Leptospirosis is an infection of bacterial spirochetes, which dogs acquire when subspecies of the Leptospira interrogans penetrate the skin and spread through the body by way of the bloodstream. Two of of the most commonly seen members of this subspecies are the L. grippotyphosa and L. Pomona bacteria. Spirochetes are spiral, or corkscrew-shaped bacteria which infiltrate the system by burrowing into the skin. Leptospires spread throughout the entire body, reproducing in the liver, kidneys, central nervous system, eyes, and reproductive system. Soon after initial infection, fever and bacterial infection of the blood develop, but these symptoms soon resolve with the reactive increase of antibodies, which clear the spirochetes from most of the system. The extent to which this bacteria affects the organs will depend on your dog’s immune system and its ability to eradicate the infection fully. Even then, Leptospira spirochetes can remain in the kidneys, reproducing there and infecting the urine. Infection of the liver or kidneys can be fatal for animals if the infection progresses, causing severe damage to these organs. Younger animals with less developed immune systems are at the highest risk for severe complications. The Leptospira spirochete bacteria is zoonotic, meaning that it can be transmitted to humans and other animals. Children are most at risk of acquiring the bacteria from an infected pet.
Symptoms and Types
- Sudden fever and illness
- Sore muscles, reluctance to move
- Stiffness in muscles, legs, stiff gait
- Lack of appetite
- Increased thirst and urination, may be indicative of chronic renal (kidney) failure, progressing to inability to urinate
- Rapid dehydration
- Vomiting, possibly with blood
- Diarrhea - with or without blood in stool
- Bloody vaginal discharge
- Dark red speckled gums (petechiae)
- Yellow skin and/or whites of eyes – anemic symptoms
- Spontaneous cough
- Difficulty breathing, fast breathing, irregular pulse
- Runny nose
- Swelling of the mucous membrane
- Mild swelling of the lymph nodes
The Leptospira spirochete infection mainly occurs in subtropical, tropical, and wet environments. Leptospira spirochetes are more prevalent in marshy/muddy areas which have stagnant surface water and are frequented by wildlife. Heavily irrigated pastures are also common sources of infection. The infection rate for domestic pets has been increasing in the U.S. And Canada, with infections occurring most commonly in the fall season. Dogs will typically come into contact with the leptospira bacteria in infected water, soil, or mud, while swimming, passing through, or drinking contaminated water, or from coming into contact with urine from an infected animal. This last method of contact might take place in the wild. Hunting and sporting dogs, dogs that live near wooded areas, and dogs that live on or near farms are at an increased risk of acuiring this bacteria. Also at increased risk are dogs that have spent time in a kennel.
Because leptospirosis is a zoonotic disease, your veterinarian will be especially cautious when handling your pet, and will strongly advise you to do the same. Protective latex gloves must be worn at all times, and all body fluids will be treated as a biologically hazardous material. Urine, semen, post-abortion discharge, vomit, and any fluid that leaves the body will need to be handled with extreme caution. You will need to give a thorough history of your dog's health, including a background history of symptoms, recent activities, and possible incidents that might have precipitated this condition. The history you provide may give your veterinarian clues as to what stage of infection your dog is experiencing, and which organs are being most affected. Your veterinarian will order a chemical blood profile, a complete blood count, a urinalysis, an electrolyte panel, and a fluorescent antibody urine test. Urine and blood cultures will also be ordered for examining the prevalence of the bacteria. A microscopic agglutination test, or titer test, will also be performed to measure the body's immune response to the infection, by measuring the presence of antibodies in the bloodstream. This will help to definitively identify leptospira spirochetes and the level of systemic infection.
Dogs with acute severe disease should be hospitalized. Fluid therapy will be the primary treatment, in order to reverse any effects of dehydration. If your dog has been vomiting, an anti-vomiting drug, called an antiemetic, may be administered, and a gastric tube can be used to nourish your dog if its inability to eat or keep food down continues. A blood transfusion may also be necessary if your dog has been severely hemorrhaging. Antibiotics will be prescribed by your veterinarian, with the type of antibiotic dependent on the stage of infection. Penicillins can be used for initial infections, but they are not effective for eliminating the bacteria once it has reached the carrier stage. Tetracyclines, fluoroquinolones, or similar antibiotics will be prescribed for this stage, since they are better distributed into the bone tissue. Antibiotics will be prescribed for a course of at least four weeks. Some antibiotics can have side effects that appear serious, especially those drugs that go deeper into the system to eliminate infection. Be sure to read all of the warnings that come with the prescription, and talk to your veterinarian about the indications you will need to watch for. Prognosis is generally positive, barring severe organ damage.
Living and Management
A vaccination for the prevention of the leptospirosis infection is available in some areas. Your veterinarian can advise you on the availability and usefulness of this vaccine. Make sure to inspect kennels before placing your dog in one – the kennel should be kept very clean, and should be free of rodents (look for rodent droppings). Urine from an infected animal should not come into contact with any other animals, or people. Activity should be restricted to cage rest while your dog recovers from the physical trauma of this infection. Leptospirosis is a zoonotic disease, transmissible to humans, and other animals via urine, semen, and post-birth or post-abortion discharge. While your dog is in the process of being treated, you will need to keep it isolated from children and other pets, and you will need to wear protective latex gloves when handling your dog in any way, or when handling fluid or waste products from your dog. Areas where your dog has urinated, vomited, or has possibly left any other type of fluid should be cleaned and disinfected thoroughly with iodine-based disinfectants or bleach solutions. Gloves should be worn during the cleaning process and disposed of properly after. Finally, if you do have other pets or children in the home, they may have been infected with the leptospira bacteria and are not yet showing symptoms. It may be worthwhile to have them (and yourself) tested for the presence of the bacteria. And, it is important to keep in mind that leptospires may continue to be shed through the urine for several weeks after treatment and apparent recovery from the infection. Appropriate handling practices will be the best prevention of the spread of infection, or of reinfection.