Pathogenicity of Some Avian Salmonella Serovars in Two Different Animal Models: SPF- Chickens and BALB/c Mice

The pathogenicity of Salmonella Kentucky, Salmonella Typhimurium, Salmonella Shubra and Salmonella Enteritidis were investigated in specific-pathogenfree chicks (SPF) and BALB/c mice. Mortality rates after the 1 st week of infection with the four serovars, only S. Typhimurium and S. Enteritidis produced a fulminate infection (88%) in each of the chicks and mice. The lowest mortality was seen in chicks and mice inoculated with S. Kentucky (40% and 44% respectively,). Over 40% mortality was observed in SPF chicks (45.8%) and BALB/c mice (60%) inoculated with Salmonella Shubra. The lethality of S. Typhimurium in mice was 66% while S. Enteritidis was lethal to chicks by 72%. Analysis of the level of fecal shedding of the four serovars from both infected SPF chicks and infected BALB/c mice revealed that, S. Typhimurium was consistent in being the highest in re-isolation rate throughout the 7 days of observation while, S. Enteritidis comes second in re-isolation rate. A variable re-isolation picture was noticed from S. Kentucky and serovar Shubra throughout the experimental period. The highest level of re-isolation was on the 1 st day post infection (DPI) recorded as 60%, 40% and 20% from the serovars Enteritidis, Typhimurium, Shubra and Kentucky, respectively.