An elderly Massachusetts man has died from a rare mosquito-borne illness he may have contracted recently while vacationing near Sebago Lake. While the deadly viral disease, Eastern Equine Encephalitis, has never been found in humans in Maine, public health officials warn it may become more common as temperatures rise in response to global climate change.
For people who live or vacation in Maine, said State Epidemiologist Dr. Kathleen Gensheimer, “The mosquito is like the state bird, just part of our everyday existence.” But with the emergence of serious diseases such as EEE and West Nile virus, she said Thursday, Mainers should get serious about avoiding contact with the ubiquitous insects.
The victim, a 73-year-old Essex County resident whose name has not been released, died Sunday at a Massachusetts hospital. His was the first Massachusetts death from EEE since 2005, when four cases were reported, including two fatalities. Nationwide, about one third of the people who contract EEE die from the brain inflammation, fever and other symptoms it causes.
The man’s illness was first reported Oct. 22, several weeks after he first developed symptoms while vacationing in the town of Naples near Sebago Lake. The victim had spent the previous two weeks in the Naples area and in Coos County in northern New Hampshire. Due to the incubation period of the illness, health officials believe he was exposed during that two-week window.
According to a public health advisory issued by the Maine Center for Disease Control and Prevention, EEE was determined to have caused the death in mid-September of a horse in Lebanon, a small York County town on the New Hampshire border. An emu also had tested positive for the virus in nearby Barnstead, N.H., at the time. The southwestern corner of Maine was thought to be a developing hot spot for the several mosquito species that are capable of transmitting the virus between horses, birds and humans, according to Gensheimer.
Then in early October, the Maine CDC reported that a mosquito pool in the York County town of Arundel had been found to contain the EEE virus. Testing in previous years in the coastal area had turned up no trace of the virus.
Gensheimer said Thursday that the testing in Arundel was performed somewhat randomly because a private company specializing in such environmental testing is located in the area. There’s no reason to think, she said, that EEE virus won’t be found in other areas — including around Sebago Lake — if they are tested when warmer weather returns.
“It’s an old axiom in public health,” she said. “If you don’t look for it, you won’t find it.” But the ability to look for EEE or other mosquito-borne viruses such as West Nile virus is limited by cost, Gensheimer said, and testing mosquito pools around the state is unlikely to be a priority for state or municipal officials during these cash-strapped times.
Until EEE virus crops up in more Maine communities — in mosquito pools, horses, birds or humans — towns will probably choose to spend their money on more pressing concerns, Gensheimer said. “They’ll hedge their bets until they have more cases. We’re a very crisis-driven society,” she said.
For those communities that do determine the presence of EEE or the particular mosquito species that transmit it, she said, the response should include the early-spring application of pesticides that kill mosquito larvae. Other pest management measures include improving natural drainage and eliminating pools of stagnant water in old tires and other locations.
On a personal level, Gensheimer said, Mainers must be conscientious about avoiding contact with mosquitoes by using DEET-containing repellent, wearing protective clothing and avoiding outdoor activity when mosquitoes are most active.
• There were approximately 220 confirmed cases of human EEE in the United States from 1964 to 2004.
• States with the largest number of cases are Florida, Georgia, Massachusetts and New Jersey.
• EEE virus transmission is most common around freshwater hardwood swamps in the Atlantic and Gulf Coast states and the Great Lakes region.
• Risk of exposure to infected mosquitoes may increase as the human population expands into natural areas where the virus circulates.
• EEE virus is transmitted to humans through the bite of an infected mosquito. It generally takes three to 10 days to develop symptoms of EEE after being bitten by an infected mosquito.
• Many infected individuals have no apparent illness. In those persons who do develop illness, symptoms range from mild flulike illness to inflammation of the brain and coma. In severe cases, death may result.
• The mortality rate from EEE is approximately one-third, making it one of the most deadly mosquito-borne diseases in the United States.
• There is no vaccine against EEE and no specific drug treatment to cure it.
• Approximately half of individuals who survive EEE will have mild to severe permanent neurological damage.
• Persons over age 50 and younger than age 15 seem to be at greatest risk for developing severe illness.
Source: U.S. Centers for Disease Control and Prevention