Which diseases can ticks transmit? - briefly
Ticks transmit bacterial infections (e.g., Lyme disease, Rocky Mountain spotted fever, ehrlichiosis), viral diseases (e.g., Powassan virus), and protozoal illnesses (e.g., babesiosis).
Which diseases can ticks transmit? - in detail
Ticks serve as vectors for a diverse array of pathogens. The most clinically significant agents are listed below, each accompanied by the responsible tick species, geographic range, and typical manifestations.
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Lyme disease – bacterium Borrelia burgdorferi (and related species). Transmitted primarily by Ixodes scapularis in eastern North America and Ixodes pacificus on the West Coast, as well as Ixodes ricinus in Europe and Asia. Early signs include erythema migrans, fever, headache, and fatigue; later stages may involve arthritis, neuroborreliosis, and cardiac conduction defects.
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Rocky Mountain spotted fever – Rickettsia rickettsii. Vectors: Dermacentor variabilis (eastern U.S.), Dermacentor andersoni (Rocky Mountain region). Symptoms: abrupt fever, severe headache, rash that begins on wrists and ankles and spreads centrally, possible vasculitis leading to organ failure.
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Anaplasmosis – Anaplasma phagocytophilum. Transmitted by Ixodes scapularis and Ixodes pacificus. Presents with fever, chills, myalgia, leukopenia, and thrombocytopenia; can progress to respiratory distress or multi‑organ dysfunction.
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Ehrlichiosis – Ehrlichia chaffeensis (human monocytic) and Ehrlichia ewingii. Vector: lone‑star tick (Amblyomma americanum). Clinical picture: fever, headache, malaise, leukopenia, elevated liver enzymes; severe cases may develop hemorrhage or meningoencephalitis.
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Babesiosis – protozoan Babesia microti (U.S.) and Babesia divergens (Europe). Transmitted by Ixodes spp. Causes hemolytic anemia, fever, chills, and jaundice; high‑risk patients (splenectomized, elderly) may experience severe hemolysis and renal failure.
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Tularemia – bacterium Francisella tularensis. Vectors include Dermacentor and Amblyomma ticks. Presents as ulceroglandular lesions, pneumonic form, or typhoidal fever; mortality without treatment can reach 30 % for certain subspecies.
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Q fever – Coxiella burnetii. Transmitted by Amblyomma and Rhipicephalus ticks. Acute infection yields fever, hepatitis, and pneumonia; chronic disease may cause endocarditis.
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Tick‑borne encephalitis (TBE) – flavivirus TBEV. Vectors: Ixodes ricinus (Europe) and Ixodes persulcatus (Siberia, Far East). Biphasic illness: initial flu‑like phase, followed by neurologic involvement (meningitis, encephalitis, or myelitis).
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Crimean‑Congo hemorrhagic fever (CCHF) – Nairovirus CCHFV. Transmitted by Hyalomma ticks across Africa, the Balkans, the Middle East, and Central Asia. Early fever progresses to hemorrhagic syndrome, hepatic failure, and high mortality (≈30 %).
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Powassan virus – flavivirus. Vectors: Ixodes spp. Rare but severe; causes encephalitis, seizures, and long‑term neurologic deficits.
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Heartland virus – Bunyavirus species. Vector: Amblyomma americanum in the United States. Symptoms: fever, fatigue, thrombocytopenia, leukopenia; some patients develop severe illness requiring intensive care.
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Bourbon virus – Thogotovirus species. Transmitted by Amblyomma americanum. Clinical picture resembles other tick‑borne febrile illnesses; limited data on outcomes.
These pathogens represent the core spectrum of tick‑borne disease. Diagnosis relies on clinical suspicion, epidemiologic exposure, and laboratory confirmation (serology, PCR, culture). Prompt antimicrobial therapy (doxycycline for most bacterial infections) or supportive care for viral and protozoal illnesses reduces morbidity and mortality.