From 2003–2014, there were 38 cases of pyometra in a captive exotic felid collection of over 300 non-domestic felids, including 11 previously reported cases.1 Fisher’s exact tests were used to compare prevalence, and student’s t-tests were used to compare means. The prevalence of pyometra in lions (Panthera leo; 13/30, 43.3%) was significantly greater than that in tigers (Panthera tigris; 21/128, 16.4%; p=0.0026). Only one tiger was known to have received contraception prior to developing pyometra. The average (±SD) age of the tigers at time of diagnosis (12.6±2.8 years) was significantly greater than that of lions (10.15±2.38 years; p=0.0145). One lion died under anesthesia for ovariohysterectomy, and one tiger was found dead secondary to pyometra. The outcome after ovariohysterectomy overall was good. Average lifespan after treatment was not significantly different between lions and tigers, with a mean of 3.57±2.01 and 2.81±2.10 years, respectively (p=0.49). White blood cell counts were significantly greater in lions (30.2±13.5×103) than in tigers (16.3±7.2×103; p=0.0008). On histopathology, lions had a statistically significant increase in frequency of cystic endometrial hyperplasia (CEH) compared to tigers (p=0.0248). There was no significant difference between the frequency of lions and tigers with at least one corpus luteum present on at least one ovary (p=0.4706). These findings show that lions are at an increased risk for developing pyometra as compared to tigers, possibly due to increased risk of CEH development.
The authors thank the staff at Tiger Haven for their dedication to the treatment of animals under their care, and for all of the people at the University of Tennessee who contributed to the medical treatments of these animals.
1. McCain S, Ramsay E, Allender MC, Souza C, Schumacher J. Pyometra in captive large felids: a review of eleven cases. J Zoo Wildl Med. 2009;40(1):147–151.