Overview of Commercial Vaccines Against Canine Visceral Leishmaniasis: Current Landscape and Future Directions.

Visceral leishmaniasis is a zoonosis commonly caused in Brazil by the parasite Leishmania infantum. This protozoan parasite can infect several species of mammals, with dogs being the main reservoir in urban areas. Several methods are used to prevent the disease, including collars impregnated with 4% deltamethrin to prevent contact between the sandfly and the animal, and vaccines. Vaccines aim to stimulate an immune response that can effectively fight the parasite, with the Th1 immune response being the most desired. There are several research groups around the world dedicated to testing new immunogens against Leishmania spp. and there are currently two commercially available vaccines used to prevent the disease, Neoleish® and Leti-Fend®. Leish-Tec®, a vaccine previously licensed for use in dogs in Brazil, was suspended in May 2023 due to non-compliance in some batches. This also happened with CaniLeish®, which was discontinued by the European Commission in October 2023. These vaccines have different characteristics that influence their use as a public health measure, and therefore the objective of this review is to describe these immunogens, their characteristics, and their use as a collective prevention measure for canine visceral leishmaniasis.