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Canine Leptospirosis: The Best Treatment Remains Prevention

Infectious Disease


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Canine Leptospirosis: The Best Treatment Remains Prevention
Sponsored by Merck Animal Health 

Leptospirosis is a zoonotic bacterial infection that can be found throughout most of the United States. Dogs can be exposed to leptospires from soil, water, and fomites contaminated with infected urine and become infected when bacteria enters the mucous membranes.1 After an incubation period, spirochetes ultimately reside in renal tubules, resulting in urinary shedding. Apparently healthy dogs may shed leptospires in their urine for weeks to months if unidentified and untreated, causing further contamination and increasing the risk for spreading infection.

Due to factors such as climate change, population growth, and habitat encroachment, reports of canine leptospirosis are on the rise and expected to continue to increase.2,3 Therefore, appropriate biosecurity, biosurveillance, and prevention measures are more imperative now than ever when diagnosing and treating patients with leptospirosis.

Urinary Shedding

Urinary shedding in infected patients begins 7 to 10 days after infection and ceases 2 to 3 days after initiation of appropriate antibiotic therapy.4 Shedding can also occur in clinically healthy dogs (ie, subclinical carriers). Leptospires can persist in renal tubules for weeks to months, resulting in the potential for a chronic carrier state.5 In a study, 8.2% of study dogs were found to be shedding pathologic leptospires, regardless of their health status.6 Thus, subclinical shedding is likely a larger contributing factor to the spread of leptospirosis and therefore a larger risk to public health than may be expected.6,7

Biosecurity & Biosurveillance

Because leptospirosis suspects may not be easily identified, routine use of appropriate biosecurity protocols is advised if there is any reason to be suspicious of leptospirosis. Recommendations should be focused on urinary shedding and include urinary catheterization, restricting walks, minimizing patient movement in hospital, appropriate patient labels advising staff of handling instructions and potential for zoonotic/contagious infection, and frequent hand washing and use of personal protective equipment.4


Leptospirosis vaccination may be considered a noncore, risk-based vaccine in some areas. However, development of subclinical leptospirosis is common, which may create the impression of a lower incidence than is actually the case, especially if testing is infrequent. Vaccination against leptospirosis can help in preventing infection; however, no vaccine is 100% effective against subclinical infection, and not all vaccines are labeled to help prevent urinary shedding. Nobivac® Lepto 4 has been shown to be effective against urinary shedding and to decrease mortality associated with leptospirosis.8,9 Prevention of urinary shedding is the best measure to decrease the risk for infection in both animals and humans, ultimately decreasing the risk for transmission of an infection that has the potential to result in fatal illness.



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