What types of ticks are there and how are they dangerous? - briefly
Ticks are divided into hard ticks (family Ixodidae) and soft ticks (family Argasidae), both capable of transmitting bacteria, viruses, and protozoa. Hard ticks remain attached for days and commonly spread Lyme disease, Rocky Mountain spotted fever, and anaplasmosis, whereas soft ticks feed briefly and can transmit relapsing fever and other infections.
What types of ticks are there and how are they dangerous? - in detail
Ticks belong to two principal families: hard ticks (Ixodidae) and soft ticks (Argasidae). Hard ticks possess a scutum, feed for several days, and are the primary vectors of bacterial, viral, and protozoal diseases. Soft ticks lack a scutum, feed for minutes to hours, and transmit a narrower range of pathogens.
Hard tick species of medical importance
- Ixodes scapularis (black‑legged or deer tick) – transmits Borrelia burgdorferi (Lyme disease), Anaplasma phagocytophilum (anaplasmosis), and Babesia microti (babesiosis).
- Ixodes ricinus (European castor‑bean tick) – vector for Lyme disease, tick‑borne encephalitis virus, and Rickettsia spp.
- Dermacentor variabilis (American dog tick) – carries Rickettsia rickettsii (Rocky Mountain spotted fever) and Francisella tularensis (tularaemia).
- Dermacentor andersoni (Rocky Mountain wood tick) – also a vector for R. rickettsii and Anaplasma marginale.
- Amblyomma americanum (Lone‑star tick) – associated with Ehrlichia chaffeensis (ehrlichiosis), Francisella spp., and the alpha‑gal allergy.
- Rhipicephalus sanguineus (brown dog tick) – spreads Rickettsia conorii (Mediterranean spotted fever) and Ehrlichia canis.
Soft tick species of medical importance
- Argas persicus (fowl tick) – can transmit Borrelia anserina (avian spirochetosis).
- Ornithodoros spp. (including O. moubata and O. hermsi) – vectors for tick‑borne relapsing fever spirochetes and, in some regions, tick‑borne encephalitis virus.
Health risks linked to tick feeding
- Pathogen transmission through saliva that contains anticoagulants, immunomodulators, and anti‑inflammatory agents, facilitating infection during prolonged attachment.
- Co‑feeding transmission, where uninfected ticks acquire pathogens from nearby infected ticks without systemic host infection.
- Tick‑induced paralysis caused by neurotoxins released during feeding; symptoms resolve after tick removal.
- Localized allergic reactions, including erythema migrans (characteristic rash of Lyme disease) and hypersensitivity to tick salivary proteins.
Understanding species distribution, host preferences, and seasonal activity patterns enables targeted prevention and prompt identification of tick‑borne illnesses.