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.