The liver of all animals exhibited a variable degree of mixed cellular (neutrophils, lymphocytes and macrophages) portal inflammatory infiltration, where T cells and B cells were present in equal amounts. No difference in the severity of the inflammatory infiltration was apparent between sub-adults (n = 18) and adults (n = 22; Wald = 0.03, ns), or between males (n = 22) and females (n = 18; Wald,0.01, ns). Infiltrates often occurred together with follicle-like accumulations of lymphocytes, which occasionally exhibited germinal centres.