Abstract
Canine babesiosis is a parasitic disease caused by apicomplexan protozoa of the genus Babesia, with Babesia canis being a pathogenic and widespread species in mainland Europe. The United Kingdom has thought to have been free of endemic B. canis infection, despite its vector, Dermacentor reticulatus being present in endemic foci. The winter of 2015/2016 saw the establishment of the first recording of a known endemic foci of B. canis in the UK. Since this outbreak in Harlow and subsequent cases in Romford later in 2016, information has been gathered regarding the population of Dermacentor ticks in Harlow and awareness of the disease promoted among Veterinary professionals and pet owners. This letter describes what is known about the two clusters of cases seen in 2016 and the distribution of D. reticulatus in the UK. A further untraveled case in the UK in 2017 close proximity to the 2016 cases is also described, as well as the lessons this outbreak brings in terms of managing other vector-borne disease.