San Mateo County: Ticks and Lyme Disease

Entomology Report November 2008, San Mateo County Mosquito and Vector Control District

In November, district staff began annual surveillance activities for Lyme disease bacteria in ticks. This year, the program will focus on surveying sites of potential risk that have not been thoroughly evaluated in the past. Tick surveys were conducted this month in Portola Valley Ranch and on a previously unsurveyed trail in Laurelwood Park (San Mateo). The western black-legged tick is the primary vector of the Lyme disease spirochete in California. Adults of this tick begin appearing on trails in November, reach peak abundance in January-February and persist into early May. The immature stage (nymph) reaches peak abundance in April-May and is found in dense hardwood forest. Nymphs present a higher risk for transmitting Lyme disease to people because they are harder to see and a high proportion may be infected.

In San Mateo County, Lyme disease spirochetes have been found in 1-3% of both adult and nymphal western black-legged ticks. However, nymphal ticks are more difficult to collect than adult ticks and have only been evaluated from four sites. The lab will be working to expand collection and testing of nymphs this spring in a greater number of locations.

San Mateo County: Physician Lyme Disease Survey Follow-Up

Entomology Report March 2008, San Mateo County Mosquito Abatement District

Follow-up on the physician survey on Lyme disease continued in March. Based on survey results, the district mailed educational materials to over 200 primary care physicians in San Mateo County. The mailing consisted of a letter about infection in local ticks, instructions on disease reporting, brochures, and tick identification cards.

Results of the survey were presented to the California Lyme Disease Advisory committee in Sacramento on March 12. On March 20, the district discussed the survey in a teleconference of the Communicable Disease Exchange, a forum of health departments from counties throughout California. Two counties in the coastal region have expressed interest in conducting similar surveys or using the results of the present survey to guide physician education.

San Mateo County: Mosquito and Vector Control Association of California Annual Conference (Physician Survey on Lyme Disease)

Entomology Report January 2008, San Mateo County Mosquito Abatement District

Two laboratory staff presented research in the tick-borne disease symposium at the 2007 annual meeting of the Mosquito and Vector Control Association of California. Chindi Peavey, Vector Ecologist, spoke about tularemia, a disease of rabbits and rodents that can sometimes be transmitted to people. There have been 2 cases of tularemia in children in the past 3 years that have been traced to tick exposure on the coast near Pescadero. The District conducted follow-up investigations of these cases with the California department of Public Health in 2004 and 2006.

Assistant Vector Ecologist Lauren Marcus presented the findings of a physician survey performed in San Mateo County, in conjunction with the San Mateo County Health Department. Physicians were asked about their beliefs about Lyme Disease (LD). 86% of respondents believe that LD can be acquired locally. 73% of physicians note that 1 to 5 patients seek medical attention due to a tick bite annually and diagnose an average of 1.4 LD cases in 5 years. Of those who have diagnosed a patient with LD, 40% observed an erythma migrans (EM) rash and 52% stated that the patient had recalled a tick bite within three months of symptom onset. Physicians were asked what types of public education materials would be most useful. A resounding 80% wanted data on tick infection prevalence in the County, followed by 78% who wanted fact sheets on tick ecology, risk exposure, and prevention information. Finally, 73% wanted tick ID cards. Overall, the physician survey was successful in determining beliefs towards LD and what forms of educational materials were desired.

Alameda County: Lyme Disease Surveillance 2006-2007

Annual Report 2006-2007, Alameda County Vector Control Services

As part of the Lyme disease surveillance program, our staff collects and identifies ticks, and recommends testing for tick borne disease when deemed appropriate. Our District provides consultations, educational resources, tick identification, and testing facilities for Lyme disease. Fifteen Ixodes pacificus ticks were submitted to the Sonoma County Public Health Laboratory for Lyme disease testing; all tested negative. The District now has the capability to perform Lyme disease indirect fluorescent antibody (IFA) tests. We hope to expand this capability when new staff is hired.

San Mateo County: Physician Survey on Lyme Disease

Entomology Report June 2007, San Mateo County Mosquito Abatement District

In conjunction with the San Mateo County Public Health Department, laboratory staff have surveyed over 100 physicians throughout the county to assess physician beliefs and awareness about Lyme Disease. So far, 9% of the surveys have been completed and returned. This survey will be used to develop educational materials, geared towards physicians, informing them of the risk of acquiring Lyme Disease in the county.

Previous related entries:

Survey of San Mateo County Physicians on Lyme Disease, March 2007
San Mateo County Physician Survey on Lyme Disease, November/December 2006

San Mateo County: Nymphal Tick Surveillance

Entomology Report May 2007, San Mateo County Mosquito Abatement District

Testing nymphs, the juvenile stage, is an integral part of the Lyme disease surveillance program. Their extremely small, hard to see, size of this stage contributes to their role in transmission of Lyme disease. Nymphs are collected by dragging white flannel sheets over forest floors with dense leaf litter, the preferred habitat of nymphal ticks. Lab and field staff regularly monitor, collect, and test ticks in these areas to determine prevalence of Lyme disease in nymphal ticks. So far, surveys for nymphs have been carried out in Los Trancos Woods, Costanoa Resort in Pescadero, Skyline Ridge Open Space, Edgewood Park in Redwood City and Laurelwood Park in San Mateo.

Previous related entries:

San Mateo County: Tick Flagging with Santa Clara County Vector Control District, April 2007

Los Angeles County West: Locations of Lyme Positive Ticks

Locations of Lyme Positive Ticks, Los Angeles County West Vector Control District

Map:
Sites where ticks positive for Lyme disease bacterium have been found in the district

Charmlee Park
Malibu Creek State Park
Tapia State Park
Topanga State Park
Will Rogers State Park
Palos Verdes Estates - Bluff Cove
Rolling Hills - Purple Canyon Trail

Lyme Disease in Santa Clara County: Tick Infection Rates

Source: Lyme Disease in Santa Clara County, Santa Clara County Vector Control District

Location of tick sampling    % positive to Borrelia burgdorferi
Freemont Older                     3.85
Foothills Open Space Dist.         2.86
Sierra Azul                        2.86
Sanborn Skyline                    2.78
Alum Rock Park                     2.75
Uvas County Park                   2.39
Duveneck Windmill OSD              2.27
Villa Montalvo                     2.22
Almaden Quicksilver                1.72
Los Trancos                        1.26

San Mateo County: Tick Flagging with Santa Clara County Vector Control District

Entomology Report April 2007, San Mateo County Mosquito Abatement District

In April, District staff focused on collection of nymphal ticks for Lyme disease testing. On April 18, District laboratory staff collaborated with Santa Clara County Vector Control to search for nymphal ticks in sites near the county border. Sampling was carried out on Old Spanish Trail in Los Trancos Woods and at Foothill Park in Los Altos. These ticks are in the process of being tested for Lyme disease. Ixodes pacificus nymphs are active during the spring and early summer and are easily overlooked due to their small size. Nymphs infected with the bacteria that causes Lyme disease have been found throughout San Mateo County.

San Mateo County: Public Education and Other Activities: Lyme Disease and Ticks

Entomology Report March 2007, San Mateo County Mosquito Abatement District

• Dr. Chindi Peavey, the District Vector Ecologist, gave a presentation on Lyme Disease Ecology and Surveillance at El Camino Hospital on March 17 in conjunction with Dr. Anne Kjemtrup, from the California Department of Health Services, and Victor Romano, from Santa Clara County Vector Control.
• Laboratory staff distributed a press release on the presence of vector ticks in vacant lots in a well-developed residential area in Pacifica. This story was picked up and published in an article by the Pacifica Tribune. The article has generated a number of calls from residents on the coast. Laboratory staff visited additional sites and spoke with residents about ways to reduce the risk of acquiring Lyme Disease.
• Legislation declaring May as Lyme Disease Awareness Month is currently going through the state legislature.

Survey of San Mateo County Physicians on Lyme Disease

Entomology Report March 2007, San Mateo County Mosquito Abatement District

A pilot survey was performed to determine attitudes and beliefs of physicians in San Mateo County on the acquisition of Lyme Disease in the county, treatment options, and the possibilities of co-infections. Training was provided by the San Mateo County Public Health Department on survey completion and the pilot was performed with local infectious disease doctors. The questionnaire is now in the process of redesign to accommodate the needs of doctors for the full survey.

Previous related entries:

San Mateo County Physician Survey on Lyme Disease, November/December 2006

A 6-Year Analysis of Tick Surveillance in San Mateo County

Entomology Report February 2007, San Mateo County Mosquito Abatement District

% Infection of I. pacificus in San Mateo County Parks
Location             # Ix. pacificus Tested  % Infection
Pulgas Ridge                    60                3.3
Los Trancos Woods              733                2.5
Huddart Park                   140                2.1
Big Canyon Park                507                1.8
Crystal Springs Trail          556                1.6
San Pedro Valley Park          333                0.9
Laurelwood Park                428                0.7
Edgewood Park                  195                0.5

An analysis of tick surveillance data from 2002 through February 2007 in San Mateo County was performed. Adult Ixodes pacificus ticks have been collected from 11 parks. Thus far Lyme disease spirochetes have been detected in ticks from 8 parks (Big Canyon Park, Crystal Springs Trail, Edgewood Park, Huddart Park, Laurelwood Park, Los Trancos Woods, Pulgas Ridge, and San Pedro Valley Park). The prevalence of infection in ticks at these parks ranged from 0.5% - 3.3%. Ticks collected from Costanoa, Sweeney Ridge, and Water Dog Lake have not yet tested positive for Lyme Disease spirochetes.

Previous related entries:

Tick Surveillance in San Mateo County, January 2007, January 2007
Tick Surveillance in San Mateo County, December 2006, December 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, June 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, April 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, March 2006
San Mateo County: Lyme Disease Surveillance 2006, February 2006
San Mateo County: Lyme Disease Surveillance 2006, January 2006
San Mateo County: Lyme Disease Surveillance, November/December 2005
San Mateo County: Lyme Disease Surveillance, October 2005
San Mateo County: Lyme Disease Surveillance, January 2005

Tick Surveillance in San Mateo County, January 2007

Entomology Report January 2007, San Mateo County Mosquito Abatement District

In January, tick collections were made from Edgewood Park, (Redwood City), Huddart Park, (Woodside), Laurelwood Park (San Mateo), Water Dog Lake (Belmont), and Costanoa (Pescadero). So far, a total of 827 ticks from 5 parks were collected. Evidence of infection with Lyme disease spirochetes was detected for the first time in Edgewood Park (1 positive) and Laurelwood Park (3 positives).

The District was contacted from residents of Belmont (near Water Dog Lake) and Pacifica with concerns about ticks in their neighborhoods. In Pacifica, questing ticks can be found in the open spaces between homes. In Belmont, western black-legged ticks were found inside a home adjoining the open space around Water Dog Lake, presumably brought in by the family cat. These instances illustrate the need to watch out for ticks even if one does not engage in outdoor activities at this time of year.

Previous related entries:

Tick Surveillance in San Mateo County, December 2006, December 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, June 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, April 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, March 2006
San Mateo County: Lyme Disease Surveillance 2006, February 2006
San Mateo County: Lyme Disease Surveillance 2006, January 2006
San Mateo County: Lyme Disease Surveillance, November/December 2005
San Mateo County: Lyme Disease Surveillance, October 2005
San Mateo County: Lyme Disease Surveillance, January 2005

San Mateo County: Results of the Evaluation of Trailside Mowing as a Tick Control Method

Entomology Report January 2007, San Mateo County Mosquito Abatement District

This four-week study concluded that the mowing of grass on the sides of public recreation trails in San Mateo County was not an effective control method for Dermacentor ticks. In fact, although the sample size was relatively small, the density of Dermacentor variabilis ticks was found to have increased slightly on sites after they had been mowed. The density of Dermacentor occidentalis was not shown to have any significant relationship to mowing. While they do not transmit Lyme Disease, Dermacentor ticks remain a public health concern, as they are known to vector both Rocky Mountain Spotted Fever and Tularemia, and are very common ticks in San Mateo County.

Previous related entries:

San Mateo County: Effects of Mowing on Summer Tick Populations, June 2006

San Mateo County: Results of the Efficacy of Suspend on Density of Ticks Along a Recreational Trail, January 2007
San Mateo County: Trial Application of Suspend for Control of Ticks, May 2006
San Mateo County: Trial Application of Suspend for Control of Ticks, April 2006

Ticks and Lyme Disease in Contra Costa County 2006

2006 Annual Report, Contra Costa County Mosquito and Vector Control District

Lyme disease is a bacterial infection transmitted by the Western black-legged tick (Ixodes pacificus), also known as the deer tick. While Lyme disease is rare in Contra Costa County (on average there are two to four human cases reported per year), it can cause serious complications if not treated promptly. The District monitors the risk of Lyme disease by collecting and testing black-legged ticks from several locations that we have been monitoring for as long as 12 years. These include Bollinger Canyon Rd., San Ramon; Springhill Rd., Lafayette; and the Bear Creek area of Briones Regional Park. The adult Western black-legged tick population was below average for most of the season, except during the last half of March where counts slightly exceeded the average. An unusually high number of days with rainfall during the collecting season limited the number of possible collection days; thus reducing the numbers of ticks collected. The graph below shows the average number of ticks that were collected from these locations.

On average, only one or two in a hundred black-legged ticks test positive for Lyme disease, although we have found a few locations where the rate is higher, and these tend to change over time. In 2006, we collected and tested 132 ticks from three locations; the highest infection rate was in the Bollinger Canyon area in San Ramon where three out of 58 ticks tested positive (just over 5 percent).

We also identify and test ticks brought in by members of the public who have been bitten. If the ticks are reasonably intact and not dried out, we can test them in our own laboratory free of charge. If they are in poor condition or dead, a more sensitive test is required and county residents have the option of allowing us to send the tick to a private laboratory for a fee of $60 (our cost). Out of 54 ticks tested for residents in 2006, only one was positive for Lyme bacteria (just below 2 percent).

Tick Surveillance in San Mateo County, December 2006

Entomology Report November/December 2006, San Mateo County Mosquito Abatement District

The Western black-legged tick, the vector of Lyme disease, becomes active with the commencement of winter rains. These ticks require cool, moist conditions to survive and are commonly encountered along recreational trails during winter. Last year, 22 trails in 8 parks were surveyed by District staff and other agencies. This year, the District will again coordinate with the San Mateo County Department of Public Health and the Land and Resources Division of the San Francisco Public Utilities Commission in surveying additional parks within the county. So far this season, 669 ticks have been collected and are in the process of being tested for Lyme disease.

Park             Total # Females  Total # Males  Adult Density
                 Collected        Collected      ticks/100 ft
Edgewood Park                 51             70            0.9
Huddart Park                   8              9            0.2
Laurelwood Park              130            129           12.5
Water Dog Lake                50             97            2.0
Costanoa                      62             63            5.2
Grand Total (12/8/06-1/3/07) 301            368

Previous related entries:

San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, June 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, April 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, March 2006
San Mateo County: Lyme Disease Surveillance 2006, February 2006
San Mateo County: Lyme Disease Surveillance 2006, January 2006
San Mateo County: Lyme Disease Surveillance, November/December 2005
San Mateo County: Lyme Disease Surveillance, October 2005
San Mateo County: Lyme Disease Surveillance, January 2005

San Mateo County: Physician Survey on Lyme Disease

Entomology Report November/December 2006, San Mateo County Mosquito Abatement District

The District is working with epidemiologists from the Health Department of San Mateo County this winter to determine the level of awareness among local physicians about Lyme Disease. A survey will be administered to local infectious disease physicians. The survey will be based on one developed by California Dept. of Health Services in 2004. The former survey was administered statewide, but the response rate in many counties was very low (only 2 physicians replied in San Mateo County). By conducting the survey at a local level and contacting physicians by telephone, it is hoped that we can increase the response rate. This information will help to assess the level of awareness among local doctors about the existence of Lyme disease among ticks here in San Mateo County.

Tick Surveillance in California, 2005

Vector-Borne Diseases in California, Annual Report 2005, California Department of Health Services, Vector-Borne Disease Section

Tick surveillance

CDHS Vector-Borne Disease Section (VBDS) and collaborating agencies conducted tick surveillance in 17 California counties in 2005. Totals of 1,965 Ixodes pacificus (1,797 adults and 168 nymphs), 782 Dermacentor occidentalis, and 38 Dermacentor variabilis were collected. Nineteen hundred I. pacificus (1,736 adults and 164 nymphs) from 16 counties were tested for Borrelia burgdorferi in two laboratories. Ticks were tested by indirect fluorescent antibody (IFA) and/or polymerase chain reaction (PCR). Evidence of Borrelia sp. was identified in ticks collected from six counties. Borrelia burgdorferi was detected in 4 of 33 pools by IFA and 12 of 192 pools by PCR.

The U.S. Army Center for Health Promotion and Preventive Medicine tested by PCR 1,618 I. pacificus. Any ticks initially positive for the genus Borrelia were tested by an additional PCR assay using primers specific to B. burgdorferi. Borrelia sp. spirochetes detected in tick pools from Placer (1), Shasta (1), Trinity (1), Tuolumne (1) Counties did not match the genetic sequence for B. burgdorferi. These isolates most closely resembled B. miyamotoi, a Borrelia species in the RF genetic complex. Borrelia miyamotoi is not known to be pathogenic to humans.

A study of the ecology of I. pacificus in southern California, initiated in 2001, continued in 2005. VBDS and collaborating agencies (Los Angeles County Department of Health Services, Los Angeles West Vector Control District, and Riverside County Department of Health) monitored tick populations and collected questing ticks from six sites at three different geographic locales (Griffith Park, Santa Monica Mountains, and San Jacinto Mountains). Meterological factors, including rainfall and humidity, were simultaneously monitored. These data on tick populations, meterological factors, infections with B. burgdorferi, and molecular characterization of Borrelia spp. from ticks will continue to be collected to gain a better understanding of the ecology of I. pacificus ticks and B. burgdorferi in southern California.

Local surveillance was conducted in San Mateo County for Rickettsia rickettsii, the agent of Rocky Mountain spotted fever. In June, CDHS and San Mateo County Mosquito Abatement District personnel collected 320 D. occidentalis and 27 D. variabilis. All ticks were tested by PCR for R. rickettsii by CDHS, Viral and Rickettsial Disease Laboratory; all tested negative. In addition, 120 Rhipicephalus sanguineus were collected from Riverside County. Of 62 ticks tested by PCR at the Division of Viral and Rickettsial Diseases, CDC, R. rickettsii was detected in one adult male R. sanguineus.

In June, CDHS collected 362 D. occidentalis and 5 D. variabilis in Tilden Regional Park, located in Contra Costa and Alameda Counties, as part of a continuing investigation of two human cases of tularemia in 2004. Ticks were tested for Francisella tularensis in 39 pools by PCR at DVBID CDC; all pools tested negative.

Tick-Borne Disease Surveillance in California, 2005

Vector-Borne Diseases in California, Annual Report 2005, California Department of Health Services, Vector-Borne Disease Section

Human disease surveillance

Lyme disease

A total of 94 cases of Lyme disease were reported to the California Department of Health Services (CDHS) in 2005. Case-patients were residents of 26 counties. Humboldt County reported the most cases (11). Reported incidence was highest in Trinity County at 23 cases per 100,000 residents. Of 44 cases for whom county of likely exposure was reported, 32 had exposure outside their county of residence; 28 of these reported exposure outside California. The most frequently reported location of exposure was Massachusetts (eight cases).

The median age of reported Lyme disease cases was 43 years (range, 3 to 78 years) and 51 (54%) were female. Of 79 cases for which race was reported, 74 (94%) were white, 3 were Native American, and 1 each was Asian and Black. Erythema migrans (EM) was identified in 59 (63%) cases. Of 51 cases with EM for which date of illness onset was reported, 36 (71%) occurred between May and August.

Tick-borne relapsing fever

Five cases of tick-borne relapsing fever (RF) were reported to CDHS in 2005. Case-patients were residents of three counties (El Dorado, Humboldt, Santa Cruz) and ranged from 6 to 58 years old. Four case-patients were likely infected in the greater Lake Tahoe area; one case-patient was likely infected while visiting a private cabin in Lassen County. One case had onset of illness in April, while the remaining four had onset in late July and August.

CDHS collaborated with the El Dorado County Departments of Health and Environmental Management, the Nevada State Health Division, and the Division of Vector-Borne Infectious Diseases (DVBID), U.S. Centers for Disease Control and Prevention (CDC), to investigate two cases of RF with unusually severe clinical courses. A 46-year-old woman from Nevada and a 43-year-old woman from El Dorado County both developed RF between February and April that progressed to severe respiratory distress and extended hospitalizations. Both patients eventually recovered. Both case-patients had a history of travel to or residence in the Lake Tahoe area. Preliminary investigation of the California case’s residence revealed live and dead mice in the garage, as well as live chipmunks in and around the house. One engorged Ornithodoros sp. tick was discovered in the bedroom. Several Ornithodoros ticks were also recovered from rodent and bird nests removed from underneath the building’s exterior siding.

Reported Lyme Disease Cases by County of Residence, California, 1996-2005

Vector-Borne Diseases in California, Annual Report 2005, California Department of Health Services, Vector-Borne Disease Section

Reported Lyme disease cases by county of residence,
California, 1996-2005.
                                                      Incidence/
                                                      100,000
County        '96 '97 '98 '99 '00 '01 '02 '03 '04 '05 person-yrs
Alameda         2   3   6   3   4   3   5   1   0   5   0.22
Alpine          0   0   0   0   0   0   0   0   0   0   0.00
Amador          0   0   0   1   0   1   0   0   0   0   0.57
Butte           4  53  13  18   3   1   3   2   2   0   4.84
Calaveras       0   0   0   0   1   0   0   0   0   0   0.25
Colusa          0   0   0   0   0   0   0   0   0   0   0.00
Contra Costa    1   6   2   1   1   5   3   4   0   4   0.28
Del Norte       0   1   0   1   0   0   2   0   0   0   1.44
El Dorado       0   3   2   1   0   0   0   0   3   3   0.75
Fresno          1   0   0   0   1   0   0   0   0   0   0.02
Glenn           0   2   0   1   1   0   0   0   0   0   1.50
Humboldt        5  19  20  14  10   4   4   5   7  11   7.80
Imperial        0   1   0   0   0   0   0   0   0   0   0.07
Inyo            0   0   0   0   0   1   0   0   0   0   0.55
Kern            1   2   2   2   2   0   2   1   0   2   0.21
Kings           0   0   0   0   0   0   0   0   0   0   0.00
Lake            0   1   2   1   0   1   0   1   1   1   1.36
Lassen          0   2   1   2   0   0   2   0   0   0   2.04
Los Angeles     2   6   3   7   2   9   6   7   2   9   0.05
Madera          0   0   0   1   0   0   0   0   0   0   0.08
Marin           0   4   8   4   3   1   4   4   0   1   1.25
Mariposa        0   0   0   0   0   0   1   0   1   0   1.17
Mendocino       3   2  16   8   7   4  11   6   2   0   6.90
Merced          0   2   0   1   1   0   0   0   0   0   0.19
Modoc           0   0   0   0   0   0   0   0   0   0   0.00
Mono            1   0   0   1   0   0   0   3   1   0   4.67
Monterey        0   2   1   2   1   0   5   1   1   0   0.32
Napa            1   3   0   2   2   3   3   0   1   1   1.28
Nevada          2   1   4   5   9   6   3   4   1   3   4.12
Orange          0   0   1   2   3   0   3   2   0   1   0.04
Placer          0   5   4   2   1   4   3   0   2   2   0.92
Plumas          3   0   2   1   0   1   0   0   0   0   3.37
Riverside       1   0   0   0   3   2   1   2   1   4   0.09
Sacramento      0   5   1   1   3   4   1   4   2   6   0.22
San Benito      0   0   0   0   0   1   1   0   0   0   0.37
San Bernardino  0   0   0   1   1   0   0   2   0   0   0.02
San Diego       5   4   0  16   9   3   7   2   4   8   0.20
San Francisco   4   1   7   1   2   3   3   3   1   7   0.42
San Joaquin     1   2   0   0   0   0   0   0   0   0   0.05
San Luis Obispo 1   0   1   1   1   0   0   0   0   1   0.20
San Mateo       2   3   4   4   2   4   4   5   1   4   0.46
Santa Barbara   1   1   3   0   0   1   2   2   2   0   0.30
Santa Clara     2   4   6   2   2   2   6   4   0   2   0.18
Santa Cruz      2   2   2   2   5   9   1   8   3   0   1.32
Shasta          1   0   2   0   0   2   1   0   2   2   0.61
Sierra          0   0   0   0   0   0   0   0   0   0   0.00
Siskiyou        0   1   1   0   0   1   1   0   0   0   0.89
Solano          0   0   0   0   1   1   0   0   0   0   0.05
Sonoma         13  10  15  14   8   6   4   9   2   9   1.95
Stanislaus      3   1   0   0   1   1   0   0   0   1   0.16
Sutter          0   1   0   0   1   1   0   0   0   0   0.38
Tehama          0   1   1   0   2   0   0   0   0   0   0.72
Trinity         1   0   1  13   1   1   1   1   3   3  19.23
Tulare          1   0   1   1   0   2   0   2   0   0   0.19
Tuolumne        1   0   0   0   0   2   1   0   0   1   0.91
Vetura          0   0   2   1   2   2   1   1   2   1   0.16
Yolo            0   0   0   0   0   0   2   0   1   0   0.18
Yuba            0   0   1   1   0   0   0   0   0   0   0.33
Total          65 154 135 139  96  92  97  86  48  94   0.30