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Tick-borne Diseases

Lyme Disease

  • Lyme Disease, also known as Lyme Borreliosis, is the number one tick-borne disease transmitted in California with an average of 200 cases per year.
  • This disease is caused by the bacterial spirochete, Borrelia burgdorferi.
  • Incubation: period 3 to 30 days.
  • Acute Symptoms (within a few weeks):
    • Flu-like symptoms.
    • About 60% of adults develop a slowly enlarging red rash; less likely in children.
  • Chronic Symptoms (months to years later):
    • Arthritis with joint swelling.
    • Migrating pain in joints, muscles and bones.
    • Nervous system disorders.
  • Susceptibility: It affects all ages.
  • Diagnosis: By physician with blood test and /or observation of rash by physician.
  • Treatment: Treatment with antibiotics.
  • Tick vectors: Western Black-legged Tick, (Ixodes pacificus)

Known Occurrences in Napa County

Lyme disease is present in Napa County.  There have been 13 diagnosed cases between 2000 and 2010.


Rocky Mountain Spotted Fever

  • Also known as tick-borne typhus fever is a rare tick-borne disease in California.
  • Disease is caused by the bacterium, Rickettsia rickettsii.
  • Incubation: period 3 to 14 days.
  • Symptoms:
    • Moderate to high fever for 2-3 weeks.
    • Reddish-purple spots on extremities by third day of fever, which spreads rapidly to most of the body.
  • Susceptibility: It affects all ages.
  • Diagnosis: By physician with blood test.
  • Treatment: Treatment with antibiotics.  There is a 4% fatality rate with treatment, 15-20% fatality rate without treatment.
  • Tick vectors:
    • Pacific Coast Tick, (Dermacentor occidentalis)
    • Rocky Mountain Wood Tick, (Dermacentor andersoni)

Known Occurrences in Napa County

Rocky Mountain Spotted Fever is present in Napa County.  There was one case reported by the California Department of Health Services in 2000.

Tick Paralysis

  • Disease is caused by the toxins in tick saliva and can occur when the tick remains continuously attached for 2-7 days.
  • Incubation: period up to 35 days.
  • Symptoms:
    • Irritability
    • Weakness
    • Paralysis – Paralysis begins about one day after the onset of the other symptoms, starting with the legs and feet and moving to the arms and back.
  • Susceptibility: Effects all ages, children are the most susceptible.
  • Diagnosis: By finding the attached tick, usually on scalp or rear neck area near base of head.
  • Treatment: Removal of the tick. Recovery usually occurs within 48 hours.
  • Tick vectors:
    • American Dog Tick, (Dermacentor variabilis)
    • Rocky Mountain Wood Tick, (Dermacentor andersoni)

Known Occurrences in Napa County

Tick vector is present in the County, no known diagnosed cases.

Tularemia

  • Tularemia, also known as rabbit fever or deerfly fever, is a rare tick-borne disease in California.
  • This disease is caused by the bacterium, Francisella tularensis.  It can also be caused by the bites of deerflies, mosquitoes and infected mammals, and by ingestion of contaminated meat or water.
  • Incubation: period 2 to 10 days.
  • Symptoms:
    • Painless open sore or ulcer usually at the site of the tick bite.
    • Swelling of lymph nodes
    • Chills and fever
    • Weakness.
    • Loss of appetite.
  • Diagnosis: With blood test by physician.
  • Treatment: With antibiotics.  Fatality rate 5-10% if untreated.
  • Tick vectors:
    • American Dog Tick, (Dermacentor variabilis)
    • Rocky Mountain Wood Tick, (Dermacentor andersoni)

Known Occurrences in Napa County

Tick vector is present in Napa County.  One diagnosed case confirmed in American Canyon in 2010.


For more information about these diseases go to the Centers for Disease Control.