What is leptospirosis?
Leptospirosis is a disease caused by bacteria of the genus Leptospirosa which can be found in water, food, soil and other substances contaminated by the urine of rats and other mammals that carry the bacteria. It's one of the most common zoonoses, an infection or disease that is transmissible from animals to humans and vice-versa. Disease transmission occurs when the bacteria present in the contaminated urine or infected substances come into contact with mucous membranes (in the mouth, eyes or nose) or skin lesions.
What animals can be infected?
Rodents, foxes, skunks, raccoons, ruminants, swine and horses can all be infected with leptospirosis. But, due to their proximity to people and contaminated environments, cases of leptospirosis in dogs are the most disturbing. Contrary to common belief, it's not only large dogs with access to lakes and marshes who are at risk. Recent data indicate that an increasing number of small dogs and outside cats are also becoming infected. Felines tend to be asymptomatic and get infected when hunting small rodents, which are among the most important hosts of leptospirosis.
What are the symptoms and consequences?
Leptospires multiply rapidly in the blood of an infected dog, colonizing organs such as the liver, kidneys, lungs, eyes and central nervous system. The average incubation period is approximately 1 week but can vary between 2 and 30 days. An infected animal may present with bloody urine, weakness, loss of appetite, vomiting, fever, increased thirst and urination, jaundice, conjunctivitis, severe vasculitis or hemorrhagic gastroenteritis.
How can we confirm it is leptospirosis?
It's important to keep a detailed description of all symptoms (as their manifestation, intensity and duration can vary from one animal to another) and have your pet undergo blood testing immediately following the first signs of infection. All dogs who have a fever and liver- or kidney-related problems should be tested for leptospirosis. Your veterinarian will run comprehensive blood testing and may use medical imaging to check for damage to organs frequently targeted by leptospirosis. A serological test to detect the presence of antibodies will help confirm diagnosis.
Does treatment for leptospirosis exist?
The only existing treatment to eliminate bacteria is a course of antibiotics administered for several weeks at the onset of illness. Nevertheless, because leptospirosis is a multi-system disease, measures to stabilize kidney, respiratory and liver functions are usually also prescribed.
Acute renal impairment, present in almost 90% of leptospirosis cases, is the most common consequence of the disease. Although acute renal failure can lead to death within 5 to 10 days, an average of 80% of dogs will survive and less than 20% will have chronic kidney disease. When leptospirosis attacks the liver or lungs, the long-term prognosis is less promising. If the animal does survive, there is a high risk of it becoming a chronic carrier of leptospirosis and shedding the disease over the long term.
Can we prevent leptospirosis?
For dogs, yearly vaccination, which has had a good track record over the past years, is the most effective preventive measure. Unfortunately, a vaccine does not currently exist for cats. As leptospirosis is an environmental disease which is more prevalent in the autumn it's essential to limit risk of contamination with precautionary measures, including careful personal hygiene and stopping your dog from drinking or walking in sources of water to which wildlife and rodents have access.
In conclusion, remember that this disease is much easier to prevent (with your veterinarian's help) than treat (with your doctor's help)!