Bacterial persistence in spleen, liver and caecal tonsils. The total amount of viable bacteria was quantified from internal organs at week 16 pi. Data is presented as mean CFU/gram tissue ± standard error of the mean. Individual data points have also been included to highlight the variation within each group. In splenic samples, bacterial loads in birds infected with only Salmonella Typhimurium were significantly higher than the titre observed in the co-infection group (*p < 0.01). Only 2/14 liver samples from the Salmonella Typhimurium treatment group were positive for bacteria, while 13/14 positive samples were detected for co-infected birds. The mean for the liver was significantly higher in the co-infection group (*p < 0.01). No significant difference was detected in bacterial loads from the caecal tonsils.