The diseases caused by apicomplexan parasites, which include the genera Toxoplasma, Neospora and Besnoitia, amongst others, cause significant production losses in livestock. In addition, toxoplasmosis is a relevant zoonosis in the EU and worldwide. The proposal developed by the grant candidate should be drafted under the aforementioned umbrella. The general goal of SALUVET's research lines is to apply innovative technologies (-omics, genome editing, ex vivo models) to explore host-pathogen interactions in some of the most relevant diseases caused by coccidian parasites in livestock. We hypothesize that the application of these technologies in a transversal approach can potentially unravel some of the molecular mechanisms underlying host-pathogen interactions. Three different but complementary approaches are pursued: i) exploitation of –omics technologies to (a) comparatively dissect processes involved in the adaptation of apicomplexan parasitesto their host, allowing them to actively replicate and disseminate, and (b) to understand parasite-host cell interactions in host target cells; ii) use of genome edition techniques to define the role of potential virulence factors that could define the host-pathogen interactions during infection; and iii) establishment and harmonization of relevant in vitro, ex vivo and in vivo disease models for studying experimental infections. The results obtained will advance the understanding of the mechanisms by which these relevant apicomplexan parasites interact with the host, which, in turn, will help in the design of transmission-blocking vaccines or drugs. This will have a positive impact on farm animal welfare, economic profitability of animal production, and exposure to harmful parasites, ultimately improving human health.