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Warren, Markey call on CDC to address potential EEE outbreak

An entomologist identified mosquito species at Dragon Mosquito Control in New Hampshire in 2005.
An entomologist identified mosquito species at Dragon Mosquito Control in New Hampshire in 2005.Darren McCollester/Getty Images

US senators from Massachusetts are asking for support from federal public health officials as the state braces for more cases of eastern equine encephalitis, a rare mosquito-borne illness that killed six residents in an outbreak last year and has infected one Plymouth County boy this summer.

Last year’s EEE outbreak was the state’s worst in more than 50 years, and already this year is looking like it could set new records, Senators Elizabeth Warren and Edward J. Markey said in a letter to Dr. Robert Redfield, the director of the US Centers for Disease Control and Prevention.

“Last summer, EEE surged across the United States, with 38 cases nationwide — up from the usual half a dozen cases,” Warren and Markey said. “Massachusetts was one of the states hit hardest, with 12 cases and 6 fatalities. Because typical EEE outbreaks last for two to three years, high case counts are likely to continue.”

EEE causes swelling in the brain and kills about 30 percent of those who contract the virus, according to the CDC. Those who survive are often left with neurological complications. There is no vaccine for humans and no preventative drug or treatment, though EEE vaccines are available for horses.


This year, the senators said, EEE has been found in Massachusetts mosquitoes earlier than in any of the previous 20 years and in at least two locations outside “the virus’ usual hotspots, suggesting the disease may have spread farther than originally anticipated.”

The COVID-19 pandemic has been a heavy burden for public health officials that has complicated efforts to address other issues, and “decades of chronic underfunding” have forced many public health departments to shift resources from EEE monitoring and mosquito control to the pandemic response, the senators said.

“Already, some staffers who typically set mosquito traps have been redeployed to COVID-19 call centers,” they said. “Elsewhere, state labs are too overwhelmed with COVID-19 tests to test mosquito samples for deadly illnesses.”


The senators asked the CDC to “continue to find every opportunity to support state and local governments and other agencies to address the threat of EEE and other vector-borne viruses,” and listed 10 questions about this year’s EEE outbreaks and the CDC’s response to the virus.

The agency did not respond Monday evening to an inquiry from the Globe.

In a March letter to Warren and Markey that was obtained by the Globe, Redfield acknowledged the spike in EEE infections in 2019 and said that last year the CDC provided $551,000 to Massachusetts to help address illnesses spread by insects and another $235,000 in supplemental funding to combat the state’s EEE outbreak.

Redfield said he shared the senators’ concerns for this year and pledged that the CDC would support efforts to address the illness.

“Supporting state and local vector-borne disease prevention and control programs is a priority for CDC, since disease cases from mosquitoes, ticks, and fleas in the United States tripled from 2004 [to] 2016, and state and local health departments and vector control organizations are the nation’s main defense against this increasing threat,” Redfield’s letter said.

Jeremy C. Fox can be reached at jeremy.fox@globe.com. Follow him on Twitter @jeremycfox.