The Mosquito-Borne Disease ‘Triple E’ Is Spreading in the US as Temperatures Rise
This story originally appeared on Grist and is part of the Climate Desk collaboration.A 41-year-old man in New Hampshire died last week after contracting a rare mosquito-borne illness called eastern equine encephalitis virus, also known as EEE or “triple E.” It was New Hampshire’s first human case of the disease in a decade. Four other human EEE infections have been reported this year, in Wisconsin, New Jersey, Massachusetts, and Vermont.Though this outbreak is small, and triple E does not pose a risk to most people living in the United States, public health officials and researchers are concerned about the threat the deadly virus poses to the public, both this year and in future summers. There is no known cure for the disease, which can cause severe flu-like symptoms and seizures in humans four to 10 days after exposure and kills between 30 and 40 percent of the people it infects. Half of the people who survive a triple E infection are left with permanent neurological damage. Because of EEE’s high mortality rate, state officials have begun spraying insecticide in Massachusetts, where 10 communities have been designated “critical” or “high risk” for triple E. Towns in the state shuttered their parks from dusk to dawn and warned people to stay inside after 6 pm, when mosquitoes are most active.Like West Nile virus, another mosquito-borne illness that poses a risk to people in the US every summer, triple E is constrained by environmental factors that are changing rapidly as the planet warms. That’s because mosquitoes thrive in the hotter, wetter conditions that climate change is producing.“We have seen a resurgence of activity with eastern equine encephalitis virus over the course of the past 10 or so years,” said Theodore G. Andreadis, a researcher who studied mosquito-borne diseases at the Connecticut Agricultural Experiment Station, a state government research and public outreach outfit, for 35 years. “And we’ve seen an advancement into more northern regions where it had previously not been detected.” Researchers don’t know what causes the virus to surge and abate, but Andreadis said it’s clear that climate change is one of the factors spurring its spread, particularly into new regions.The first triple E outbreak on record occurred in Massachusetts in the 1830s in horses—the reason one of the three Es stands for “equine.” It wasn’t until a full century later, in 1934, that mosquitoes were incriminated as potential vectors for the disease. The first recorded human cases of the disease also occurred in Massachusetts four years later, in 1938. There were 38 human cases in the state that year; 25 of them were fatal. Since then, human cases have mostly been registered in Gulf Coast states and, increasingly, the Northeast. From 1964 to 2002, in the Northeast, there was less than one case of the disease per year. From 2003 to 2019, the average in the region increased to between four and five cases per year.
Eastern equine encephalitis, which has a high mortality rate, is becoming more common in North America as climate changes expands the habitats of insects.
This story originally appeared on Grist and is part of the Climate Desk collaboration.
A 41-year-old man in New Hampshire died last week after contracting a rare mosquito-borne illness called eastern equine encephalitis virus, also known as EEE or “triple E.” It was New Hampshire’s first human case of the disease in a decade. Four other human EEE infections have been reported this year, in Wisconsin, New Jersey, Massachusetts, and Vermont.
Though this outbreak is small, and triple E does not pose a risk to most people living in the United States, public health officials and researchers are concerned about the threat the deadly virus poses to the public, both this year and in future summers. There is no known cure for the disease, which can cause severe flu-like symptoms and seizures in humans four to 10 days after exposure and kills between 30 and 40 percent of the people it infects. Half of the people who survive a triple E infection are left with permanent neurological damage. Because of EEE’s high mortality rate, state officials have begun spraying insecticide in Massachusetts, where 10 communities have been designated “critical” or “high risk” for triple E. Towns in the state shuttered their parks from dusk to dawn and warned people to stay inside after 6 pm, when mosquitoes are most active.
Like West Nile virus, another mosquito-borne illness that poses a risk to people in the US every summer, triple E is constrained by environmental factors that are changing rapidly as the planet warms. That’s because mosquitoes thrive in the hotter, wetter conditions that climate change is producing.
“We have seen a resurgence of activity with eastern equine encephalitis virus over the course of the past 10 or so years,” said Theodore G. Andreadis, a researcher who studied mosquito-borne diseases at the Connecticut Agricultural Experiment Station, a state government research and public outreach outfit, for 35 years. “And we’ve seen an advancement into more northern regions where it had previously not been detected.” Researchers don’t know what causes the virus to surge and abate, but Andreadis said it’s clear that climate change is one of the factors spurring its spread, particularly into new regions.
The first triple E outbreak on record occurred in Massachusetts in the 1830s in horses—the reason one of the three Es stands for “equine.” It wasn’t until a full century later, in 1934, that mosquitoes were incriminated as potential vectors for the disease. The first recorded human cases of the disease also occurred in Massachusetts four years later, in 1938. There were 38 human cases in the state that year; 25 of them were fatal. Since then, human cases have mostly been registered in Gulf Coast states and, increasingly, the Northeast. From 1964 to 2002, in the Northeast, there was less than one case of the disease per year. From 2003 to 2019, the average in the region increased to between four and five cases per year.