Massachusetts mosquito-borne virus risk is ‘critical,’ health officials warn

Mosquito-borne virus kills one and sickens four in Massachusetts as health official warn people to apply DEET insect repellent as EEE threat grips the state

  • Eastern equine encephalitis is a rare mosquito-borne disease 
  • It causes life-threatening brain swelling 
  • US cases average 7 a year but Massachusetts has seen 4 already and one death 
  • State health officials warned that 4 more infected horses mean risks are ‘critical’ in 28 communities ahead of Labor Day weekend 

Massachusetts residents’ risks for a potentially deadly mosquito-borne virus are now ‘critical,’ state health officials announced ahead of Labor Day weekend in a Thursday statement.

So far, four cases of Eastern equine encephalitis (EEE) have been confirmed in humans in the state. One woman has died and three people have been sickened.

But officials’ latest warning comes after the department confirmed four additional cases in horses – for a total of seven this year – a bellwether that the disease could still actively spread. 

Officials are warning that the risk is now ‘critical’ in 28 Massachusetts communities, ‘high’ in 37 and moderate in 126 towns and cities, and advising citizens to avoid the outdoors at dawn and dusk and wear DEET insect repellent to minimize risks. 

The risk of transmission of Eastern equine encephalitis is critical in 28 Massachusetts communities (red) and high in 37 (orange) state officials warned ahead of Labor Day weekend

‘As we head into the Labor Day weekend and the month of September people should not forget to bring and use an EPA-approved mosquito repellent for any outdoor activities,’ said Public Health Commissioner Dr Monica Bharel.

So far, 366 mosquitoes tested in the state have been positive for EEE. 

The virus carried by the insects first triggers flu-like symptoms which can then progress to life-threatening brain swelling. 

Many patients descend into a coma. About a third die of the disease or its complications. 

On average, there are just seven cases of EEE in humans a year in the US – but numbers are rising as global warming drives temperatures up, scientists suspect. 

Already, Massachusetts alone is on track to surpass that total. 

New Jersey and Michigan have each confirmed one case. 

This week’s updated risk levels are updated largely because of the virus’s detection in additional horses in Massachusetts, rather than confirmed human cases, but health department officials urge people to take their warnings seriously. 

‘Horses and other mammals are an important part of mosquito-borne disease surveillance because they are exposed by the same kinds of mosquitoes that can expose people,’ said State Epidemiologist Dr Catherine Brown.

Residents of Fairhaven, Massachusetts, have reported finding dead birds that they’re concerned may carry the virus too.

Health officials in the town are unable to test the birds for EEE and are pleading with their citizens to stop bringing the deceased animals to their offices. 

In addition to wearing insect repellent, draining standing water can help reduce the risk of EEE transmission as stagnant water is fertile breeding ground for the bugs. 

Installing window screens can also help keep mosquitoes out and, if you must go outside, officials advise wearing long sleeves and pants.