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Cases of babesiosis, a deadly tickborne disease, are on the rise in New England

A sign near the entrance of Santuit Pond warns of potential ticks in the area on Saturday, July 22, 2023, in Mashpee, Mass.
Raquel C. Zaldívar
New England News Collaborative
A sign near the entrance of Santuit Pond warns of potential ticks in the area on Saturday, July 22, 2023, in Mashpee, Mass.

Last August, Kristen Smith spent weeks seeking multiple doctors to determine the culprit behind her throbbing headache, high-grade fever and shortness of breath.

Smith, 55, of Portland, Maine was initially diagnosed with strep throat at an urgent care clinic, she said. But after a few days of taking antibiotics, Smith felt worse.

Her second diagnosis, this time West Nile Virus, was delivered by her primary care doctor, she said. She was told with rest, she’d feel better in a few days.

She didn’t.

“My breathing started to become very labored. And I had literally no energy,” said Smith. “It was almost impossible to get from my bed to the bathroom, which was like ten feet away.”

She never expected a diagnosis of babesiosis, a dangerous and potentially deadly disease transmitted by the bite of the Blacklegged tick infected with the Babesia microti parasite. That diagnosis is on the rise in New England, due to climate change and more human interactions with ticks.

Smith told GBH News she went to the emergency room at Maine Medical Center, where doctors ordered a tick panel. While they awaited its results, she said, they treated her for anaplasmosis, a bacterial infection transmitted by ticks.

Her condition rapidly deteriorating, Smith said her doctor recommended she purchase a shower chair since she could no longer muster the strength to stand.

“That’s when I really started to realize that there was something terribly wrong,” said Smith. “And that nobody knew what it was and that I had not been properly diagnosed yet.”

Kristen Smith, of Portland, Maine says a diagnosis of Babesiosis has changed the way she approaches her time in the outdoors.
Kristen Smith
Kristen Smith, of Portland, Maine says a diagnosis of Babesiosis has changed the way she approaches her time in the outdoors.

After two weeks without a proper diagnosis, Smith returned to the emergency department. When doctors noticed her eyes and skin were jaundiced, they admitted her. With her tick panel results back, Smith finally received her correct diagnosis: babesiosis.

Babesiosis on the rise

Although Lyme disease is the most common tickborne illness in the U.S., cases of babesiosis caused by Babesia microti are increasing across New England. The first documented human case of babesiosis caused by Babesia microti in the U.S. was reported on Nantucket in 1969. Since then, babesiosis has spread into the Northeast and upper Midwest regions of the country.

According to the CDC, babesiosis cases more than doubled from 2011 to 2019, with Maine, Vermont and New Hampshire reaching endemic levels for the first time. The disease is now found in all seven New England states.

The majority of patients diagnosed with babesiosis are over the age of 50.

Dr. Edouard Vannier, an infectious disease researcher at Tufts Medical Center in Boston, said as the population ages, doctors should expect to see more patients infected with babesiosis.

“What people are not aware of is that you actually can die from babesiosis, but that you will rarely die from Lyme disease,” said Vannier.

Most people infected with babesiosis are asymptomatic or experience mild symptoms including fatigue, fever, headache and muscle aches, according to the Centers for Disease Control and Prevention, or CDC. But in severe cases, babesiosis can result in kidney failure and even death. Older adults, immunocompromised people and those without a spleen, like Smith, face a higher risk of developing a life-threatening condition.

A parasitic infection

Like malaria, the Babesia microti parasite destroys red blood cells. Because Smith doesn’t have a spleen, it caused the disease to progress more quickly than usual.

And with every misdiagnosis — of strep throat, West Nile Virus and anaplasmosis — her lifesaving treatment was delayed.

In the hospital, medical residents crowded into her room to hear about her case. A representative from the CDC arrived to tell Smith the agency would be monitoring her progress.

“I have not walked in the woods or in the grass with shorts on since this happened, and I don't think I ever will again." Kristen Smith

Smith received seven blood transfusions to increase her red blood count and was prescribed antibiotic and antiparasitic medication. After a week-long hospitalization, Smith went home to recover.

“The doctor told me that I easily could have died if I hadn’t come to the hospital when I did,” said Smith.

Prevention and treatment

Current preventative measures are limited. They include avoiding areas with ticks, wearing appropriate clothing, using insect repellents and performing tick checks.

But as the climate warms, tick season is extending and expanding, pushing the arachnids north into new territory.

“We have an increased number of cases of babesiosis here and increased geographic spread, partly due to climate and partly due to the fact that we have encroached into areas that were previously wooded,” said Dr. Cassandra Pierre, an epidemiologist at Boston Medical Center.

For people who contract babesiosis, the standard treatment is to take a combination of antiparasitic and antibiotic medications for seven to 10 days.

In rare cases, babesiosis can be transmitted from person to person through a blood transfusion. In 2019, the FDA recommended that areas with a high prevalence of the disease screen the blood supply for the Babesia microti parasite. But as the disease spreads and people travel, Pierre said it could become a future concern for the blood supply throughout the country.

Babesiosis symptoms mimic the flu

Former GBH employee Don Goonan, who is 69, remembers feeling chilled and dizzy at work one day in December 2019.

“I had my winter coat on and I remember sort of being distracted while I was working,” said Goonan. “The next thing I know my supervisor was shaking my shoulder and saying, ‘Don’t get mad, but I called an ambulance.’”

At a nearby hospital, Goonan was diagnosed with syncope, or a common fainting spell, he said.

Days later, Goonan felt worse and visited an urgent care center in Norwell, Massachusetts. A doctor ordered a blood smear and diagnosed Goonan with babesiosis.

“You could have blown me over with a feather,” said Goonan. “I wasn’t prepared for that kind of diagnosis.”

Neither Smith nor Goonan actually ever saw a tick. But doctors say that’s not unusual.

“The ticks are so small they can have a blood meal and detach without you seeing them.” Dr. Cassandra Pierre, BMC epidemiologist

Vannier said about half of the people diagnosed with babesiosis do not recall being bitten by a tick. Most people become infected after being bitten by a juvenile tick, or a nymph — about the size of a poppy seed — which can feed without being noticed. A tick must be attached for at least 24 hours to transmit the parasite.

“The ticks are so small they can have a blood meal and detach without you seeing them,” said Pierre. “And it can be a matter of one to two to three to four weeks before you actually develop symptoms after the tick has already bitten you.”

Patients should advocate for themselves if they suspect a tick illness, Pierre said.

“If you have a fever, malaise, fatigue for a few days, you’ve been to primary care, you’ve been to the E.D. [emergency department] and the symptoms aren’t getting better, especially if you’re one of those who belong to the group of people who could be at higher risk for severe disease, ask for a tick panel,” said Pierre.

Tick testing in Massachusetts

Instead of waiting for symptoms to appear, some people have turned to independent labs like the TickReport Testing Lab in Amherst, Massachusetts. The facility claims to have tested more than 100,000 ticks since opening in 2006. Education Director Paul Killinger said most ticks are sent in from individuals who find a tick on themselves or their pet and want to know their risk of exposure to a tickborne illness before developing symptoms.

“Usually within about a day of receiving it, we’ll have tested it for up to 25 pathogens. But most of what we find is about eight main pathogens,” Killinger said.

Killinger said testing is not a substitute for a medical diagnosis, but results can help inform doctors about treatment options. Test results are entered into a database so people are able to size up their risk by state or zip code.

“Some doctors are a little bit skeptical, but I think for a lot of individuals it offers a lot of information rather than just sort of waiting,” said Killinger.

The CDCdiscourages using tick testing labs for diagnosis, saying results can be unreliable.

Kristen Smith, now fully recovered, is taking steps to ensure she never winds up hosting a tick again.

“I have not walked in the woods or in the grass with shorts on since this happened, and I don’t think I ever will again,” Smith said. “Just realizing what a single tick bite can do to you makes me realize that I have to take full precautions at all times.”

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Dominique Farrell