**4.2 In livestock**

Salmonella infections can be seen in reptiles such as turtles, lizards, and snakes; birds like domestic pigeons and parrots; amphibians such as frogs and mammals such as dogs and cats. These infections are not frequent in small captive animals. Infection may be undetectable in reptiles, canines, and kittens although Salmonella could be identified in the stools of healthy animals. The guts of some animals can happily support these creatures which become the carrier animals of *Salmonella*. Diarrhea and enteritis are the common symptoms of Salmonellosis. Septicaemia can also be caused by *Salmonella's* invasion in the host. This intrusion causes rise in body temperature, which is usually associated with *Salmonella* infection-induced enteritis. Drowsiness, loss of appetite and diarrhea are the clinical signs of *Salmonella* infection. The diarrhea could be severe, and typically domestic dogs and cats could become extremely ill and unknowingly pollute the residence. While in birds, this disease is seldom visible. However, animals or birds that are juvenile, aged, or weak may be badly harmed by the diarrhea-induced exhaustion. They develop sepsis and expire. Most of the affected organisms may experience diarrhea for a short period of time but the majority make a full recovery. Any recuperating animal can act as a vector of infection for a period of time. *Salmonella* can dwell in low numbers in the gastrointestinal system and lymphatic system, especially in locations like caecum of birds. *Salmonella* infection may recur if the organism develops another disease [42].

## **4.3 In domestic fowl and poultry**

*Salmonella* causes four types of infections in poultry, all of which are serious: Pullorum serovars of *S. enterica* causes Pullorum disease, *S. Gallinarum* causes fowl typhoid, arizonae subspecies of *S. enterica* causes arizonosis [43] and several subspecies of Salmonella like *S.* Infantis, *S*. Enteritidis and *S*. Typhimurium cause paratyphoid. The unique *S. enterica* serovars Pullorum and Gallinarum seen in poultry have been largely eliminated from European and North American industries. Nonetheless, these serovars pose a greater hazard to avian safety and wellness in areas of the globe which have low industry development, particularly in areas with inadequate

protection. Despite the fact that these two serovars of *S. enterica* are normally found in chicks, spontaneous occurrences caused by these serovars. Residential chicken are among the major reservoirs of this bacteria, posing a risk to human health through the intake of contaminated foods have indeed been reported in other birds like guinea fowl and turkeys.

Poultry products have been found as a major origin of Salmonellosis on numerous occasions. Across the year 2000, an approximate 182,060 Americans were sick with *S.* Enteritidis after eating tainted eggs [44]. During 1985 and 1999, eggs were blamed for about 80,010 *S.* Enteritidis cases in the United States [45]. In addition, consumption of infected chicken has been recognized as a major potential cause for *S*. Enteritidis transmission [46]. Several of the serovars which are frequent in humans are also abundant in poultry, demonstrating the relevance of livestock as a source for the spread of *Salmonella* in people [47]. *Salmonella's* potential to infect chicken is highly linked to the transmitting serotype, as well as the maturity and genetic lineage of the bird. The disease caused by Gallinarum serovar of *S. enterica*, Fowl Typhoid (FT) spreads mostly through fecal-oral route [48]. There are also diseases mostly restricted to the gut caused by different *Salmonella* serovars in poultry [43]. Salmonellosis is the most common symptom of Typhimurium serovar infection in small birds. Fatality rates differ greatly, ranging from as low as 10% to as high as 80% in extreme cases.

#### **4.4 In cattle**

Salmonellosis is a leading cause of death and disease in livestock, some of which are commonly detected which are infected sub-clinically. As a result, cattle serve as a significant storehouse for diseases infecting humans. Several studies have been published during last decade with an emphasis on multi drug resistance variants and significance of *Salmonella* for food sector [49, 50]. Surprisingly, although extensive research was done on Salmonellosis, the infection and its associated risks remain unaddressed [43]. Salmonellosis is still a disease that affects livestock all over the world and is largely caused by the *S.* Dublin and *S.* Typhimurium. Additional serotypes have been linked to cattle infections on a stochastic basis [48]. Studies documented the identification of 101 distinct serotypes of Salmonella in cattle, most of which had a reduced incidence [43, 51]. In late 1960s, *Salmonella* infections in the livestock sector of Britain peaked with over 4000 cases reported in 1969 [48, 51]. Seven (07) serovars of *Salmonella* were found in 48% of the 730 isolated *Salmonella* from livestock in the United States [50]. There is a risk of novel strains being imported which was reported in United Kingdom as 10 *Salmonella* serovars were identified which were of non GB origin [43].

#### **4.5 In pigs and sheep**

*S. enterica* serovars Choleraesuis was first detected in swine when it was thought to be the causative agent of swine fever (hog cholera). The susceptibility of swine to *Salmonella* is determined by a number of parameters like the infecting serotypes and the pig's age. Further, the incidence of Salmonellosis varies from region to region and is weakly linked to swine population, farming techniques, and their mixing [43]. *Salmonella* serovars linked to clinical illness in swine can be separated into two categories: Choleraesuis like host specific serovars and *S.* Typhimurium like ubiquitous. However, the presence of *S.* Choleraesuis has substantially decreased since then, and it is currently only spotted occasionally whereas Typhimurium still remains a severe

#### Salmonella *Infection and Pathogenesis DOI: http://dx.doi.org/10.5772/intechopen.102061*

threat to the swine sector especially in United States. Several serovars like Typhimurium, Copenhagen, Agona, Derby and Heidelberg were by far the most prevalent serovars in swine in the United States in the first decade of this century. Three of these serovars were isolated from humans during this time span [52]. During last 02 decades, research studies on other serovars have increased either due to improved surveillance or due to increased occurrence of infection.

Sheep Salmonellosis appears to be frequent in nations with considerable sheep population, including United Kingdom, Australia, New Zealand, and the United States of America. The seasonality of Salmonellosis spread and the incidence of diseases caused by widespread serovars is usually linked to sheep mobility and transportation [53, 54]. The Ovis strains of Serovar Abortus with restricted hosts are predicted to be introduced into diseased sheep flocks and spread *via* the fecal oral route [55]. However, there is no strong evidence that bacteria are transferred by drinking, nutrition, or the wastes of other hosts. Transmission of grazing livestock through the nasal channel may be possible due to many serovars causing pneumonia in lamb. Pulmonary discharge may transmit the bacteria to other animals.

### **4.6 In horses, dogs and cats**

*Salmonella* Typhimurium was initially reported as the causative agent of Colitis in late 1910 and subsequently prevailed as a cause of Salmonellosis in horses throughout the world. Antibiotic use in conjunction with hospitalization stresses has been shown to have a significant impact on the horse's sensitivity to *Salmonella* infection. The only host suitable for hooved animals is *Salmonella* Abortusequi, which causes horse paratyphoid disease. The surge and decline in prevalence of disease by distinct serovars has become a significant characteristic of the epidemiology of horse salmonellosis in the United States. This could lead to an increase in herd immunity and decrease in the pathogenicity of the individual serovar.

*Salmonella* infection in cats and dogs can be subclinical, with just occasional shedding. The infection fluctuates, ranging from moderate to severe gastritis, with the possibility of miscarriage, systemic dissemination, or sepsis [56]. *Salmonella* can be excreted over a month by healed animals, and persistent transmission with intervals of re-emergence is conceivable. *Salmonella* have the ability to propagate zoonotic infections and may play a role in the establishment of antibiotic resistance in bacteria [57]. The majority of the infestations were medically quiet, however some developed moderate diarrhea. Recent research has shown that dogs fed with uncooked meat can eliminate the bacterium in their stools for a longer period.
