Parasitism, infection, infestation, intoxication. Zoonotic diseases and human diseases. Evolutionary adaptations in host-pathogen interactions. The paradigm of the origin of eukaryotes as an evolutionary endpoint of parasitism. Socio-cultural and environmental factors implicated in the origin and diffusion of pathogens and parasites in different historic and geographic contexts. The role of zoonotic diseases in the adaptation of new pathogens to the human species.

Mechanisms and barriers of natural defense in different external and internal surfaces of the human body. Transmission modes of infectious agents. Arthropods as vectors. Virulence factors. Toxins: biphasic and cytolitic exotoxins, endotoxins, targets and mechanisms of damage. Endotoxic shock: definition, risk factors and pathogenesis.

Concept of prion. History of the discovery of prions and their role as infectious agents. Exogenous, endogenous and hereditary prionic diseases. Mechanisms of damage induced by prionic proteins. Reticular stress, apoptosis and secretion.