What diseases can result from a tick bite and what symptoms appear in humans? - briefly
Tick bites can transmit diseases such as Lyme disease (fever, fatigue, erythema migrans rash, joint pain), Rocky Mountain spotted fever (high fever, headache, rash), Anaplasmosis (fever, chills, muscle aches), Babesiosis (hemolytic anemia, chills, fever), Ehrlichiosis (fever, rash, leukopenia), and Tick‑borne encephalitis (headache, neck stiffness, neurological deficits).
What diseases can result from a tick bite and what symptoms appear in humans? - in detail
Tick bites can transmit a variety of infectious agents, each producing a characteristic clinical picture. The most frequently encountered illnesses include:
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Lyme disease – caused by Borrelia burgdorferi. Early signs: erythema migrans rash expanding from the bite site, fever, chills, headache, fatigue, and arthralgia. If untreated, disseminated disease may cause multiple erythema migrans lesions, meningitis, facial palsy, carditis, and migratory joint swelling. Late manifestations often involve chronic arthritis, especially of the knees, and neurocognitive deficits.
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Rocky Mountain spotted fever – infection with Rickettsia rickettsii. Typical onset 2–14 days after exposure. Presents with abrupt fever, severe headache, myalgia, and a maculopapular rash that begins on wrists and ankles before spreading centrally, sometimes involving the palms and soles. Complications include vasculitis, hypotension, organ failure, and, without timely doxycycline therapy, mortality rates up to 20 %.
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Ehrlichiosis – caused by Ehrlichia chaffeensis or related species. Symptoms appear 5–10 days post‑bite and include fever, chills, malaise, myalgia, headache, and leukopenia. Laboratory findings often reveal thrombocytopenia, elevated liver enzymes, and occasional rash. Severe cases progress to hemorrhagic complications, respiratory distress, or multiorgan dysfunction.
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Anaplasmosis – Anaplasma phagocytophilum infection. Clinical picture mirrors ehrlichiosis: fever, chills, myalgia, headache, and laboratory evidence of leukopenia, thrombocytopenia, and transaminase elevation. Neurological involvement is rare but possible.
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Babesiosis – protozoan Babesia microti transmitted primarily by Ixodes ticks. Initial manifestations: hemolytic anemia, fever, chills, sweats, myalgia, and fatigue. Severe disease may lead to jaundice, renal failure, and respiratory distress, particularly in immunocompromised hosts or splenectomized patients.
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Tick‑borne relapsing fever – Borrelia spp. (e.g., B. hermsii). Characterized by recurrent febrile episodes lasting 2–5 days, interspersed with afebrile periods. Accompanied by headache, myalgia, arthralgia, and sometimes a petechial rash.
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Tularemia – caused by Francisella tularensis. After a bite, patients develop sudden high fever, ulceroglandular lesions with painful regional lymphadenopathy, and occasionally pneumonia or systemic sepsis.
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Powassan virus infection – a flavivirus. Early symptoms: fever, headache, vomiting, and weakness; neurological involvement may appear within days, presenting as encephalitis, meningitis, or acute flaccid paralysis. Mortality rates reach 10 %, with long‑term neurologic deficits in survivors.
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Southern tick‑associated rash illness (STARI) – resembles early Lyme disease with a circular erythematous lesion at the bite site, low‑grade fever, fatigue, and mild arthralgia. The causative agent remains uncertain; symptoms typically resolve spontaneously.
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Alpha‑gal syndrome – delayed IgE‑mediated allergy to mammalian meat triggered by tick saliva. Onset 3–6 hours after ingestion of red meat, presenting with urticaria, angioedema, gastrointestinal upset, and, in severe cases, anaphylaxis.
Recognition of these patterns demands prompt laboratory confirmation (serology, PCR, blood smear, or culture) and early antimicrobial therapy, most commonly doxycycline for bacterial agents. Delays increase the risk of complications, organ injury, and mortality.