Epidemiological landscape in a Mediterranean hotspot of human leishmaniosis in Spain under a One Health approach

Integrated One Health studies are essential to assess the potential risks associated with leishmaniosis hotspots in Europe. Thus, the aim was to holistically evaluate <i>Leishmania infantum</i> epidemiology in a rural hotspot in Spain with a high incidence of human leishmaniosis. Samples from 145 humans (blood), 41 dogs (blood and hairs), and 41 wild lagomorphs (blood, skin, and spleen) were collected during 2022–2023. Sandflies were captured with CDC-traps, and blood-feeding was evaluated. <i>L. infantum</i> exposure was assessed using indirect immunofluorescence and/or quantitative PCR. Positivity was detected in 6.2% of humans, 73.2% of dogs, and 100% of lagomorphs. A total of 1,347 sandflies were captured, predominantly <i>Phlebotomus perniciosus</i>. Blood meal analysis identified several synanthropic animals, as well as humans, as blood-sources. <i>L. infantum</i> DNA was detected in 65.7% of pooled and 25.8% of individual sandfly specimens. A spatial cluster of <i>L. infantum</i> positivity was identified near a hunting area harboring lagomorphs. Phylogeny revealed high homology between <i>L. infantum</i> isolates from lagomorphs and sandflies. Our results reinforce the role of wild lagomorphs as pivotal <i>L. infantum</i> reservoirs, favoring the occurrence of human leishmaniosis at the wildlife-human-domestic interface. This study underscores the need to integrate One Health approaches in endemic areas of leishmaniosis to establish effective prevention and control measures.