Seroepidemiological Surveillance of Livestock Within an Endemic Focus of Leishmaniasis Caused by Leishmania infantum

Leishmaniasis by <i>Leishmania infantum</i> has a zoonotic transmission cycle involving an increasing number of mammalian hosts, forming a cooperative network. The sand fly feeding on livestock is evidenced, but clinical confirmation regarding their infection is limited. We aimed to evaluate <i>Leishmania</i> seroprevalence in livestock to assess its impact on leishmaniasis epidemiology in an endemic area located in the Mediterranean region. A cross-sectional serological study screened livestock exposure to <i>L. infantum</i> and risk factors in Southern Spain. A total of 864 serum samples of clinically healthy sheep, goats, cattle, and pigs were examined by an indirect fluorescence antibody test, using a 1/80 cut-off titre to minimize cross-reactions. Global seroprevalence was 10.8%: 21.6% cattle, 15.4% sheep, 7.3% goats, and 0.6% pigs. Statistically significant differences in positive detection were observed among species (<i>p</i> < 0.001) and natural regions (<i>p</i> < 0.001). High positive reactions in cattle, goats, and sheep suggest livestock exposure to <i>Leishmania</i> spp. and potential asymptomatic infection. Livestock presence in biotopes could promote a dilution effect, reducing human leishmaniasis incidence. Further investigation is needed to confirm livestock roles in leishmaniasis maintenance and transmission.