The following link is to a table showing plague-positive rodents tested in conjunction with the California Department of Public Health, Vector-borne Disease Section Plague Surveillance Program.

Plague-positive rodents 2008

The following table contains the results of tests for evidence of Borrelia infection in ticks collected in California in 2008. The tests were conducted by the California Department of Public Health, Vector-Borne Disease Section (CDPH-VBDS), and by the United States Army Center for Health Promotion and Preventive Medicine - West (US Army).

In 2007, 482 blood samples were collected from wild carnivores and 914 blood samples from wild rodents in connection with the statewide plague surveillance program conducted by the Vector-borne Disease Section of the California Department of Public Health. Veterinarians submitted 5 samples from domestic pets. Plague was confirmed in one domestic cat from Kern County. Plague antibodies were detected in 37 of 335 coyotes, 12 of 47 black bears, and one of 4 gray foxes. Among wild rodents, antibodies were detected in 23 of 432 California ground squirrels, and one of 237 chipmunks. Additionally, samples from 124 feral pigs were negative. All data from 2007 Annual Report, Vector-Borne Disease Section, California Department of Public Health.

The California Department of Public Health routinely tests various types of animals for evidence of infection by plague bacilli. The map displays data for 2004 for tests on carnivores, rodents, and pets.

Human granulocytic anaplasmosis (HGA) is an infection caused by the bacteria Anaplasma phagocytophilum. HGA bacteria infect the whte blood cells of their hosts, specifically a group of cells called granulocytes. People acquire HGA in California, when they are bitten with a western black-legged tick (Ixodes pacificus) infected with HGA bacteria.

Rocky Mountain spotted fever (RMSF) is a serious disease caused by Rickettsia rickettsii bacteria and transmitted to people by ticks, principally the Rocky Mountain wood tick, Dermacentor andersoni and the American dog tick Dermacentor variabilis. In California, RMSF is a rare disease, with only 1 to 3 cases reported per year; most cases are reported from the south Atlantic region of the United States.

Additional information on RMSF can be found at the Center for Disease Control and Prevention website:

Tickborne relapsing fever (TBRF) is a bacterial disease transmitted to people by soft ticks in the genus Ornithodoros. TBRF is a rare disease in California with between 1 and 8 cases reported per year, generally during the summer months. People are at risk of contracting TBRF when they sleep in rustic mountain cabins that are infested with wild rodents. The soft ticks that transmit TBRF feed rapidly; most people who contract TBRF have no recollection of a tick bite.

Ticks are the vectors of a large number of disease-causing agents in California. While Lyme disease is by far the most common tickborne disease of people in the United States and California, ticks also transmit the organisms that cause tickborne relapsing fever, Rocky Mountain spotted fever, tularemia, anaplasmosis, human ehrlichiosis, and babesiosis.  In addition, people and domestic animals can develop tick paralysis following a tick bite.

 

 

Malaria is not endemic to California. But on occasion, imported malaria resulted in local outbreaks. The map below illustrates those transmissions where 10 or more cases resulted.