Protozoan infections, caused by parasites such as Plasmodium, Trypanosoma, and Leishmania, continue to pose significant public health challenges worldwide. Malaria, caused by Plasmodium spp., alone affects millions of individuals annually. The development of effective vaccines against protozoan infections is a complex endeavor due to the intricate life cycles of these parasites and their ability to evade the host immune system. One notable example is the ongoing efforts to develop a malaria vaccine. The most advanced candidate, RTS,S/AS01, targets the sporozoite stage of the Plasmodium falciparum parasite. Despite progress, challenges such as the parasite's ability to mutate and the complexity of the host immune response hinder the development of highly effective vaccines. Ongoing research focuses on understanding the immunological mechanisms involved in protozoan infections to inform vaccine design. The success of vaccines against bacterial and viral pathogens has spurred increased interest in protozoan vaccine development. Innovative approaches, including the use of subunit vaccines, viral-vectored platforms, and adjuvants, are being explored. Collaborative efforts between researchers, governments, and non-governmental organizations are essential to overcome the scientific, financial, and logistical challenges associated with protozoan vaccine development. Pseudoterranova Infection. The life cycle of Pseudoterranova involves complex interactions between definitive hosts (marine mammals) and intermediate hosts (various fish species). Humans become accidental hosts when they consume infected intermediate hosts. The distribution of Pseudoterranova infections is influenced by the abundance and migratory patterns of marine mammals, as well as the consumption habits of local populations. Regions with high consumption of raw or undercooked seafood, such as sushi or ceviche, may have a higher prevalence of anisakiasis. Coastal areas with a significant marine mammal population, including the North Pacific, North Atlantic, and Southern Ocean, are considered hotspots for Pseudoterranova infections. Climate change and alterations in marine ecosystems may also impact the distribution of these parasites and, consequently, the risk of human infections.