What diseases do ticks carry? - briefly
Ticks transmit bacterial, viral, and protozoal agents including Borrelia burgdorferi (Lyme disease), Anaplasma phagocytophilum (anaplasmosis), Rickettsia species (spotted fever), Babesia microti (babesiosis), and Powassan virus. Geographic range and tick species dictate which pathogens are most common.
What diseases do ticks carry? - in detail
Ticks transmit a wide range of pathogens that cause serious human illness. The most common bacterial agents include Borrelia burgdorferi complex, the cause of Lyme disease, which presents with erythema migrans, fever, headache, and joint pain; Rickettsia rickettsii, responsible for Rocky Mountain spotted fever, characterized by high fever, rash, and vascular injury; Ehrlichia chaffeensis and Anaplasma phagocytophilum, producing ehrlichiosis and anaplasmosis with symptoms of fever, leukopenia, and thrombocytopenia; Francisella tularensis, the agent of tularemia, leading to ulceroglandular lesions and systemic infection; and Coxiella burnetii, causing Q fever, which may manifest as atypical pneumonia and hepatitis.
Protozoan infection is chiefly represented by Babesia microti, the cause of babesiosis, a malaria‑like disease marked by hemolytic anemia, fever, and chills, especially severe in immunocompromised patients.
Viral threats transmitted by ticks comprise several encephalitides and hemorrhagic fevers. Tick‑borne encephalitis virus (TBEV) induces a biphasic illness with meningitis or encephalitis; Crimean‑Congo hemorrhagic fever virus (CCHFV) leads to severe hemorrhagic syndrome and high mortality; Powassan virus causes encephalitis with rapid neurological decline; Heartland virus and Bourbon virus, both emerging in North America, produce fever, fatigue, and leukopenia.
Key vectors differ by region. In North America, Ixodes scapularis and Ixodes pacificus spread Lyme disease, anaplasmosis, and babesiosis; Dermacentor variabilis and Dermacentor andersoni transmit Rocky Mountain spotted fever and tularemia. In Europe and Asia, Ixodes ricinus and Ixodes persulcatus carry Lyme disease, TBEV, and anaplasmosis. Amblyomma americanum (lone‑star tick) is linked to ehrlichiosis and the emerging Heartland virus.
Transmission occurs during prolonged attachment, typically ≥24 hours for bacterial agents, while some viruses can be transmitted within minutes of feeding. Prompt removal of attached ticks reduces infection risk. Early diagnosis relies on clinical presentation, exposure history, and laboratory testing (serology, PCR, blood smear). Effective treatment includes doxycycline for most bacterial infections, supportive care for viral illnesses, and antiprotozoal regimens (atovaquone plus azithromycin) for babesiosis.
Awareness of regional tick species, their seasonal activity, and the specific pathogens they carry is essential for preventing and managing tick‑borne diseases.