[HideMe]Tickborne Diseases

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.

Photo credit Edman/McClelland Collection

[HideMe]Lyme disease

Lyme disease is a tickborne disease caused by the bacteria Borrelia burgdorferi.  It was first identified in California in 1978 from a Sonoma County hiker.  While incidence of Lyme disease (number of cases adjusted per population) is highest in the northwestern part of the state, human cases have been reported from many regions of California.

In California, the western black-legged tick, Ixodes pacificus, is the only tick that transmits Lyme disease to people.  This tick has three life stages, a larval, nymphal and adult stage.  People become infected with Lyme disease via the bite of an adult female or a nymphal western-black legged tick.  Infection prevalences of B. burgdorferi in the western black-legged tick are approximately 1-2% in adults, 2-15% in nymphs, and 0% in larvae.  People are at highest risk of acquiring Lyme disease from nymphal ticks due to their small size and higher infection prevalence. Lyme disease is most commonly reported in spring and early summer in California, when nymphal ticks are most abundant.  Adult western black-legged ticks are most active in fall and winter.

For more information on Lyme disease, please visit the California Department of Public Health website at: http://www.cdph.ca.gov/healthinfo/discond/Pages/LymeDisease.aspx

Ixodes pacificus ticks tested for evidence of Borrelia species, California, 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).

 

County
Location

Ticks
tested

Pools
tested
Number Pools Positive
 
DFA
PCR**
Laboratory
Borrelia
spp.
Borrelia spp. Borrelia burgdorferi  
Alameda Indian Joe Trail
25
25
0
    CDPH-VBDS
Little Yosemite Area
4
4
0
    CDPH-VBDS
Amador Grinding Rock SP
31
4
 
1
  US Army
Calveras Natural Bridge
103
11
      US Army
Water Treatment Site
13
4
 
40
  US Army
Contra Costa Tilden Regional Park
115 (170*)
115 (170*)
1 (4*)
    CDPH-VBDS
Lake Mendocino NF
190 (2*)
19 (1*)
 
4
3
US Army
Middletown
5 (3*)
5 (3*)
0
    CDPH-VBDS
Los Angeles Angeles NF
17
17
0
    CDPH-VBDS
Charmlee Wilderness
117
117
0
    CDPH-VBDS
Malibu
100
10
 
0
  US Army
Madera Chepo Saddle
2 (1*)
1 (1*)
 
0
  US Army
Marin Point Reyes NS
5
5
0
    CDPH-VBDS
Marin Headlands
67
67
3
    CDPH-VBDS
Mariposa Sierra NF
20
2
 
0
  US Army
Mendocino Manchester SB
26
26
0
    CDPH-VBDS
Nevada Nevada City
17 (8*)
11 (2*)
 
0
  US Army
Riverside San Bernardino NF
26 (1*)
26 (1*)
0
    CDPH-VBDS
San Bernardino San Bernardino NF
6
2
 
0
  US Army
San Diego Cleveland NF
24
3
 
0
  US Army
Cleveland NF
23
23
0
    CDPH-VBDS
San Joaquin Carnigie SP
22
8
 
0
  US Army
Santa Clara Henry Coe SP
100 (11*)
10 (1*)
 
2 (1*)
2 (1*)
US Army
Shasta Anderson River Park
38
4
 
0
  US Army
Baily Cove CG
18
2
 
0
  US Army
Anderson
51
5
 
0
  US Army
Redding
70
7
 
0
  US Army
Stanislaus Patterson
3
2
 
0
  US Army
Total ticks tested
1,238 (196*)
535 (179*)
       
Total pools positive    
4 (4*)
11 (1*)
5 (1*)
 

 

* Nymphs; ** PCR primer sets were specific for B. burgdorferi;

Tests: DFA, Direct Fluorescent Antibody; PCR, Polymerase Chain Reaction;

CG, Campground; NF, National Forest; NS, National Seashore; SB, State Beach; SP, State Park;

Anaplasmosis

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.

For more information on Anaplasmosis, please visit the California Department of Public Health http://www.cdph.ca.gov/healthinfo/discond/Pages/Anaplasmosis.aspx

Rocky Mountain Spotted Fever

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:

http://www.cdc.gov/ncidod/dvrd/rmsf/index.htm

as well as at the California Department of Public Health website: http://www.cdph.ca.gov/healthinfo/discond/Pages/RockyMountainSpottedFever.aspx

Tick-bite Prevention PSA Contest


A Dermacentor tick
 
The California Department of Public Health and the DEET Education
Program are excited to announce the launch of our Tick-bite Prevention
Video Public Service Announcement (PSA) Contest!  The purpose of the
contest is to create short video public service announcements to help
people understand how to prevent tick-bites.
 
The contest is open to California residents only. There are two age and
award categories for the Video PSA:
 
1) 17 and younger
 
2) 18 and older 
 
The first place winner in both categories will receive $350 and an award certificate.
The winning videos may be featured on broadcast TV and/or radio and on government
and partner websitesand will remain available on YouTube. The winners may be invited
to press events and/or asked to appear in futurecontest promotional videos. Other 
awards certificates will be issued for winners receivingsecond or third place or honorable
mention.
 
Complete contest rules and entry forms can be found at: 
http://www.deetonline.org/CDPHvideocontest/
<http://www.deetonline.org/CDPHvideocontest/> . Entries are being
accepted through April 1, 2011.
 
We would like to ask for your assistance is distributing the information throughout California.
Please forward this entire email and attachment to any and all individuals and organizations who
may be interested.We are especially interested in getting the information into the hands of some
our incredibly talented young adultsand school children California.
If you have questions, please contact:
 
Claudia J. Erickson, MS, CHES 
Health Education & Communication Specialist 
Veterinary Public Health Section 
CA Department of Public Health 
(916) 552-9762 claudia.erickson@cdph.ca.gov <mailto:claudia.erickson@cdph.ca.gov>  
  
 

Tickborne Relapsing Fever

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.

For more information on Tickborne relapsing fever, please visit the California Department of Public Health website: http://www.cdph.ca.gov/healthinfo/discond/Pages/Tick-BorneRelapsingFever.aspx