How many diseases do ticks transmit? - briefly
Ticks transmit over 30 distinct bacterial, viral, and protozoan diseases to humans, including Lyme disease, Rocky Mountain spotted fever, anaplasmosis, babesiosis, and several viral encephalitides.
How many diseases do ticks transmit? - in detail
Ticks act as vectors for more than thirty distinct human diseases worldwide. The spectrum includes bacterial, viral, and protozoan infections, each with specific geographic hotspots and clinical manifestations.
- Lyme disease – caused by Borrelia burgdorferi; prevalent in North America and Europe; early symptoms include erythema migrans, fever, and fatigue; later stages may involve arthritis and neurological deficits.
- Anaplasmosis – Anaplasma phagocytophilum infection; common in the United States and parts of Europe; presents with fever, leukopenia, and thrombocytopenia.
- Ehrlichiosis – Ehrlichia chaffeensis and related species; primarily in the southeastern United States; characterized by fever, headache, and muscle aches.
- Babesiosis – protozoan Babesia microti; endemic in the northeastern United States and parts of Asia; can cause hemolytic anemia, jaundice, and severe organ dysfunction in immunocompromised patients.
- Rocky Mountain spotted fever – Rickettsia rickettsii; concentrated in the central and southeastern United States; marked by fever, rash, and potential vascular injury.
- Tick-borne relapsing fever – various Borrelia spp.; occurs in Africa, Europe, and the Americas; features recurrent fever episodes separated by afebrile periods.
- Tularemia – Francisella tularensis; found across the Northern Hemisphere; manifests as ulceroglandular, pneumonic, or systemic disease depending on entry route.
- Powassan virus disease – flavivirus; limited to North America and Russia; can cause encephalitis and meningitis with high mortality rates.
- Crimean‑Congo hemorrhagic fever – Nairovirus; widespread in Africa, the Balkans, the Middle East, and Asia; produces severe hemorrhagic fever with a case‑fatality rate up to 40 %.
- Tick-borne encephalitis – TBE virus; prevalent in Europe and Asia; leads to biphasic illness with meningitis, encephalitis, or meningoencephalitis.
- Southern tick‑associated rash illness (STARI) – Borrelia lonestari suspected; limited to the southeastern United States; presents with a rash similar to Lyme disease.
- Colorado tick fever – Colorado tick fever virus; occurs in the Rocky Mountain region; causes febrile illness with possible hemorrhagic complications.
- Heartland virus disease – Heartland virus; identified in the Midwestern United States; results in fever, leukopenia, and thrombocytopenia.
- Bourbon virus disease – Bourbon virus; reported in the United States; produces fever, myalgia, and sometimes severe systemic illness.
- Severe fever with thrombocytopenia syndrome (SFTS) – SFTS virus; endemic in East Asia; characterized by high fever, thrombocytopenia, and multi‑organ failure.
Additional pathogens transmitted by ticks include Rickettsia parkeri (American spotted fever), Rickettsia slovaca (tick‑borne lymphadenopathy), Coxiella burnetii (Q fever), Bartonella henselae (cat‑scratch disease variant), and several Anaplasma and Ehrlichia species affecting animals and occasionally humans. The total count of recognized tick‑borne human diseases exceeds thirty, with ongoing research identifying new agents regularly. Understanding regional tick species, host reservoirs, and seasonal activity patterns is essential for accurate risk assessment and preventive strategies.