A tick-borne parasite once mostly confined to parts of the Northeast and Midwest is no longer staying put. Babesiosis has now crept into Virginia, Maryland, West Virginia, and even Washington, D.C., according to a recent study. And experts are sounding the alarm before it gets worse.
The findings, published in the Journal of Medical Entomology, mark a significant geographic shift for a disease that was once considered relatively localized. Now, more than ever, public health officials are calling for increased awareness — before it spreads further.
A New Player in Tick Territory
The disease, caused by a microscopic parasite that infects red blood cells, spreads through bites from black-legged ticks — the same ones that transmit Lyme disease.
While some folks infected with babesiosis might not show a single symptom, others aren’t so lucky. Fever, chills, fatigue, and in more serious cases, hemolytic anemia — where red blood cells are destroyed faster than they can be made — can hit hard.
And for certain people, things can spiral fast.
One sentence to keep it real.
If you’re over 50, immunocompromised, have liver or kidney issues, or don’t have a spleen, babesiosis can turn deadly.
Why This Disease Has Experts So Worried
The Centers for Disease Control and Prevention (CDC) confirmed what many researchers suspected: babesiosis is no longer rare, and it’s climbing.
The numbers? Over 2,000 reported cases annually and growing. Ten states, including Connecticut and Minnesota, are now classified as endemic zones. And that list is expanding.
Here’s what has health professionals on edge:
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Coinfection with Lyme disease is more common than many realize, and those cases can be harder to diagnose and treat.
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The disease is sometimes passed through blood transfusions. This means the risk goes far beyond hiking trails or backyard gardens.
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Mortality rates? Around 2% of general cases, up to 10% in the immunocompromised, and a staggering 20% if spread through blood transfusion.
That’s not just concerning. That’s a ticking public health crisis.
Coinfections Are Making Things Messy
Richard Ostfeld, a senior scientist at the Cary Institute of Ecosystem Studies, pointed out that babesiosis is following Lyme disease’s footsteps — spreading in the same regions and transmitted by the same tick.
Nicole Baumgarth from Johns Hopkins warns of the diagnostic challenges.
Tick bite? Check.
Treated for Lyme? Check.
Still sick? That could be babesiosis hiding in plain sight.
Doctors may treat a patient for Lyme and call it a day — but if babesiosis is also there, and isn’t treated, symptoms can persist or worsen.
That misdiagnosis has a name: post-treatment Lyme disease syndrome. And in some cases, it’s just plain wrong.
How Babesiosis is Spreading and Where It’s Headed
Babesiosis has been a slow-burn problem for decades, but recent years have shown a worrying trend. Climate change, warmer winters, and expanding deer populations mean ticks are thriving — and they’re moving.
Here’s a snapshot of what we know:
| State/Region | Status | Notable Detail |
|---|---|---|
| Connecticut | Endemic | High case volume; one of first known hotspots |
| Virginia | Newly affected | Follows rise in Lyme reports |
| Washington, D.C. | Newly affected | Urban spread raising eyebrows |
| West Virginia | Newly affected | Tick populations increasing statewide |
| Minnesota/Wisconsin | Longstanding endemic | Still seeing high and growing numbers |
Jeffrey Wilson from the University of Virginia put it bluntly: “This isn’t a surprise, but it’s not something we can ignore anymore.”
Diagnosing Is Easy—If You Know What You’re Looking For
Baumgarth explains that babesiosis parasites live in the bloodstream — making them visible under a microscope, unlike Lyme disease bacteria.
That’s a small silver lining.
But the problem?
Doctors often aren’t trained to spot it, especially outside traditional hotspots.
And if someone donates blood while infected, it could pose a serious risk to recipients, especially those who are already sick.
Screening blood for Babesia is becoming more necessary — maybe even overdue.
Prevention is Still Our Best Bet
There’s no vaccine for babesiosis. That’s the bad news.
But there are plenty of things people can do to avoid ticks in the first place.
The CDC recommends simple but effective steps:
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Stick to the center of trails when walking outdoors.
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Avoid grassy, brushy, or wooded areas.
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Wear long sleeves, pants, and tuck in your clothes.
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Use 0.5% permethrin on clothing and gear — it keeps protecting after a few washes.
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Do tick checks. Every time.
Dr. Maria Diuk-Wasser from Columbia University mentioned something helpful: a free app called The Tick App. Snap a photo of a tick, upload it, and experts help ID it.
Small effort. Big peace of mind.
Research and Funding Falling Behind
Despite the growing concern, scientists are running out of money to study this. Ostfeld didn’t sugarcoat it — federal research funds are drying up.
And that’s not just bad news for babesiosis.
Ticks can transmit multiple diseases. Some we don’t even fully understand yet.
Durland Fish from Yale pointed out that while there are vaccines for Lyme in the pipeline, none will protect against babesiosis. And they won’t help with any of the other diseases that deer ticks carry either.
In short? We’re behind.
