GD01 The hidden endemicity of cutaneous leishmaniasis in Europe and its implications for UK dermatologists

Abstract

Cutaneous leishmaniasis (CL) is a neglected vector-borne parasitic disease transmitted by the Phlebotomus sandfly. Globally, 1 million new cases are reported each year, primarily in the Americas, the Middle East, Central Asia and the Mediterranean basin. Recent WHO data (2024) reveal that CL is now endemic in 25 of 53 European countries, including most of Southern Europe, challenging the conventional epidemiological narrative on the continent. We conducted a narrative synthesis of WHO Global Health Observatory data, epidemiological studies from Europe, vector distribution models, and clinical case series to investigate factors driving the hidden endemicity of CL in Europe (the discordance between established endemicity at the population level without proportionate clinical case detection). Multiple interacting factors contribute to the hidden endemicity of CL in Europe. Climate-driven expansion of the sandfly vector in Europe, facilitated by rising temperatures and atmospheric moisture, has extended its distribution northwards as far as 50 °N. There is up to a 20% seroprevalence of Leishmania infantum infection in dogs, an important zoonotic reservoir, in Southern Europe. Systematic reviews demonstrate a human leishmaniasis prevalence of 11% in endemic European areas, with 65% of infections being asymptomatic; however, human CL notification remains disproportionately low. Under-reporting, diagnostic delay and highly focal heterogeneous parasite transmission create ‘vectors without disease’ zones that may reflect surveillance limitations rather than true absence of autochthonous transmission in Europe. Although the UK remains nonendemic, increasing travel to southern Europe, importation of infected dogs, growing immunosuppressed travelling populations, and climate change create potential exposure pathways for leishmaniasis. A transdisciplinary One Health approach integrating human, animal and vector surveillance with improved clinical awareness is critical to address this emerging global health challenge. Dermatologists must maintain clinical vigilance for CL in patients with compatible lesions and relevant exposure history.