Dose-dependent progression and physiological impact of <i>Salmonella typhi</i> infection in albino rats

The progression of typhoid fever was investigated in Albino rats experimentally infected with Salmonella typhi at Ebonyi State University, Abakaliki. A total of 20 albino rats were divided into five groups, each containing four rats. Group A served as the negative control, while Groups B, C, D, and E were infected with increasing doses of Salmonella corresponding to 0.5, 1.0, 1.5, and 2.0 McFarland suspensions, respectively. Group E, which received the highest dose (2.0 McFarland suspension), exhibited notable changes during the experiment. During the acclimatization period, the mean weights were 80.0±0.0 g and 91.4±8.3 g for weeks one and two, respectively. Following infection, the mean weight stabilized at 100.0±0.0 g from days 1 to 3 but declined to 99.0±2.3 g from days 4 to 6, indicating significant weight loss post-infection. Similarly, temperature fluctuations were observed in Group E. During acclimatization, the mean temperature was 35.25±0.25°C, rising to 39.36±0.30°C to 40.7±0.30°C during the infection period, before decreasing to 39.4±0.28°C on the final day of the experiment. The study concludes that the severity of infection is dose-dependent, with a 2.0 McFarland suspension required to induce infection in Albino rats. Furthermore, the results indicate that the progression to overt disease in experimental rats occurs within 4–6 days post-infection.