Sampling implications of variation in daily activity of the sheep tick, Ixodes ricinus at a coastal grassland site in the U.K.

ABSTRACT

The sheep tick, Ixodes ricinus L. (Acari Ixodidae), is an important vector of many pathogens of medical and veterinary significance. Determining vector abundance is a requisite of assessing potential vector-borne disease risk. Estimation of tick abundance is often conducted by blanket drag sampling a site, conducted at one time point during the day. The time of day chosen for sampling can vary, is not widely standardized and is often unreported by the investigator. This study investigated whether the time of day chosen for sampling had an effect on tick collection at an open grassland coastal site in North Devon, U.K., during May 2019 to July 2019. Tick abundance for both adults and nymphs in the evening period was more than twice that found in the mid-day sampling period. Overall abundance differed with site aspect, ground temperature and relative humidity. This study shows that for this open grassland recreational site, the time of day chosen for sampling has important implications for tick collection and the assessment of the relative risk of human exposure to ticks and tick-borne infections.