A cross-sectional serosurvey using Leishmania infantum ELISA was performed on 445 cats living in ecoregions around the Northwestern Mediterranean basin; 58 cats from an area of the US where leishmaniasis is not endemic were used as negative controls. ELISA results were further confirmed in 69 cats by Western blot (WB). Finally, 76 of them were also tested for FeLV and FIV. Seroprevalence by ELISA-prot A was 6.29%, and that by ELISA-IgG was 5.25%. Positive cat sera recognized patterns of polypeptides in WB, including L. infantum-specific antigenic fractions. There was no association with retroviruses. Leishmania-specific antibodies are prevalent in cats living in ecoregions around the Northwestern Mediterranean basin; thus, leishmaniasis must be included in the differential diagnosis of diseases in cats living in these ecoregions. Their role as peridomestic reservoirs for L. infantum needs further characterization, but it could be hypothesized that the cat is a secondary reservoir host, rather than an accidental one.

There is no gold standard for diagnosing leishmaniases. Our aim was to assess the operative validity of tests used in detecting Leishmania infection using samples from experimental infections, a reliable equivalent to the classic definition of gold standard. Without statistical differences, the highest sensitivity was achieved by protein A (ProtA), immunoglobulin (Ig)G2, indirect fluorescenece antibody test (IFAT), lymphocyte proliferation assay, quantitative real-time polymerase chain reaction of bone marrow (qPCR-BM), qPCR-Blood, and IgG; and the highest specificity by IgG1, IgM, IgA, qPCR-Blood, IgG, IgG2, and qPCR-BM. Maximum positive predictive value was obtained simultaneously by IgG2, qPCR-Blood, and IgG; and maximum negative predictive value by qPCR-BM. Best positive and negative likelihood ratios were obtained by IgG2. The test having the greatest, statistically significant, area under the receiver operating characteristics curve was IgG2 enzyme-linked immunosorbent assay (ELISA). Thus, according to the gold standard used, IFAT and qPCR are far from fulfilling the requirements to be considered gold standards, and the test showing the highest potential to detect Leishmania infection is Leishmania-specific ELISA IgG2.

Background. Amphotericin B (AmB), the most effective drug against leishmaniasis, has serious toxicity. As Leishmania species are obligate intracellular parasites of antigen presenting cells (APC), an immunopotentiating APC-specific AmB nanocarrier would be ideally suited to reduce the drug dosage and regimen requirements in leishmaniasis treatment. Here, we report a nanocarrier that results in effective treatment shortening of cutaneous leishmaniasis in a mouse model, while also enhancing L. major specific T-cell immune responses in the infected host. Methods. We used a Pan-DR-binding epitope (PADRE)-derivatized-dendrimer (PDD), complexed with liposomal amphotericin B (LAmB) in an L. major mouse model and analyzed the therapeutic efficacy of low-dose PDD/LAmB vs full dose LAmB. Results. PDD was shown to escort LAmB to APCs in vivo, enhanced the drug efficacy by 83% and drug APC targeting by 10-fold and significantly reduced parasite burden and toxicity. Fortuitously, the PDD immunopotentiating effect significantly enhanced parasite-specific T-cell responses in immunocompetent infected mice. Conclusions. PDD reduced the effective dose and toxicity of LAmB and resulted in elicitation of strong parasite specific T-cell responses. A reduced effective therapeutic dose was achieved by selective LAmB delivery to APC, bypassing bystander cells, reducing toxicity and inducing antiparasite immunity.