What diseases do ticks transmit? - briefly
Ticks act as vectors for a range of bacterial, viral, and protozoan infections. Notable illnesses include Lyme disease, Rocky Mountain spotted fever, anaplasmosis, ehrlichiosis, babesiosis, tick‑borne encephalitis, Powassan virus, and Colorado tick fever.
What diseases do ticks transmit? - in detail
Ticks are vectors for a wide range of pathogens that affect humans and animals. The most clinically significant agents fall into three categories: bacteria, viruses, and protozoa.
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Borrelia burgdorferi complex – causative agent of Lyme disease. Transmitted primarily by Ixodes scapularis in North America and Ixodes ricinus in Europe. Early manifestations include erythema migrans and flu‑like symptoms; later stages may involve arthritis, facial palsy, and neurocognitive deficits.
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Anaplasma phagocytophilum – agent of human granulocytic anaplasmosis. Carried by Ixodes species. Presents with fever, headache, myalgia, and leukopenia; severe cases can progress to organ dysfunction.
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Ehrlichia chaffeensis – responsible for human monocytic ehrlichiosis. Transmitted by Amblyomma americanum (lone‑star tick). Symptoms include fever, rash, and thrombocytopenia; untreated infection may be fatal.
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Rickettsia rickettsii – causes Rocky Mountain spotted fever. Vector is Dermacentor variabilis or Dermacentor andersoni. Hallmarks are high fever, headache, and a petechial rash that typically starts on the wrists and ankles.
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Rickettsia parkeri – produces a milder spotted fever transmitted by Amblyomma maculatum. Features include fever, eschar at the bite site, and a localized rash.
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Rickettsia slovaca – associated with tick‑borne lymphadenopathy (TIBOLA). Transmitted by Dermacentor marginatus in Europe; results in scalp eschar and cervical lymphadenopathy.
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Babesia microti – protozoan that causes babesiosis. Ixodes scapularis is the primary vector in the United States. Clinical picture resembles malaria: hemolytic anemia, fever, and chills; severe disease may affect the elderly or immunocompromised.
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Babesia divergens – European counterpart of babesiosis, transmitted by Ixodes ricinus. Leads to similar hemolytic syndrome, often severe in splenectomized patients.
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Francisella tularensis – agent of tularemia. Transmitted by Dermacentor, Amblyomma, and other genera. Presents as ulceroglandular, pneumonic, or typhoidal forms depending on route of infection.
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Powassan virus – flavivirus spread by Ixodes ticks in North America and parts of Eurasia. Causes encephalitis or meningitis; mortality rates can reach 10 % and survivors may suffer long‑term neurologic deficits.
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Tick‑borne encephalitis virus (TBEV) – flavivirus endemic to Europe and Asia, transmitted by Ixodes ricinus and Ixodes persulcatus. Biphasic illness with initial flu‑like phase followed by neurologic involvement (meningitis, encephalitis, or myelitis).
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Coxiella burnetii – occasionally transmitted by ticks, contributing to Q fever outbreaks. Leads to febrile illness, pneumonia, or chronic endocarditis.
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Bartonella henselae – implicated in cat‑scratch disease and, less frequently, tick‑borne bacillary angiomatosis. Vectors include various tick species in temperate regions.
Geographic distribution varies: Ixodes‑borne agents dominate temperate zones of North America and Europe; Amblyomma species spread many pathogens across the southeastern United States and parts of Central and South America; Dermacentor ticks are common in mountainous regions of the western United States and Eurasia.
Prevention relies on personal protective measures, habitat management, and prompt removal of attached ticks. Early recognition of specific symptom patterns, combined with appropriate laboratory testing, enables targeted antimicrobial or antiviral therapy, reducing morbidity and mortality associated with these tick‑borne infections.