Salmonella is a genus of highly diverse bacteria that live in the intestinal tract of humans and animals and are widespread in the environment thanks to their ability to survive and adapt even under extreme conditions.
The more than 2,600 Salmonella serovars are divided into typhoidal and non-typhoidal serovars and all of them are potentially harmful and can cause diseases in humans with different level of severity. Typhoidal serovars (S. Typhi and S. Paratyphi) are highly adapted to the human host, which constitutes their exclusive reservoir, so they are transmittable only through human-to-human contact, causing a potentially life-threatening syndrome known as typhoid or paratyphoid fever. Their prevalence is very low in high-income countries, and the few European cases that occur generally involve people returning from trips to low- or middle-income countries.
Non-typhoidal serovars are zoonotic agents. They are transmittable from animals and foods to humans, but also through human-to-human contact, and they can cause various syndromes, most of which are gastrointestinal. Due to its adaptability, Salmonella is widely prevalent in the environment and can infect animals and contaminate food.
The majority of circulating serovars are non-typhoidal and are the subject of this story map.