Babesia is a malaria-like parasite carried by the same tick that carries Lyme. Because it is a parasite and not a bacterium, the antibiotics typically used for Lyme have no effect on it. It is seldom tested for, so people can finish Lyme treatment, still feel sick, and not understand why.

Key Takeaways

• Babesia is a parasite, a close cousin of malaria, that infects and destroys red blood cells, and the antibiotics used for Lyme have no effect on it.
• Its symptoms include fever, chills, drenching night sweats, deep fatigue, and shortness of breath that is easy to mistake for anxiety.
• You can catch it without a tick bite, because it is one of the most common parasites passed through blood transfusions in the United States.
• It is established in the DMV. Half of the local ticks carrying Babesia also carried Lyme, and the researchers tracking it call the known cases the tip of the iceberg.
• It is seldom tested for. Across seven large US labs, only about one Babesia test was ordered for every twenty-five Lyme tests.

What is Babesia, and why don't Lyme antibiotics work on it?

Because Babesia is a parasite and not a bacterium, the antibiotics typically used for Lyme have no effect on it. It is a close cousin of the parasite that causes malaria. It moves into your red blood cells and bursts them from the inside. Lyme is bacterial. Babesia is not. The two need different treatment.

Someone carrying both infections can take every Lyme pill as prescribed and still feel sick, because one of the infections was never treated. In tick-borne medicine, that gap is a common reason a case gets written off as treatment failure. The real problem is a second infection no one looked for.

‍

‍

Lyme is a bacterium treated with antibiotics and tested routinely. Babesia is a parasite treated with atovaquone plus azithromycin, not cleared by the doxycycline used for Lyme, and rarely tested at about one Babesia test for every twenty-five Lyme tests. Treat the Lyme alone and the Babesia can go untreated.

What does Babesia feel like?

Babesia can cause shortness of breath that is easy to mistake for anxiety, which is one reason it gets missed. Some clinicians who treat tick-borne illness call it air hunger, the sense that you cannot get a full breath. It comes alongside the infection's more common signs. Those are waves of fever and chills, drenching night sweats that soak the sheets, and a fatigue deeper than ordinary tiredness. Shortness of breath has many causes, including anemia from the way Babesia destroys red blood cells. It deserves a real workup, not a quick label of stress.

What symptoms does Babesia cause that Lyme doesn't?

Because Babesia destroys red blood cells, it can turn urine tea-colored and tint the skin and the whites of the eyes yellow, signs that Lyme never causes. These are signs of hemolysis, the breakdown of red blood cells. When they appear, they point beyond Lyme, to something its antibiotics do not treat.

Two rarer signs matter because either can be the first thing anyone notices:

• After the Babesia itself is treated, the immune system can keep destroying the body's own red blood cells, even once the parasite is no longer detectable. This shows up most often in people without a spleen or with a weakened immune system.
• The spleen can rupture with no injury at all, sometimes in young, healthy people who carry only a trace of the parasite. Now and then, that rupture is the first sign of infection.

What else commonly gets diagnosed instead of Babesia?

In our practice we regularly see Babesia symptoms attributed to anxiety, panic attacks, or perimenopause before anyone looks for a parasite. The same symptoms map onto more familiar explanations:

• Shortness of breath gets read as a panic attack.
• Drenching night sweats get read as perimenopause or menopause.
• Deep fatigue gets read as stress or low mood.

Each label is reasonable on its own. None of them account for a tick-borne parasite, so the real cause sits untested while the labels pile up.

‍

‍

Can you get Babesia without a tick bite?

You can catch Babesia without a tick bite, because it is one of the most common parasites passed through blood transfusions in the United States. People can carry it with no symptoms and donate blood while infected. In a screening study across four high-risk states, about 0.38 percent of donations flagged positive on the first test, and fewer were confirmed on repeat testing. Some infected donors feel healthy and never know they carry it.

Ticks are still the main way people get Babesia, by a wide margin. Tick-borne cases run into the thousands each year, while only about 160 transfusion cases have been documented in roughly three decades of tracking.

Is donated blood screened for Babesia?

Screening for Babesia in donated blood is regional, not nationwide, and the DMV is inside the screening zone. In 2019 the FDA recommended year-round testing in the higher-risk states, and Maryland, Virginia, and Washington DC are on that list. Elsewhere, donors are only asked whether they have ever tested positive. For years this area was not covered, and the rules changed as the parasite took hold here.

Can you get Babesia and not know it for years?

People can carry Babesia for months, sometimes years, while feeling fine, which is why the timing of a test matters as much as the test itself. Infection often causes no symptoms at all, so it can enter the blood supply through donors who feel well. Some people feel fine for a long stretch and become ill later, when they may not even remember a tick bite.

Timing changes what a test can see. Early on, the body may not have made enough antibodies yet. An antibody test can then read negative while the infection is real. Later, the parasite can sit at levels too low for a standard blood smear to catch. A smear or DNA test, taken while symptoms are active, gives a clearer answer than antibodies alone.

Is Babesia in the DMV?

Babesia is established in the DMV, and half of the local ticks carrying it were also carrying Lyme. It took hold here later than most local doctors realize. The first local cases appeared in Maryland in 2009, Washington DC in 2013, and Virginia in 2016. The parasite now turns up in about 2.7 percent of local blacklegged ticks. The known human cases cluster around Baltimore, the Eastern Shore, and the DC suburbs of Loudoun and Fairfax. The team that mapped this calls the reported cases the tip of the iceberg, for a plain reason. Doctors in a newly affected area have not yet had cause to look. Unexplained night sweats, shortness of breath, or fatigue after Lyme treatment deserves a much closer look here than it did ten years ago. For the fuller regional picture, see our guide to Lyme disease in Northern Virginia, Maryland, and DC.

How often does Babesia get missed?

Across seven large US labs, only about one Babesia test was ordered for every twenty-five Lyme tests. That ratio comes from a 2016 analysis of commercial-lab ordering, so read it as direction, not a current number.

The reasons are structural:

• National guidelines tell doctors to test mainly when a patient is severely ill or fails to improve.
• A routine Lyme diagnosis does not trigger a Babesia test on its own.
• Appointments are short.
• The standard test can miss the parasite when levels are low.
• In about nine states, babesiosis is still not a reportable disease, so cases there never reach the national count.

Reported cases have climbed to a national high of about 3,586 in 2023, the most in the decade the CDC tracks. Even that number runs below the true count. Babesia is found only when someone thinks to look for it, and a routine Lyme workup rarely does.

Can Babesia be cured, or does it come back?

In most healthy people the infection clears with a specific drug combination, usually atovaquone plus azithromycin, though it can persist or relapse in people with weakened immune systems. That combination is different from the doxycycline used for Lyme, and a clear-cut case is treated with a short course of it. After treatment, the blood clears and most people recover.

Even after a clear-cut cure, low levels of the parasite can linger for a time after symptoms resolve. True relapse is documented mainly in people with weakened immune systems. Examples are those without a spleen or on treatment that suppresses immunity. The major medical societies agree on how to treat a clear-cut infection and differ on lingering illness. The IDSA reserves extended treatment mainly for the most immune-compromised patients. ILADS recognizes persistent infection more broadly and treats it longer. A Lyme-literate clinician can walk you through where your own case fits.

If you finished Lyme treatment and still feel sick

If you followed your Lyme treatment exactly and still feel unwell, the problem may be an infection that was never tested for. A short appointment and a single Lyme test cannot catch everything one tick can carry. Babesia is one of the infections most likely to slip through. At Indigo Integrative Health Clinic, we are trained to look for the co-infections a standard workup skips. Across the DMV they are common, easy to miss, and treated differently from Lyme. In our practice, we regularly see people who kept their symptoms long after Lyme treatment. A second infection was never on the list.

A complimentary 20-minute Discovery Call is where every Indigo patient starts. It is a short screening call to hear your history and help you figure out whether a closer look makes sense. Book a free Discovery Call.