Leishmaniosis: New Insights in a Changing World

Canine leishmaniosis caused by Leishmania infantum is a zoonotic disease of serious veterinary concern in the Mediterranean basin. In Portugal has been reported in dogs, cats and synanthropic rodents. Epidemiological changes and new hosts may contribute to increase zoonotic risk. A better knowledge on immune response, treatment and diagnosis are at the forefront of research on this disease. Host immune response is multifactorial, reflecting the organ specificity. Macrophages (MO) are the definitive host cells, although neutrophils (PMN) are the first cells to encounter parasites soon after inoculation in the dermis. The PMN-parasite interaction decreases parasite viability, but PMN-MO interaction induces nitric oxide production and release of neutrophil extracellular traps that contain parasites, controlling dog infection at early stages. Liver resident Kupffer cells (KC) efficiently phagocyte Leishmania by establishing an intimate contact with circulating blood. The impact of meglumine antimoniate (MG) over infected canine KC was investigated. The effect of different treatment protocols in dog’s immune response was assessed. MG+miltefosine treatments plus allopurinol restore lymphokine gene expression, pointing through a drug-induced reduction of anti-inflammatory and regulatory cytokines. Furthermore, increasing feline leishmaniosis and the inconsistent results of therapeutic protocols led the team to evaluate their safety and effectiveness in cat.