San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06

Entomology Report April 2006, San Mateo County Mosquito Abatement District

The season for adult western black-legged ticks (vector of Lyme disease) is coming to a close. A total of 1,065 ticks were collected in 2005-06. This is twice the number collected in previous years. Participation by staff from the San Mateo County Health Department, the San Francisco Water Department and the California State Parks Department greatly increased the number of sites surveyed. Most collections were made in January and February. Frequent rains limited the number of days in March that surveys could be conducted. Ixodes pacificus ticks do not quest actively during heavy rains.

Park                              # Infected
Big Canyon, San Carlos            5/219  (2%)
Crystal Springs Trail, Millbrae   3/108  (3%)
Edgewood Pk, Redwood City         0/ 41  (0%)
Huddart Pk, Woodside              2/ 21 (10%)
San Pedro Valley Pk, Pacifica     3/252  (1%)

Previous related entries:

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: Trial Application of Suspend for Control of Ticks

Entomology Report April 2006, San Mateo County Mosquito Abatement District

In May, the District conducted a small trial on the effectiveness of Suspend for control of ticks along recreational trails. The material was applied in a 8 ft swath along the uphill side of a 0.37 mi stretch of trail. 90 ticks were collected before treatment. Sampling was conducted three days and one week after treatment. 1 male tick was collected after three days and 0 ticks were collected at one week. In contrast, a segment of the trail immediately adjacent to the treated area contained 131 ticks per 0.27 mi. This data suggests that the control work was effective. The District will determine the feasibility of different control methods and make it available to the public. Assistance will be given to other agencies seeking methods to control ticks in high risk areas.

Reported Cases of Lyme Disease in Sonoma County

Lyme Disease Cases Up in County, Marin / Sonoma Mosquito and Vector Control District

Fifteen cases were reported through April, according to county health officials, who said May and June tend to be the months in which the tick-borne disease is worst.

There were 16 cases all of last year in Sonoma County.

Lyme Disease Cases:
2003       Sonoma County - 11
2004       Sonoma County -  4
2005       Sonoma County - 16
2006*      Sonoma County - 15
*As of April 30, 2006