Time of year and outdoor recreation affect human exposure to ticks in California, United States

Daniel J. Salkeld, W. Tanner Porter, Samantha M. Loh, Nathan C. Nieto

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Interactions between humans and ticks are often measured indirectly, using surveillance of tick population abundance and pathogen prevalence, or reported human disease data. We used data garnered as part of a free national citizen science research effort to describe actual human exposures to ticks in California. Human-biting ticks (n = 1,905) submitted for identification were predominantly western black-legged ticks (Ixodes pacificus) (68%), American dog ticks (Dermacentor variabilis) (24%), and Pacific Coast ticks (Dermacentor occidentalis) (7%). Tick exposure occurred predominantly during recreational use of the outdoors, rather than exposure near the home environment. Tick submissions peaked in May, but human exposure to ticks occurred throughout the year. Adult I. pacificus were most frequently found on humans during March-May, though previous research demonstrates that questing adults on vegetation are more abundant earlier in the winter.

Original languageEnglish (US)
Pages (from-to)1113-1117
Number of pages5
JournalTicks and Tick-borne Diseases
Issue number5
StatePublished - Aug 2019


  • California Lyme disease
  • Citizen science
  • Tick phenology
  • Tick seasonality
  • Vector surveillance

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Insect Science
  • Infectious Diseases


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