Laurie Sylvia

Laurie Sylvia, 59, fell ill last Monday and by Saturday she had died of the Eastern Equine Encephalitis virus
A Massachusetts woman has died from the rare eastern equine encephalitis (EEE) virus, making her one of four in the state to have contracted the deadly mosquito-borne virus.

Laurie Sylvia, 59, began feeling sick last Monday and by Saturday the realtor and grandmother from Bristol County had passed away, her husband of 40 years, Robert Sylvia Jr, confirmed.

Earlier this month, a Massachusetts man over 60 years old fell into a coma after contracting the disease that either comes on like a sudden, intense cold, then disappears altogether, or comes on more slowly, but severely, causing diarrhea, vomiting, headache and loss of appetite.

Between 30 and 50 percent of people that contract the rare bug-borne disease don't survive it, putting Massachusetts on high alert as Sylvia is the first death reported in the state this year.

Sylvia's daughter, Jen Sylvia, took to Facebook to mourn her 'best friend'.

'She brought light and joy to everyone she came across,' Jen wrote Sunday. 'She was such a beautiful soul. I don't know where to go from here. I just don't understand how such a beautiful person could be taken from me so soon.'

Over the course of the last decade, there have been more cases of EEE in Florida than any other state.

But Massachusetts comes in a close second.

Between 2009 and 2018, Florida has seen 13 cases of EEE. Massachusetts has seen 10.

And only one state West of the Mississippi River - Montana - has had a single case of the virus in the same time period.

Massachusetts began spraying a pesticide on August 8, to try to kill off some of the disease-carrying bugs, the health department said.

Health department officials had not identified the man who fell into a coma aside from giving an approximate age and the fact that he lives in Plymouth county but Tess Hiller Hedblom, from Rochester, Massachusetts, posted to Facebook about her father's diagnosis.

'The news is both shocking and heartbreaking,' she wrote.

Tess said she and her family had no idea where or when her father was bitten and as of August 16, he remained in a coma.

There are only about six cases of the brain-swelling illness in the US a year on average - but as the planet warms, mosquito-borne diseases are a growing risk, especially on the East Coast, where mosquitoes that carry EEE live.

'Today's news is evidence of the significant risk from EEE and we are asking residents to take this risk very seriously,' said Massachusetts Public Health Commissioner Dr Monica Bharel, MD, at the time of Hedblom's father's diagnosis.

'We will continue to monitor this situation and the impacted communities.'

EEE makes its home base in Florida, where the climate and wetlands make a fertile breeding ground for mosquitoes that carry EEE. Though the virus is named for horses, the main carriers of EEE are bugs that feed almost exclusively on birds.

Bitten birds then migrate North with EEE as their passengers. Many spend their summers in Massachusetts's rural or once-rural areas.

There, the omnivores of the mosquito family bite the infected birds, get themselves infected too, and will go on to infect whatever their next prey is.

Most of the time they bite horses, chickens or other animals. On rare occasions though, they bite humans.

'We're a fatal endpoint - and vice versa,' Dr Thomas Unnasch, a University of South Florida professor of infectious diseases and expert on EEE, previously told DailyMail.com.

'There's no accidental pressure to adapt to us, so the virus less pathogenic....We just end up dead and so does the virus.'

Between 35 and 60 percent of people who get EEE die of the virus, which means that humans aren't a terribly advantageous target for the virus.

But humans are unintentionally offering themselves up to EEE-infected mosquitoes.

'In the upland swamp areas' - like parts of Massachusetts - there's more development in those areas, people are living closer to those wilder areas,' says Dr Unnasch.

'I'm a great example. Here in Florida, I live next to a nature conservancy. It's just beautiful. And it's a beautiful habitat for EEE - and I paid extra money to live next to that!'

Not only are humans moving in closer to EEE-infected mosquitoes' habitats, those habitats are getting more hospitable.

It used to be that, although birds carrying the virus migrate to the North, the winter would be harsh enough to kill off the mosquitoes and other animals that carry it.

'But there's been a lot of [virus] activity over the last three to five years, I think, because the winters are getting less cold and less severe, so the virus can over-winter year-to-year,' Dr Unnasch says.

And when it does strike a human, it can strike deep, infecting the brain stem.