Tick-Borne Diseases in Santa Cruz County 2005

Annual Report 2005, Santa Cruz County Mosquito and Vector Control District

The County had six reported cases of Lyme disease, and one reported case of relapsing fever in 2005 from tick bites. Lyme disease continues to be the most important vector-borne disease in the State, with 94 reported cases in 2005. As part of an effort to enhance services, MVC now accepts, identifies, and submits ticks for Lyme disease testing for persons who have been bitten. Prevention of bites and recognition of symptoms by the public and physicians are the most recommended methods of dealing with tick-borne disease. There is currently no efficient means to control ticks other than clearing brush.

Reported Cases of Tularemia in California 2004

Annual Report 2005, Alameda County Vector Control Services

Tularemia, a diseased caused by strains of Francisella tularensis, is not commonly transmitted by contacting rodents or tick bites. However, three human cases of tularemia were reported to CDHS in 2004; two of which were likely acquired through a tick bite: one from Alameda County and one from Contra Costa County. The adult American dog tick (Dermacentor variabilis) removed from the Alameda case was tested positive by culture and PCR for F. tularensis (type B) by Center for Disease Control and Prevention (CDC). Because of the human cases and also its importance as a bioterrorism agent, the CDHS requested blood samples from various animals for testing. Blood samples from twenty-three rodents from various locations in Alameda County were submitted for testing. None of these samples showed infection with F. tularensis. United State Department of Agriculture (USDA) – Animal and Plant Health Inspection Service (APHIS) submitted additional twenty-eight blood samples of feral cats, skunks, Norway rats, jackrabbits and red foxes. Of these, one striped skunk tested positive for the tularemia pathogen.

San Mateo County: Lyme Disease Surveillance

Entomology Report November/December 2005, San Mateo County Mosquito Abatement District

Surveillance for the western black-legged tick, Ixodes pacificus, has commenced for the 2005-2006 season. Adults of this species are abundant along recreational trails from November through May. Surveillance is being conducted with the assistance of a number of other agencies to determine the risk of Lyme disease exposure in San Mateo County. Ticks are collected on trails commonly used by the public. They are dissected and tested in the District laboratory to determine the prevalence of infection with the Lyme disease bacteria, Borrelia burgdorferi. Agencies participating in this project include: 3 divisions of the San Mateo County Department of Public Health (Environmental Health, Communicable Disease Control, and the Public Health Laboratory), County Parks, and State Parks. Staff from the San Francisco Department of Public Utilities (the Water Department) are also assisting in collecting on Crystal Springs Watershed.

So far this season, collections have been made at 6 parks. Tick density was low on the trails sampled early in the season (November). Surveillance in December yielded a larger number of ticks, with the highest density in Big Canyon Park. The first positive ticks of the season were collected from the San Andreas Trail. This site has yielded positive ticks in the past. Parks with low tick density will be sampled again later in the season. Other parks that may be surveyed this season, include Mills Canyon Park in Burlingame, Spur Trail Park in Millbrae, Edgewood Park in Redwood City, Smith Field Park in Half Moon Bay, and Sawyer Camp Trail in San Mateo.

Previous related entries:

San Mateo County: Lyme Disease Surveillance, October 2005
San Mateo County: Lyme Disease Surveillance, January 2005