more severe cases, people usually need to go to the hospital where they can receive supportive treatment including intravenous fluids, help with breathing and nursing care.
How can people protect themselves from West Nile virus?
The easiest and best way to avoid WNV is to prevent mosquito bites.
- When you are outdoors, use insect repellent containing DEET, Picaridin, Oil of Lemon Eucalyptus, or IR3535.Follow the directions on the package.
- The mosquitoes that spread WNV are most active in the evening and at night. Be sure to use insect repellent andwear long sleeves and pants at these times or consider staying indoors during these hours.
- Make sure you have good screens on your windows and doors to keep mosquitoes out.
- Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets and barrels. Change thewater in pet dishes and replace the water in bird baths weekly. Drill holes in tire swings so water drains out.Keep children’s wading pools empty and on their sides when they aren’t being used.
More information on West Nile virus and other diseases spread by mosquitoes can be found at www.cdc.gov/westnile.
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.