Arm yourself against vector-borne disease

Optimized outcomes with increased awareness

The dry, mountainous geography of the American West is a limiting factor in the incidence of vector-borne illness; however, disease-carrying ticks and insects have gained a foothold due to changing weather patterns and international travel, introducing illness into previously unoccupied areas.

Among tick-borne illness in the West, Lyme disease and Rocky Mountain spotted fever occur most frequently. Spread by Ixodes ticks, Lyme disease causes fever, headache, fatigue, and a characteristic bulls-eye pattern rash. If left untreated, Lyme disease infections can spread to the joints, heart, and nervous system. Rocky Mountain spotted fever, carried by Dermacentor and Rhipicephalus species of ticks, causes severe symptoms including high fever, chills, headache, muscle aches, vomiting, and fatigue, and can lead to death if left untreated.

In the American West, the most encountered mosquito-borne diseases include West Nile virus, which is carried primarily by the Culex species of mosquito. Imported cases of dengue virus infection, carried by Aedes mosquitos, and malaria, which is transmitted by Anopheles mosquitos, can also be seen.1 According to the Centers for Disease Control and Prevention, both dengue virus and malaria diagnoses are most often made in individuals who’ve recently traveled internationally to endemic regions.2



According to data from the Centers for Disease Control and Prevention, cases of mosquito-borne disease in the Western United States are increasing. Our map highlights cases of mosquito-borne illness reported in 2004, 2011, and 2018.



The Centers for Disease Control and Prevention reports that across the Western United States, cases of tick-borne illness have risen substantially. Cases of tick-borne disease reported in 2004, 2011, and 2018 are demonstrated.


7,387 cases of West Nile virus reported in California from 2003–20213


46% increase in spotted fever rickettsiosis cases in the United States between 2016 and 20174,5

The right test, the right patient

For individuals suspected of having vector-borne infectious disease, early diagnosis and treatment are critical to prevent further harm. Mayo Clinic Laboratories’ arsenal of vector-borne disease testing includes serological and molecular evaluations for common and rare illness most prevalent in the Western U.S. Not only do we offer testing for individual disease states, such as newly released PCR testing for Powassan virus disease, but comprehensive panels that evaluate for a number of vector-borne conditions that present with similar symptoms.



  • Lyme disease
  • Rocky Mountain spotted fever (RMSF)
  • Babesiosis
  • Tularemia
  • Borrelia miyamotoi disease


  • West Nile virus
  • St. Louis encephalitis virus
  • Dengue virus (imported)
  • Malaria (imported)


  • Chagas disease (imported)

Check out our comprehensive vector-borne test offerings for a detailed look at available testing.

Learn more about how to order these tests at your institution.


  1. 2018-data.xlsx (
  2. CDC - Parasites - Malaria
  3. | California West Nile Virus Website
  4. Heitman  KN, Drexler  NA, Cherry-Brown D, Peterson AE, Armstrong PA, Kersch GJ. National surveillance data show increase in spotted fever rickettsiosis: United States, 2016-2017. Am J Public Health. 2019;109:719–21.
  5. Tick-borne Disease Working Group 2018 Report to Congress (