Contents lists available at ScienceDirect Ticks and Tick-borne Diseases journal homepage: www.elsevier.com/locate/ttbdis Surveillance of British ticks: An overview of species records, host associations, and new records of Ixodes ricinus distribution Benjamin Cull a, ⁎ , Maaike E. Pietzsch a , Kayleigh M. Hansford a , Emma L. Gillingham a , Jolyon M. Medlock a,b,c a Medical Entomology & Zoonoses Ecology, Emergency Response Department Science & Technology, Public Health England, Porton Down, SP4 0JG, United Kingdom b Health Protection Research Unit in Environment and Health, Porton Down, Salisbury, UK c Health Protection Research Unit in Emerging and Zoonotic Infections, Porton Down, Salisbury, UK ARTICLE INFO Keywords: Surveillance Ixodes ricinus Distribution Tick United Kingdom Endemic Imported ABSTRACT Public Health England’s passive Tick Surveillance Scheme (TSS) records the distribution, seasonality and host associations of ticks submitted from across the United Kingdom (UK), and helps to inform the UK government on emerging tick-borne disease risks. Here we summarise data collected through surveillance during 2010–2016, and compare with previous TSS data from 2005 to 2009, particularly in relation to the primary Lyme borreliosis vector Ixodes ricinus. 4173 records were submitted, constituting > 14,000 ticks; 97% were endemic tick records (13,833 ticks of 11 species), with an additional 97 records of imported ticks (438 ticks of 17 species). Tick submissions were mainly from veterinary professionals (n = 1954; 46.8%) and members of the public and amateur entomologists (n = 1600; 38.3%), as well as from academic institutions (n = 249; 6.0%), wildlife groups (n = 239; 5.7%) and health professionals (n = 131; 3.1%). The most commonly reported hosts of en- demic ticks were dogs (n = 1593; 39.1% of all records), humans (n = 835; 20.5%) and cats (n = 569; 14%). New host associations were recorded for a number of tick species. Ixodes ricinus was the most frequently recorded endemic tick species (n = 2413; 59.2% of all records), followed by I. hexagonus (n = 1355; 33.2%), I. canisuga (n = 132; 3.2%) and I. frontalis (n = 56; 1.4%), with other species each making up < 1% total records. 81% of I. ricinus recorded from humans were nymphs, whereas 93.4% of I. ricinus from companion animals were adults. Recent TSS records of I. ricinus in the UK add a considerable amount of new presence data for this species, particularly in the southern regions of England, and confirm that this species is widespread across the UK. The scheme remains a valuable method of collecting continuous national distribution data on ticks from a variety of host species. 1. Introduction Ticks are haematophagous arthropods that parasitise a wide range of vertebrate hosts, and a number of tick species are of medical and veterinary importance due to their role as disease vectors. Therefore, up-to-date knowledge of the distribution, seasonal activity and host associations of potential vector tick species is required not only to un- derstand the role they may play in the maintenance and transmission of pathogens, but also to assess the risk of tick-borne diseases in a given region (Medlock and Jameson, 2010). In Europe, the most widely dis- tributed tick species is Ixodes ricinus, which is a vector of multiple human and animal pathogens, including Borrelia burgdorferi sensu lato (s.l.), tick-borne encephalitis virus, Anaplasma phagocytophilum, and Babesia spp. Studies from Europe suggest that the distribution of I. ri- cinus may be expanding and that its abundance may be increasing (Jaenson et al., 2012; Jore et al., 2014; Korotkov et al., 2015; Medlock et al., 2013; Scharlemann et al., 2008). Such changes may be associated with increasing incidence of tick-borne disease (Heyman et al., 2010; Randolph, 2001; Sumilo et al., 2007). Expansion of I. ricinus distribu- tion has been linked to changes in climate, host distribution and land- use (Jore et al., 2014; Korotkov et al., 2015; Medlock et al., 2013), although in many countries changes in tick distribution and abundance have been difficult to ascertain due to a lack of baseline data from historical tick surveillance with which to compare recent data. Collecting uniformly-recorded distribution data at a national scale can be difficult, as the detailed surveying methods commonly applied to targeted studies, i.e. active collection of ticks from the environment (e.g. Hansford et al., 2015) or host animals (e.g. Cull et al., 2017), are not resource-efficient at a large scale. Therefore, attempting to under- stand the national distribution of ticks is often achieved by combining https://doi.org/10.1016/j.ttbdis.2018.01.011 Received 8 November 2017; Received in revised form 15 January 2018; Accepted 22 January 2018 ⁎ Corresponding author. E-mail address: ben.cull@phe.gov.uk (B. Cull). Ticks and Tick-borne Diseases xxx (xxxx) xxx–xxx 1877-959X/ Crown Copyright © 2018 Published by Elsevier GmbH. All rights reserved. Please cite this article as: Cull, B., Ticks and Tick-borne Diseases (2018), https://doi.org/10.1016/j.ttbdis.2018.01.011