What do ticks cause in humans? - briefly
Ticks act as vectors for bacterial, viral, and protozoan agents that cause illnesses such as Lyme disease, Rocky Mountain spotted fever, anaplasmosis, and babesiosis. They can also produce localized skin irritation and allergic reactions at the bite site.
What do ticks cause in humans? - in detail
Ticks transmit a range of pathogens that produce acute and chronic illnesses in people. The most common conditions include:
- Lyme disease – caused by Borrelia burgdorferi; early signs are erythema migrans rash, fever, headache, fatigue; later stages may involve arthritis, facial palsy, and neurocognitive deficits.
- Anaplasmosis – infection with Anaplasma phagocytophilum; symptoms comprise fever, chills, muscle aches, and leukopenia; prompt antibiotic therapy prevents severe complications.
- Babesiosis – protozoan Babesia microti infection; presents with hemolytic anemia, jaundice, and high fever; can be life‑threatening in immunocompromised hosts.
- Rocky Mountain spotted fever – Rickettsia rickettsii; characterized by fever, headache, rash that spreads from wrists and ankles to trunk, and potential vascular damage.
- Ehrlichiosis – caused by Ehrlichia chaffeensis; manifests as fever, malaise, muscle pain, and thrombocytopenia; early treatment reduces risk of organ failure.
- Tularemia – Francisella tularensis infection; produces ulcerative skin lesions, lymphadenopathy, and pneumonia when inhaled.
- Tick‑borne encephalitis (TBE) – viral infection of the central nervous system; initial flu‑like phase may progress to meningitis, encephalitis, or paralysis.
- Powassan virus disease – rare flavivirus; leads to encephalitis or meningitis with high mortality and long‑term neurological impairment.
Beyond infectious diseases, tick bites can cause local reactions such as:
- Allergic dermatitis – redness, swelling, and itching at the bite site.
- Alpha‑gal syndrome – delayed anaphylaxis to mammalian meat after sensitization to the carbohydrate galactose‑α‑1,3‑galactose present in tick saliva.
Severity depends on tick species, geographic region, duration of attachment, and host immune status. Prompt removal of attached ticks reduces pathogen transmission risk; most bacteria require 24–48 hours of feeding before entering the bloodstream. Early diagnosis, typically based on clinical presentation and laboratory confirmation, enables effective antimicrobial or supportive treatment, limiting morbidity and preventing long‑term sequelae.