August is National Immunization Awareness Month, and The Meowing Vet wants to inform pet owners about the risk of Leptospirosis in unvaccinated dogs and how this zoonotic disease can cause kidney failure and liver disease in humans as well. Read more to learn how to protect your dog and yourself from this bacterial infection…
Click here to download your free educational pamphlet on Leptospirosis, courtesy of the American Veterinary Medical Association (AVMA). ⚕️
What Is Leptospirosis?
With a seeming increase in Leptospirosis outbreaks in 2016 and 2017 in several American states (particularly New Jersey and New York), pet owners worldwide need to stay informed. Leptospirosis (often referred to simply as “Lepto“) is caused by infection with the bacteria Leptospira interrogans.
Several pathogenic serovars (or variations) of this bacterial species exist, including L. interrogans australis, autumnalis, bratislava, canicola, grippotyphosa, hardjo, icterohaemorrhagiae, and pomona. Different serovars may be more or less common in various regions of the world. These serovars most often affect livestock (such as cattle) as well as wildlife, primarily rodents like mice and rats. Disease can also spread to dogs and humans from agricultural or wildlife animals, from dog to dog, or from dog to human.
While the canicola serovar is the most common form in canines and the type against which the Leptospirosis vaccine targets, dogs can be infected with other serovars as well, leading to disease. L. interrogans can also theoretically affect cats to a lesser extent, though infection with disease complications is less common.
How Is Leptospirosis Spread?
The Lepto bacteria is transmitted through the urine of infected cattle, wildlife, and other dogs. It primarily enters your body or that of your dog by penetrating mucous membranes (such as the oral and nasal passages) or by entering breaks in the skin. To a lesser extent, it can also be spread from dogs via the placenta (passed from mother to fetus during pregnancy) or venereal (genital) route. Lepto can also be acquired from ingesting infected tissues.
After the Leptospira bacteria invades the body of its new host, it replicates in the lining of blood vessels, primarily around the kidneys, liver, and muscles. This can lead to local inflammation and hemorrhaging as well as kidney failure and liver disease (discussed in more detail below).
What Dogs Are Most At-Risk?
Leptospirosis is also risk factor in cities, not just rural areas.
Any dog can potentially become infected with Leptospirosis. However, dogs at increased risk for Lepto infection are intact (un-neutered) male working dogs, primarily those that serve as herding or hunting dogs. These dogs are more likely to be in contact with urine of infected livestock and wildlife. Most cases of Leptospirosis occur in the summer or early fall when there are high levels of rainfall or stagnant pools of water, serving as perfect systems for collecting contaminated urine from other infected animals.
But don’t think that just because you live in an urban area away from agricultural livestock and most wildlife that you and your pup are protected from potential Leptospirosis infection. Cases of Leptospirosis are now more common in urban areas than in rural regions due to the increased chance of contact with rodents in city dwellings.
Before you go setting out mouse bait for pest control, read The Meowing Vet’s article on accidental rodenticide (rat poison) toxicity in dogs and cats. You’ll learn how to protect your pets from toxic rat bait and humane alternatives for rodent control.
Signs of Leptospirosis Infection
As stated, Leptospirosis primarily causes acute (or very sudden) kidney failure, liver disease, and blood vessel (or vascular) injury. Other organs such as the musculature, respiratory tract, central nervous system (CNS), and eye may also be affected.
The clinical signs of Leptospirosis that you may observe in your dog include:
- Fever
- Decreased appetite (anorexia)
- Lethargy or depression
- Gastrointestinal signs (secondary to toxin build-up in the bloodstream due to kidney and liver disease)
- Vomiting
- Diarrhea
- Abdominal pain
- Increased urination and water consumption (polyuria and polydipsia, or PU/PD, respectively), a sign of kidney failure (though sometimes oliguria, or producing only small amounts of urine, may initially occur)
- Dark or bloody urine
- Yellowing of the skin or white part (sclera) of the eyes (a.k.a. icterus or jaundice), a sign of liver disease
- Nondescript pain (due to myalgia or meningitis)
- Red eye(s) due to uveitis
- Bleeding or pinpoint bruising (petechia) under the skin or mucous membranes
- Coughing or difficulty breathing (respiratory distress)
If you observe the above signs in your puppy or adult dog, take him or her to the vet immediately!
A sudden increase in thirst and urination can be a sign of Leptospirosis infection.
Diagnosis
If you live in an area of high exposure to Leptospira bacteria and your dog is displaying signs of Leptospirosis, your veterinarian will likely already be suspicious of a Lepto infection. However, truly diagnosing Leptospirosis is sometimes a bit tricky since the clinical signs may resemble those of other disease processes and because no one perfect test exists. To save your dog’s life in the meantime, treatment is often initiated by your vet before a concrete diagnosis is reached.
Since all tests have their flaws, your vet may need to run several different tests, putting their individual results together to formulate a proper diagnosis, which can take time and money. Several of these tests utilize various methods (all with their pros and cons) for detecting different antibody formation by your dog’s immune system in response to Lepto exposure. Such tests include serology (which may be difficult to interpret if your dog has been previously vaccinated against Lepto), ELISA testing, and rapid immunochromatography (such as the new in-house WITNESS® Lepto test).
Polymerase chain reaction (PCR) may also be performed on a blood or urine sample to detect the presence of DNA from the Lepto organism. Performing a bacterial culture from a urine sample can also help detect the Lepto bacteria. If your dog is stable enough to undergo anesthesia, a renal biopsy may be taken for histopathology analysis to observe damage to the kidneys consistent with Leptospirosis infection.
Supportive diagnostic tools include routine bloodwork and urinalysis. Bloodwork will show signs of inflammation (leukocytosis, or high white blood cell count), often a mild anemia (or low red blood cell count), a low platelet count (thrombocytopenia), increased liver enzymes with hyperbilirubinemia (increased bilirubin in the bloodstream), and evidence of azotemia (high BUN and creatinine secondary to dehydration and kidney damage). Urinalysis will show evidence of kidney damage too: isosthenuria (inadequate urine concentrating ability by the kidneys) and inflammatory urine sediment.
Interested in learning how to interpret your dog or cat’s labwork? Read The Meowing Vet’s “how-to” guides below:
You Smarty Pants!: How to Interpret Your Pet’s Bloodwork
The Golden Rule: How to Interpret Your Pet’s Urinalysis
Treatment
Treatment primarily involves IV fluid therapy to support the body in the face of kidney and liver disease as well as IV antibiotics to rid the Leptospira bacteria. Antibiotic usage includes a course of a penicillin followed by a round of doxycycline or another antibiotic with similar action (such as erythromycin or azithromycin). Anti-nausea medications and a prescription renal diet are also included in the treatment protocol. Your dog will likely be hospitalized for roughly one week, receiving these intravenous (IV) treatments before being sent home on several oral medications, often including another week of antibiotics and liver-supporting medications. While hospitalized, a urinary catheter with a collecting bag will likely be placed in your pet to allow for proper collection and safe disposal of urine to prevent contamination to the veterinary clinic staff members. (Remember, Leptospirosis can infect humans too!)
Prognosis
The overall mortality rate of Leptospirosis infection in dogs is nearly 30%. However, the prognosis is usually good following a swift diagnosis and adequate treatment plan. However, even with proper treatment, some dogs may experience long-lasting chronic kidney disease and liver disease. Within 3-5 days of initiating treatment, your veterinarian should be better able to determine your dog’s individual prognostic outlook. If your dog’s clinical signs and bloodwork are improving, the prognosis is likely to be quite good. However, if no great improvements occur or if your dog’s status declines further, the prognosis is likely to be grave due to persistent liver damage and progressive kidney failure, leading to death or euthanasia.
Prevention
The Leptospirosis vaccine is one way to reduce your dog’s chance of developing the potentially deadly consequences of Lepto. It is an optional vaccine given to adult dogs or older puppies starting at 12 weeks of age. The initial inoculation is boostered once or twice (3-4 weeks after the initial vaccine) and then annually thereafter.
The Leptospirosis vaccine is optional for your dog (versus a core, or vitally recommended, vaccine) for two main reasons: 1) Depending on your specific area, your dog’s potential risk of contacting Lepto may be low. 2) In comparison to other inoculations, some forms of this specific vaccine may cause more vaccine reactions, leading to potential side effects such as pain or anaphylaxis. Therefore, the risk versus benefit of the Lepto vaccine must be carefully measured for each individual dog in regards to determining the appropriateness of vaccination. If you have any questions, your personal veterinarian will be happy to guide you through the pros versus cons of vaccination for your specific canine companion.
Keep in mind that the the current canine Leptospirosis vaccine is only protective against the specific canicola serovar. While this type of Leptospira interrogans is the most common serovar affecting dogs, keep in mind that your dog will not be 100% protected against acquiring other serovars of Leptospirosis. And unfortunately, up to 30% of dogs may not amount a sufficient immune response following vaccination to protect them from canicola infection. Major bummer! You, therefore, must also implement other protective measures such as proper rodent control and reducing your dog’s exposure to areas of potential Lepto contamination, such as around agricultural farms or in wildlife areas like the woods, particularly after heavy rains.
Click here to learn more about the Leptospirosis vaccine for dogs and other important vaccinations and preventative medicine for your adult dogs and puppies.
Risk to Humans and Other Dogs
As mentioned, Leptospirosis is a zoonotic disease, meaning that it can be passed to humans from animals (be they livestock, rodent, or dog). As in dogs, Lepto infection can lead to severe liver disease and kidney failure in humans as well, requiring prompt detection and treatment, including proper antibiotic usage and supportive care. Speak with your personal medical physician or public health center for advice on how to keep yourself safe from infection. Since we dog lovers enjoy spending time with our canine friends, one way to decrease your own risk of acquiring Leptospirosis is to prevent infection in your dog too. This starts with the canine Leptospirosis vaccine at your veterinarian’s discretion.
If one of your dogs unfortunately becomes infected with Leptospirosis, disinfect your household with bleach to kill L. interrogans bacteria shed by your dog. However, do not spray or flush puddles of urine or other areas contaminated by your infected dog to avoid aerosolizing the infectious agent and breathing it in or swallowing it. If you have other dogs in the household or if your dog was in contact with a neighbor’s dogs, these other exposed canines should be administered appropriate oral antibiotics by your vet for 14 days to be on the safe side.
– Maranda Elswick, DVM
If you suspect that you or your dog has been exposed to Leptospirosis, The Meowing Vet recommends that you contact your personal doctor and veterinarian, respectively. #OneHealth
