Tick Surveillance Update for April 2018
Searching for Nymphal Ticks

The nymph stage is the second of three stages in a tick’s life cycle.  It is thought that nymphs are the most dangerous stage of ticks because they are more likely to be carrying bacteria that causes a tick-borne disease such as Lyme, and because they are significantly smaller and harder to see than adult ticks.  Tick nymphs are most active in the spring months in California and can be found on tree stumps, downed logs, rocks, and in leaf litter.

Lab staff are making an extra effort this year to collect nymphs from a select number of parks and open spaces in San Mateo County that have abundant nymphal habitat.  So far, nymph collections have been made at Los Trancos Open Space Preserve, Skyline Ridge Open Space Preserve, and Crystal Springs Regional Trail.

Lab staff will be testing all collected nymphs for the presence of disease causing bacteria and comparing results to adult ticks collected earlier in the year.  Estimating disease prevalence in nymphal ticks may present a more complete risk assessment because of their role in disease transmission.