Detection of Leishmania (Mundinia) macropodum (Kinetoplastida: Trypanosomatidae) and heterologous Leishmania species antibodies among blood donors in a region of Australia with marsupial Leishmania endemicity

Objectives: The Australian Leishmania (Mundinia) macropodum parasite causes cutaneous leishmaniasis among marsupial species. Although cutaneous leishmaniasis is a major public health burden worldwide, it is not clear if humans are naturally exposed to the unique L. macropodum. To assess whether hu-mans have an immunoglobulin (Ig) G response to L. macropodum, we examined anti-Leishmania antibod-ies among humans residing in a region of marsupial Leishmania endemicity in Australia. Methods: Using a serological enzyme-linked immunosorbent assay, we characterized Leishmania-specific IgG and IgG subclass responses to soluble Leishmania antigen from L. macropodum, and other Leishmania species (L. donovani, L. major, and L. mexicana ) in 282 blood donor samples.Results: We found that 20.57% of individuals demonstrated a positive total IgG response to L. macrop-odum. For individuals with antibodies to soluble Leishmania antigen from one Leishmania species, there was no increased likelihood of recognition to other Leishmania species. For samples with detectable L. macropodum IgG, IgG1 and IgG2 were the prevalent subclasses detected. Conclusion: It is not yet clear whether the IgG antibody detection in this study reflects exposure to Leish-mania parasites or a cross-reactive immune response that was induced against an unrelated immunogen. Future studies should investigate whether L. macropodum can result in a viable infection in humans. (c) 2022 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

Automated summary

This study examined whether humans have an immunoglobulin G (IgG) response to the Leishmania (Mundinia) macropodum parasite, which causes cutaneous leishmaniasis among marsupial species in Australia. The results showed that 20.57% of individuals demonstrated a positive IgG response to L. macropodum. However, it is unclear whether this IgG antibody detection reflects exposure to Leishmania parasites or a cross-reactive immune response to an unrelated immunogen.