The Channel Islands are British Crown dependencies located in the English Channel to the west of the Normandy coast in northern France. Whilst there have been studies investigating tick occurrence and distribution in different habitats on the mainland of the UK and in France, the Channel Islands have been relatively understudied. As such, little is known about whether the sheep tick, Ixodes ricinus, is present, and whether there is a potential risk of Lyme borreliosis on the Channel Islands. To ascertain the presence of I. ricinus on the three largest islands in the archipelago: Jersey, Guernsey and Alderney, surveys of ticks questing in the vegetation and ticks feeding on hosts were undertaken during April and May 2016. Across all three islands, the highest numbers of ticks were found in woodland habitats. Ixodes ricinus was the predominant questing tick species found on Jersey, and Ixodes ventalloi the most common questing tick species on Alderney and Guernsey, with little or no evidence of questing I. ricinus on either island. During field studies on small mammals, I. ricinus was the predominant tick species feeding on Jersey bank voles (Myodes glareolus caesarius), with Ixodes hexagonus the most common species infesting hedgehogs on Guernsey. We propose that the greater diversity of small mammals on Jersey may be important in supporting immature stages of I. ricinus, in contrast to Guernsey and Alderney. Morphological identification of tick species was confirmed by PCR sequencing based on amplification of the cytochrome c oxidase subunit one (cox1) gene (COI DNA barcoding). To date, there have been few records of human tick bites in the Channel Islands, suggesting that the current risk from tick-borne disease may be low, but continued reporting of any human tick bites, along with reporting of cases of Lyme borreliosis will be important for continued assessment of the impact of tick-borne diseases in the Channel Islands.

Alderney Wildlife Trust 51 Victoria Street St Anne Alderney GY93TA Guernsey

Biodiversity Institute of Ontario University of Guelph Ontario N1G 2W1 Canada

Charles University Opletalova 38 110 00 Staré Město Czechia

Environment Guernsey Ltd The Old Tobacco Factory Route De La Ramee St Peter Port GY1 2ET Guernsey

Howard Davis Farm la Route de la Trinité Trinity JE3 5JP Jersey

Jersey General Hospital The Parade St Helier JE1 3QS Jersey

Medical Entomology and Zoonoses Ecology Emergency Response Department Public Health England Porton Down Salisbury SP4 0JG UK

NIHR Health Protection Research Unit in Emerging and Zoonotic Infections UK

NIHR Health Protection Research Unit in Environmental Change and Health UK

Wildlife Zoonoses and Vector Borne Research Group Department of Virology Animal and Plant Health Agency Addlestone Surrey KT15 3NB UK

References provided by Crossref.org