Canine Leptospirosis: Symptoms, Diagnosis, and Treatment

Leptospirosis is an infectious disease caused by a bacterium (Leptospira interrogans) that can affect many domestic mammals, including dogs, and even humans.

That's why it's important to know how it presents, its early symptoms, and what we should do to treat it. At Soyunperro we'll show you everything you need to know about this disease.

What Is Canine Leptospirosis?

Canine leptospirosis is an infectious disease of very high medical importance in dogs that can also be transmitted to humans (zoonosis), which is why it's important to take every possible precaution to prevent transmission.

As mentioned, the bacterium responsible for this condition is normally Leptospira (hence the name). The one affecting humans and animals is: Leptospira interrogans. It's of great health importance due to its ability to cause miscarriages in humans.

Reservoirs (hosts) for this bacterium include small mammals, ruminants, carnivores, and pigs.

How Is Leptospirosis Transmitted?

It has two main transmission routes:

1. Direct: through the urine of infected dogs, via the oro-nasal route (through the nose), the conjunctival route (eyes), and venereal transmission (mating).
2. Indirect: through water contaminated with Leptospira and through wounds.

After entering through any of these routes, it passes into the blood (over about 8 days) and then spreads to organs such as the liver, kidney, eyes… This triggers a strong humoral response (antibodies) from our pet to fight the disease. If untreated, it can progressively damage our pet's organs to levels that are hard to treat.

Main Symptoms of Canine Leptospirosis

Generally, the dog will show clear physical deterioration. In addition, if it shows symptoms related to urination, the kidneys may be affected.

The most common are:

• Fever and tremors
• Loss of appetite
• Dehydration
• Vomiting or diarrhea (sometimes with blood present).
• Dark-colored urine
• Jaundice (yellow mucous membranes) in more advanced cases

With this disease, time is of the essence, and the sooner treatment begins, the better the dog's chances of surviving leptospirosis and recovering. If you detect these signs in your furry friend, you need to see the vet urgently.

Diagnosis of Leptospirosis

Once at the vet clinic, the specialist will take a full history and perform a complete physical exam, taking into account every symptom we've described. Fever, jaundice, dehydration, and possible tachycardia may be observed.

Bloodwork may also be run, which can show an increase in white blood cell count. This is normal, since these are the immune system's own defenses acting against the bacteria. If there's liver damage, elevated liver enzymes may be observed, along with other signs that an organ is failing.

The vet will need to distinguish it from other infectious diseases, since several of them can show similar symptoms, and it's sometimes not easy to diagnose. A urinalysis can be useful for detecting changes in urine pH as well as white blood cells.

How Is Canine Leptospirosis Treated?

To fight canine leptospirosis, a pharmacological treatment with broad-spectrum antibiotics is needed, combined with symptomatic treatment if there's any other treatable symptom.

If there's liver and kidney damage, those symptoms will also need to be treated, for example with liver protectants and a kidney and/or liver diet, depending on symptoms.

Either way, the vet is the only person who can advise you on a case-by-case basis and best knows what's best for your furry friend, taking its health condition into account.

Can Leptospirosis Be Prevented?

The best remedy against canine leptospirosis is always prevention. For this, it's important to vaccinate the dog, which will significantly reduce the risk of it catching this disease.

The first two doses are given as puppies (polyvalent vaccine); from there, annual vaccination is recommended. In domestic animals, vaccination is effective at preventing the disease, but doesn't completely protect against infection.

The immunity our dog develops if it catches the infection can last a lifetime, but is specific only to the infecting serotype (bacterial type).

Is Canine Leptospirosis Contagious to Humans?

Leptospirosis can be transmitted to humans. Transmission occurs when a person comes into contact with water, food, or urine contaminated with bacteria of the genus Leptospira, species interrogans.

That's why special care is needed with children living with dogs. It can also be acquired through the ground, if the surface has been infected and there's a habit of walking barefoot.