Infectious diseases are caused by a pathogenic microorganism (virus, bacterium, parasite or fungus) and have a significant impact on public and animal health. In public health, they are one of the leading causes of death and are priorities in the poorest countries. In animal health, they can be devastating and radical measures are taken to prevent them from spreading. Infectious diseases therefore have major economic consequences, in terms of both healthcare and livestock production losses. In recent decades, we have seen the emergence of a significant number of infectious diseases, such as chikungunya, avian influenza and Ebola. These diseases have spread around the world all the more dramatically due to the rapid movement of populations and goods. The majority of pathogenic agents responsible for these emergences are zoonotic (transmitted from animals to humans or vice versa). There has also been a significant increase in vector-borne diseases – that is diseases whose pathogenic agent is transmitted through the intermediary of a vector. Vectors are arthropods (e.g. mosquitoes, fleas, sand flies and reduviid bugs) and acarids (e.g. ticks). One example is the mosquito Aedes albopictus, more commonly known as the "tiger mosquito", which is a vector for the chikungunya and dengue viruses. The geographical distribution of this mosquito is increasing year by year. This species was responsible for the first indigenous cases of chikungunya in France in 2010.