Pearsonema plica (Capillaria plica) infection and associated urinary bladder pathology in red foxes (Vulpes vulpes) from Bosnia and Herzegovina.

Pearsonema plica is a widely distributed nematode parasite that occurs in the urinary tract of various domestic and wild carnivores. The aim of this study was to investigate the occurrence and geographical distribution of P. plica and associated urinary bladder pathology in 112 red foxes (70 males, 42 females; 87 adults >1 year, 25 juveniles <1 year) from six different geographical regions in Bosnia and Herzegovina. The urinary bladders of the red foxes were subjected to gross examination and histopathology. Urine content (n = 40) and mucosal smears (n = 71) of the urinary bladders were examined microscopically for the presence of P. plica. Overall, adults and eggs of P. plica were detected in 65 (58.0 %; 95% CI 48.9-67.2%) of the foxes. Out of the positive foxes, 42 were males (64.6%) and 23 females (35.3%). According to age, 49 adults (75.3%) and 16 juveniles (24.6%) were positive. There were no statistically significant differences in the infection prevalence between the geographical regions (p = 0.701), sex (p = 0.693), or age (p = 0.646) of the host. Also, no significant differences in the prevalence of parasites in urine content (48.7%; 20/41) and mucosal smears (63.3%; 45/71) were observed (p = 0.165). Eosinophilic cystitis characterized with mild to severe infiltrates of eosinophils in the propria of the bladder mucosa accompanied by hyperemia and edema was observed in 36 examined foxes, 24 of which were P. plica positive. Parasites attached and embedded into the mucosa and free in the lumen were recorded in both cystitis positive and negative foxes. Beside clear numerical differences, the influence of P. plica infection on the occurrence of cystitis was not significant (p = 0.309). The results of this study give the first insight into the distribution of P. plica infection among the red fox population in Bosnia and Herzegovina. Observed microscopic changes may contribute toward a better understanding of pathology caused by this widely distributed parasite in free-ranging red foxes.