At the start of the simulation, one infection is introduced into the fully susceptible population. To avoid bias between simulations, the initial infection is distributed over all age and risk classes. DNA Vaccines against Protozoan Parasites: Advances and Challenges Over the past 15 years, DNA vaccines have gone from a scientific curiosity to one of the most dynamic research field and may offer new alternatives for the control of parasitic diseases such as leishmaniasis and Chagas disease. We review here some of the advances and challenges for the development of DNA vaccines against these diseases. Many studies have validated the concept of using DNA vaccines for both protection and therapy against these protozoan parasites in a variety of mouse models. The challenge now is to translate what has been achieved in these models into veterinary or human vaccines of comparable efficacy. Also, genome-mining and new antigen discovery strategies may provide new tools for a more rational search of novel vaccine candidates. In spite of the success of vaccines in public health, there are still numerous pathogens, and in particular protozoan parasites such as Plasmodium falciparum, Trypanosoma sp., or Leishmania sp. against which there are still no effective vaccine. However, the discovery that the direct injection of plasmid DNA encoding foreign proteins could lead to endogenous protein biosynthesis and a specific immune response against it opened new perspectives in vaccine development. Over 15 years later, DNA vaccines have gone from a scientific curiosity to one of the most dynamic fields of research and may offer new alternatives for the control of infectious diseases [1] . Indeed, the first two DNA vaccines have been licenced, in recent years, to protect horses from west nile virus and salmons from infectious hematopoietic necrosis virus, confirming the usefulness of this biotechnology. We review here some of the advances and challenges for the development of DNA vaccines against two well-studied protozoan parasites, Leishmania sp. and Trypanosoma cruzi. Both belong to the trypanosomatidae family and are ranked among the three major protozoan parasites affecting humans. Leishmaniasis is a complex disease caused by at least 18 species of parasites from the Leishmania genus and transmitted to humans by hematophagous sandflies. With an estimated 12 million cases, it has a major public health impact in several regions, and in particular in India, Sudan, and Brazil [2] .