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Common Ticks of San Mateo County

Although there are 21 species of hard ticks in San Mateo County, the list below are the most common ticks that people and pets contact in the environment.

May contain: tick, animal, food, invertebrate, lobster, sea life, seafood, and insectGraphic that includes photos of 6 different ticks - males and females of three different species. Text lists the names of each of the species: Western blacklegged tick (Ixodes pacificus), Pacific Coast tick (Dermacentor occidentalis), American dog tick (Dermacentor variabilis)

 

Western Black-Legged Tick (Ixodes pacificus)

  • Adults quest along trails primarily November through April
  • Adults feed readily on humans, horses, dogs, and other large mammals
  • Larvae and nymphs are most active March to early August, peaking in April to June
  • Larvae and nymphs feed primarily on lizards but may also attach to rodents and people
  • Primary vector of Lyme disease to humans in California

 

Pacific Coast Tick (Dermacentor occidentalis)

  • Adults reach peak activity from April through May, but are present along trails from November through August
  • Adults feed on cattle, horses, deer, dogs, and humans
  • Larvae and nymphs are most active April through July
  • Larvae and nymphs feed on small rodents and other small mammals in spring and summer
  • Vector of tularemia and various uncommon Rickettsial diseases

 

American Dog Tick (Dermacentor variablis)

  • Adults quest along trails primarily from March through July
  • Adults feed on dogs and large mammals, including humans
  • Larvae and nymphs are most active April through July
  • Larvae and nymphs feed on rodents and other small mammals
  • Vector of tularemia and various uncommon Rickettsial diseases

 

Rarely, we receive a tick to identify that is a brown dog tick (Rhipicephalus sanguineus). To learn more about brown dog ticks, visit HERE or HERE.

 

 

 

Page last reviewed: July 15, 2024

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