Pathogenicity and Reservoir Potential of Salmonella enterica serovar Rissen in Murine Models: Implications for Environmental Dissemination

This research was conducted to study the pathogenicity of Salmonella enterica serovar Rissen in mice and its potential role in rodents as reservoirs for its environmental dissemination. A total of 18 mice divided into infected group which were group A and B which consisted of six mice each. Necropsy was conducted on day 2 and day 5 post-Infection (PI). The control group consisted of three mice day 2, and three mice day 5 for necropsy. The control group was given 0.1ml of normal saline. While the infected group was given 0.1ml of 4.9 x 109 CFU Salmonella enterica serovar Rissen orally. The study showed that infection of S. enterica serovar Rissen in mice caused enteric lesions and systemic infection. Salmonella enterica serovar Rissen did not cause diarrhea and mortality but depression during the period of the experiment. All infected mice showed reddened serosal layer of the small intestine especially in the jejunum and ileum. Histopathology analysis of these organs revealed hemorrhagic enteritis, hemorrhagic cecities, cecities, colitis, interstitial nephritis, hemorrhagic hepatitis and splenitis. Salmonella enterica serovar Rissen was isolated from the kidney and spleen 2 days PI, and from the urine and kidney of the mice 5 days PI through PCR confirmation. The clinical signs and histopathological findings highlight the organism's impact on multiple organs, particularly the intestines, liver, and kidneys. The successful isolation of the pathogen from various tissues supports the hypothesis that rodents, including mice, may act as reservoirs for this serovar, posing risks for environmental dissemination.