Figure 4. Histopathological changes in liver and spleen following infection with S. Typhimurium ST313 or ST19.

Photomicrographs (×400 magnification) of histological changes in H and E in fixed splenic and liver sections at seven days post infection. Both ST313 (D23580) and ST19 (4/74) infection result in hepatosplenomegaly as shown by the influx of inflammatory cells, and this is greater in ST313 infection. Infection also results in granuloma-like lesions typical of avian salmonellosis, which are larger and more numerous in the ST313 infected birds. Black arrows indicate granuloma-like lesions and white arrows indicate heterophil influxes. Scale bar = 100 µm.