Abstract
Nineteen cases of cystitis were diagnosed at necropsy and/or by histology in a group of 170 (96 females, 74 males) guineapigs (11·2%). Seventeen of the 19 cases (89·4%) were females. The mean age of guineapigs with cystitis was 34·7 months, which was higher than the mean age of 24 months of the 170 members of the study group. In addition, 6 cases of urolithiasis and cystic calculi in 5 females and one male were also found in the 170 guineapigs (3·5%). The mean age of the 6 cases was 30 months, which was also higher than the mean age of the 170 animals. The study suggests that aged female guineapigs were much more predisposed to cystitis and urolithiasis or cystic calculi than male and young guineapigs. The cause may be related to infection with Escherichia coli and Staphylococcus sp, cystic calculi, diabetes mellitus and female guinea pig urogenital anatomy and function.