Beyond Lyme Disease: 5 Tick-Borne Infections Infectious Disease Specialists Are Seeing More Of

Lyme disease often steals the spotlight when we talk about tick-borne illness, but it's far from the only threat. As tick populations expand, infectious disease specialists are diagnosing a growing number of cases of other tick-borne infections. Understanding these illnesses—how to recognize them, diagnose them, and prevent them—can help you stay safer outdoors without unnecessary worry.

1. Anaplasmosis

Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum. It shares many symptoms with Lyme disease but can progress more rapidly if untreated.

• Where it's found: Mainly in the Northeast and Upper Midwest of the United States.
• How it spreads: Bites from infected black-legged ticks (the same ticks that carry Lyme).
• Symptoms:
  • Fever, chills, headache, muscle aches
  • Nausea, cough, confusion (in severe cases)
• Diagnosis:
  • Blood tests looking for low white-blood-cell counts and platelet counts
  • PCR (polymerase chain reaction) to detect bacterial DNA
• Treatment:
  • Doxycycline for adults and children of all ages
  • Usually 10–14 days; early treatment leads to rapid recovery
• Prevention:
  • Tick checks after outdoor activities
  • Wearing long sleeves and pants; using EPA-approved repellents

2. Babesiosis

Babesiosis is a malaria-like illness caused by the protozoan Babesia microti. It infects red blood cells and can cause severe anemia.

• Where it's found: Primarily in the Northeast and Upper Midwest, though cases are rising elsewhere.
• How it spreads: Often transmitted by the same ticks that carry Lyme and anaplasmosis; rare cases via blood transfusion.
• Symptoms:
  • Fever, chills, sweats, headache
  • Fatigue, muscle aches, nausea
  • Dark urine (sign of red-blood-cell breakdown)
• Diagnosis:
  • Blood smear to visualize parasites inside red blood cells
  • PCR testing for species identification
• Treatment:
  • Combination of atovaquone + azithromycin (mild to moderate cases)
  • Clindamycin + quinine (more severe cases)
• Who's at risk:
  • People without a spleen, the elderly, or those with weakened immune systems
• Prevention:
  • Same tick-bite precautions as for Lyme and anaplasmosis
  • Consider asking about blood screening in high-risk areas

3. Powassan Virus

Powassan virus is a rare but potentially severe flavivirus that can invade the brain (encephalitis).

• Where it's found: Northeastern states, the Great Lakes region, and some Canadian provinces.
• How it spreads: Black-legged ticks and groundhog ticks; transmission can occur within minutes of a bite.
• Symptoms:
  • Early: Fever, headache, vomiting, weakness
  • Later (in up to half of cases): Confusion, seizures, memory loss, coordination problems
• Diagnosis:
  • Blood or cerebrospinal fluid tests for antibodies against Powassan virus
• Treatment:
  • No specific antiviral therapy
  • Supportive care in hospital (e.g., IV fluids, respiratory support)
• Outlook:
  • About 10% mortality in severe cases
  • Long-term neurological problems common among survivors
• Prevention:
  • Extra vigilance in high-risk areas, especially during spring and summer
  • Check for small ticks; they can be as tiny as poppy seeds

4. Ehrlichiosis

Ehrlichiosis is usually caused by Ehrlichia chaffeensis and Ehrlichia ewingii. It often resembles anaplasmosis but is carried by a different tick species.

• Where it's found: Southeastern and south-central U.S., but cases are spreading.
• How it spreads: Bites from the lone star tick (Amblyomma americanum).
• Symptoms:
  • Fever, headache, fatigue, muscle aches
  • Rash (more common in children)
• Diagnosis:
  • Blood tests showing low white-blood-cell and platelet counts
  • PCR to detect Ehrlichia DNA
• Treatment:
  • Doxycycline (10–14 days)
  • Early treatment usually leads to full recovery
• Prevention:
  • Avoid dense underbrush and leaf litter where lone star ticks thrive
  • Use permethrin-treated clothing and insect repellent

5. Borrelia miyamotoi Disease (Relapsing Fever)

Borrelia miyamotoi is a cousin of the Lyme-causing bacterium but produces a relapsing fever illness.

• Where it's found: Northeastern U.S., Upper Midwest, parts of Europe and Asia.
• How it spreads: Black-legged ticks, the same ticks that carry Lyme and anaplasmosis.
• Symptoms:
  • High fever episodes lasting 1–5 days, then disappearing and returning
  • Headache, chills, muscle and joint aches
• Diagnosis:
  • Blood smear during fever episodes to look for spirochetes
  • PCR testing to confirm B. miyamotoi
• Treatment:
  • Doxycycline or amoxicillin (usually 10–14 days)
  • Hospitalization rare unless severe complications arise
• Prevention:
  • Standard tick-bite avoidance measures
  • Regular self-exams and prompt tick removal

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When to Seek Medical Care

Tick-borne illnesses can overlap in symptoms, making diagnosis tricky without medical testing. If you experience any of the following after a tick bite or time spent in tick-heavy areas, talk to your doctor:

• High fever or chills
• Severe headache or neck stiffness
• Unexplained rash (especially spreading or bull's-eye)
• Persistent muscle or joint pain
• Confusion, seizures, or neurological issues

It's important to note that while rashes are common with tick-borne diseases, if you develop a sudden rash with pustules or blister-like lesions—especially after starting a new medication—this could indicate a different condition entirely. You can use Ubie's free AI-powered symptom checker to learn more about Acute Generalized Exanthematous Pustulosis (AGEP) and determine if your symptoms match this drug-related reaction.

Always speak to a doctor if you suspect a serious or life-threatening condition. Early diagnosis and prompt treatment are the best ways to prevent complications.

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Practical Tips to Reduce Your Risk

• Wear long sleeves, long pants, and closed-toe shoes when hiking or gardening.
• Apply EPA-approved insect repellents containing DEET, picaridin, or IR3535.
• Treat clothing and gear with permethrin; wash and dry items according to label instructions.
• Perform thorough tick checks on yourself, your children, and pets after outdoor activities.
• Shower within two hours of coming indoors to wash off unattached ticks.

By staying informed about tick-borne illness beyond Lyme and taking simple prevention steps, you can enjoy the outdoors more safely. If you ever have concerns or worrisome symptoms, don't hesitate—speak with a healthcare professional right away.