Babesiosis is a tick-borne disease that is an emerging health concern in the United States. The U.S. Centers for Disease Control and Prevention (CDC) notes that infections are rising, particularly in the Northeast and Midwest. Nearly 3,600 cases were documented as of 2023, more than double the number of cases in 2014. While many people experience only mild symptoms, babesiosis can be severe — and even life-threatening — for older adults, individuals with weakened immune systems, or persons without a spleen.
With tick-borne illnesses becoming more prevalent, (including Lyme disease, anaplasmosis, ehrlichiosis, Rocky Mountain Spotted Fever, alpha-gal syndrome) protecting yourself and your loved ones from tick bites is critical. Knowing how babesiosis is contracted, recognizing symptoms and taking preventive steps are essential for staying safe outdoors.
What is Babesiosis?
Babesiosis is caused by a microscopic parasite that infects red blood cells, which carry oxygen throughout the body. Unlike bacteria or viruses, this parasite specifically attacks red blood cells, leading to extreme fatigue, weakness or serious illness in vulnerable people.
The parasite is mainly spread by the bite of an infected blacklegged tick, often called the deer tick (Ixodes scapularis). In some rare cases, it can be transmitted through blood transfusions or from a pregnant person to their baby.
Where is Babesiosis Found?
Babesiosis is mostly found in the Northeast and upper Midwest of the United States. In these regions, more and more cases are being reported every year. However, the disease appears to be spreading, partly because blacklegged ticks are living in more places due to habitat disruption and as the climate changes.
Symptoms of Babesiosis
Babesiosis symptoms typically appear one to four weeks after a tick bite, though some people may have none. Common signs include:
- Fever and chills
- Sweating
- Headache
- Body aches and joint pain
- Loss of appetite
- Fatigue
- Nausea
- Jaundice/dark-colored urine
Who is Most at Risk?
Some people are more likely to get very sick from babesiosis, including:
- Older adults, especially those over age 65
- People with weakened immune systems, such as those with cancer, HIV or who use certain medicines that make it harder to fight infections
- Anyone who does not have a spleen, an organ that helps filter blood and fight infections
The spleen is important because it helps your body get rid of the parasites that cause babesiosis. Without it, the body has a harder time fighting off these parasites.
If you are in one of these groups, it’s especially important to do regular tick checks, use tick repellent and avoid areas where ticks are common. If you notice any symptoms like fever, chills or fatigue after spending time outdoors, see a doctor right away and mention your higher risk for babesiosis. Early treatment can help prevent serious health problems.
Diagnosis and Treatment
Doctors diagnose babesiosis with blood tests that check for the parasite in your red blood cells by looking under a microscope or with special lab tests like PCR or antibody tests if the infection is hard to see.
Treatment usually combines two medicines: an antiparasitic drug and an antibiotic. Most people recover fully with this medicine, but those who are very sick or at high risk might need hospital care. In rare cases with severe illness, a blood exchange transfusion may be needed to help recovery.
The Blacklegged Tick: Multiple Diseases in One Bite
Blacklegged ticks can carry several pathogens, meaning a single bite may transmit multiple illnesses:
- Lyme disease: This is the most well-known tick-borne disease. It’s caused by bacteria and often (but not always) starts with a bullseye-shaped rash, and flu-like symptoms are common.
- Anaplasmosis: This is another bacterial infection that causes flu-like symptoms like fever and muscle aches.
- Babesiosis: A parasitic infection that attacks red blood cells.
- Ehrlichiosis: This bacterial infection also brings on symptoms like fever, headache and fatigue.
- Powassan virus: A rare but very serious virus that can affect the brain and nervous system.
Because ticks can carry multiple diseases, preventing or acting quickly after bites is crucial.
Preventing Babesiosis
The best defense is preventing tick bites:
- Cover up: Wear long sleeves, pants and tuck pants into socks.
- Use repellent: Apply U.S. Environmental Protection Agency-registered insect repellents tick repellents.
- Check yourself and pets: Inspect your body and pets after outdoor activities.
- Clean up: Showerimmediately after being outdoors and dry clothing on high heat for 15 minutes before washing it.
- Manage your yard: Keep lawns mowed and remove leaf litter.
Why Awareness Matters
Understanding babesiosis helps protect you and your community. Recognizing symptoms, practicing prevention and seeking prompt care reduce the risk of serious illness. Enjoy the outdoors safely by staying informed and tick-aware.
If you’re concerned about a recent tick bite, symptoms or exposure, schedule a consultation at the Stony Brook Regional Tick-Borne Disease Resource Center. For adult appointments at the clinic in Hampton Bays, please call (631) 725-2112. Children’s appointments can be scheduled at (631) 444-KIDS (5437).
Stony Brook’s specialized clinic, which is the first and only dedicated Tick-Borne Disease Clinic in the Northeast, provides:
- Infectious disease specialists who see adults and children on site
- Expert tick removal, diagnosis and treatment
- Convenient lab services/blood drawing
- Potential opportunity to participate in research studies
- Counseling on tick bite prevention, tick identification, tick removal kits and Tick-Borne Disease Reference Handbooks
