Pathogenic Leptospira species are the cause of leptospirosis—a global zoonotic disease. Maintenance hosts, such as dogs, rats, and cattle, may not exhibit clinical signs but may be shedding infectious leptospires into the environment. This study evaluated the use of a quantitative real-time polymerase chain reaction specific for LipL32 to detect urinary shedding of leptospires from dogs. The LipL32 is a gene that encodes the outer membrane lipoprotein present in pathogenic leptospires but absent in saprophytic species. The assay was applied to urine samples from local dog sanctuaries in Dublin (27 samples) and the University Veterinary Hospital at University College Dublin (498 samples). A total of 37 were positive, which made the prevalence of urinary shedding of leptospires 7.05%. In the U.S., leptospiruria has been demonstrated in 8.8% of dogs. There is a need to raise public health awareness of this disease and provide effective vaccination strategies.

Commentary: Leptospirosis is considered a reemerging infectious disease of dogs in the U.S. Since it is no longer a reportable disease in people, it is difficult to know the exact incidence; however, in recent years cases associated with outdoor and recreational activities have been reported. In dogs, clinical signs of disease vary greatly, ranging from carriers (those with no clinical signs) to those with acute signs, including fever, vomiting, pulmonary hemorrhage, and shock, to chronic disease with hepatic and renal dysfunction. Vaccination programs are a crucial component to prevent and control this zoonotic threat.—Patricia Thomblison, DVM, MS

Detection and quantification of leptospires in urine of dogs: A maintenance host for the zoonotic disease leptospirosis. Rojas P, Monahan AM, Schuller S, et al. EUR J CLIN MICROBIOL INFECT DIS 29:1305-1309, 2010.