**1. Introduction**

*Salmonella* is a species in the genus with worldwide public health implications and is the major cause of foodborne disease, accounting for deaths of thousands of people worldwide [1–9]. *Salmonella* is anaerobic in nature and is a Gram-negative, rod-shaped bacterium belonging to the Enterobacteriaceae family. *Salmonella* is divided into two species: *Salmonella enterica* and *Salmonella bongori*. More than 2600 *S. enterica* serovars have been defined so far, with most of these serotypes likely to cause diseases in both humans and animals [10], whereas a few *S. enterica* variants, such as *Salmonella* Gallinarum (SG) and *Salmonella* Pullorum (SP), are non-flagellated and non-motile, the large percentage of *Salmonella* members are motile by peritrichous flagella. The SG and SP are linked to clinical disease in poultry

**Figure 1.** *Sources of Salmonella enterica.*

and cause significant economic losses to poultry farming, particularly in developing countries [11–13]. According to recent data from the United States, Europe, and Low and Middle Income Countries (LMICs), *Salmonella* is frequently occurring international cause of foodborne disease. *Salmonella* also enhances food contamination in many natural environments [14]. *Salmonella enteric* found in the gut of food animals more persistently, is characterized by chronic transmitters which remove the bacterium with their own fecal matter. As a result, these carriers act as a reservoir for future bacterial contamination, allowing *Salmonella* to spread through infected milk, meat, eggs, and other agricultural products fertilized and developed in *Salmonella*-infested manure [14]. *Salmonella* have been isolated from variety of animals and their food products. These include poultry, ovine, porcine, bovine, lizards and snakes (**Figure 1**). This book chapter attempts to discuss different aspects of *Salmonella* serovars and *Salmonella* infection in different animals, with special emphasis to understand the mechanism of its pathogenesis.
