What is Leptospirosis?

What is Leptospirosis?

Leptospirosis (often referred to “lepto” for short) is a zoonotic disease carried by spirochete bacteria.  The spirochete is shed primarily in the urine of infected animals and enters the body through cuts, abraded skin, water-softened skin, eyes and mucous membranes.

Lepto has hundreds of types, called serovars, with 4-5 particular serovars that are most common to cause illness in dogs.

Leptospirosis organisms survive in wet conditions and die in dry conditions.  Our plentiful rainy seasons in the Pacific Northwest are a prime breeding ground for Lepto organisms with all the puddles.  This is also why Leptospirosis is not a serious risk in all areas of the country – our transplants from Arizona or Texas often have not heard of/been vaccinated for Lepto.  (Hawaii is the other big Lepto area).

Who does Leptospirosis affect?

Lepto is a zoonotic disease, so can be transmitted between our pets to us.  Dogs are at risk for contracting and developing the disease due to their indoor/outdoor lifestyle.  We used to be concerned about this disease primarily with hunting/hiking dogs but over the past few years, local veterinary hospitals (including us) have been diagnosing Lepto infected dogs in suburban areas.

Leptospirosis can infect virtually any mammal.  Wild animals are the reservoirs for the Leptospirosis organism:  rats, raccoon, skunk, opossum, mouse, sea lions.  Cattle are also susceptible to Leptospirosis.

One particular risk factor for Leptospirosis is whether there are any “backyard” chickens around – anywhere you have chickens, you have rats because of the feed being spread around.  A Multnomah County study 2009-2010  has 14.5 to 29% of rats testing positive for Leptospirosis.

Human cases of Lepto are common in certain parts of the world.  It causes quite severe flu-like illness and can be fatal in severe cases.

Cats are NOT known to be susceptible to Leptospirosis – probably because they have evolved to eat the rodents that carry Lepto.

What does the disease do?

Once in the body, the bacteria causes internal organ damage, primarily to the kidneys and liver.  Dogs present for anorexia, vomiting, lethargy, and bloodwork usually reveals an indication of acute renal failure (90% of cases) though some serovars cause primarily liver failure.  We confirm infection via a Leptospirosis PCR test.

Is Leptospirosis treatable?

It is, but the patient will need intense hospitalization for the kidney failure and antibiotics.  The prognosis actually can be good if the kidney failure can be reversed, and the patient may have little to no long-term effects from it.

Is Leptospirosis preventable?

The vaccine for Lepto protects against the 4 most common serovars that cause illness in dogs.  It is given as a series of 2 boosters then yearly thereafter. In the vaccine controlled efficacy studies, the protection from the vaccine from these serovars range from 90-100%.  Importantly, though, the vaccine study reported nearly 100% control of shedding the bacteria in urine in vaccinated dogs, meaning it significantly reduces the likelihood of spreading the disease.

A vaccinated dog can still get infected from Leptospirosis that is a different serovar.

Is the Leptospirosis vaccine safe?

Historically, we did not vaccinate every dog with Leptospirosis because of the increased vaccine reaction rate with the previously available vaccine.  In addition, the “old” vaccine had a questionable efficacy rate and duration.  HOWEVER, the “new” Leptospirosis vaccine that we now have is much more purified and the systemic and local reaction rates have been no more than other vaccines.  We do not appreciate any more reaction in smaller dogs, either.

Because of the zoonotic risk and the prevalence of Leptospirosis in our area, Frontier moved the Leptospirosis vaccine into our “core” vaccines for dogs a few years ago.