Serologic Survey and Results of Urinary PCR Testing for Leptospirosis in Captive Black-Tailed Prairie Dogs (Cynomys ludovicianus)
Abstract
Leptospirosis is an important zoonotic disease occurring clinically and subclinically in humans and a wide variety of mammalian species worldwide.1,7 Rodents and wild animals have been identified as important reservoirs for Leptospira bacteria.2,3,5,8,10,12-16 Twenty-two captive black-tailed prairie dogs (Cynomys ludovicianus) housed within a zoo were examined as part of a routine census and preventive medicine program. During examinations, blood and urine were collected to test for evidence of infection by Leptospira. All animals were apparently healthy at the time of examination. Leptospira microscopic agglutination test (MAT)6 identified twelve of 22 (54.5%) prairie dogs with Leptospira interrogans serovar Bratislava on initial serologic examination. All prairie dogs within this collection were serologically negative for Leptospira interrogans serovars Canicola, Hardjo, Icterohemorrhagiae, Pomona, and Leptospira kirschneri serovar Grippotyphosa. Leptospira PCR11 testing of urine was negative in all animals tested. A recent serologic survey of wild black-tailed prairie dogs in Mexico determined that almost 80% of wild prairie dog sera were positive for at least one L. interrogans serovar.9 This report suggests that these captive prairie dogs may have been exposed to Leptospira; however, low MAT results and lack of leptospire DNA detected by PCR indicate these animals are unlikely to be important reservoirs for the disease. We hypothesize the source of Leptospira exposure to be wild rodents.
Acknowledgments
The authors thank Yuxuan Sun, Department of Statistics, College of Liberal Arts and Sciences, Iowa State University, for statistical analysis. Heartfelt gratitude is also extended to the veterinary support team, small mammal team, and registrar of the Blank Park Zoo for excellent record keeping and tireless care for these wonderful animals.
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