Leptospirosis: A Disease for people and animals

“Why should I vaccinate my dog against Leptospirosis?” This is a question that is asked in veterinary exam rooms across the country. Conscientious dog owners do not want to over-vaccinate their dogs and above all, they do not want to cause their pet any harm from vaccine side effects. Moreover, some owners are advised by their breeders to avoid the vaccine. How do you make the right decision?

Leptospirosis is a zoonotic disease- a disease that can be passed between animals and people. It is spread by spirochete (spiral-shaped) bacteria in the urine of infected rodents, wildlife, and pets. There are more than 200 different strains of leptospirosis and certain strains appear to prefer certain hosts, like dogs, pigs, raccoons or even rats.

The Leptospira organisms enter the body through mucous membranes or through abrasions on the skin. People and animals can become infected from direct exposure to infected urine, but also through a contaminated environment, such as water or damp soil.

A veterinary gastroenterologist communicated the following story to me about this devastating disease. A new veterinary school graduate honeymooning in Hawaii went swimming in a volcanic lake. When he got home he had a fever, flu-like symptoms, severely bloodshot eyes. The doctors could not diagnose the cause of his illness until he died and was autopsied. They isolated the Leptospira bacteria. The most likely explanation for his death was that wild animals had urinated in the still volcanic lake. The organisms had infected him through his mouth and eyes or possibly a scratch on his skin.

More recently the popularity of challenging races through muddy fields and woods with obstacles has increased the spread of Leptospirosis to people. The organism is in the mud and is splashed onto the mucous membranes of the eyes mouth and nose of the runners

People and pets are exposed to Lepto while camping or participating in outdoor recreational activities. Drinking or swimming in water that is infected with Lepto is the most common exposure, but wet soil can be contaminated as well. A city environment will not always provide protection against this serious disease. Rats and raccoons are prevalent in the urban environment and their urine is in puddles and city fountains and ponds.

The signs of Leptospirosis can mimic many other diseases and illnesses. The first signs in dogs are often depression, loss of appetite, vomiting, weakness, and generalized pain. Affected dogs may also drink water and urinate excessively and have swollen, red, and painful eyes. Because these signs are common to other diseases and non-specific, owners may try to treat their pets at home for such problems as an upset stomach or arthritis.

This “wait and see” response delays proper diagnosis and treatment for the dog, as well as increasing the owner’s exposure to the disease. If caught early, treatment is usually effective and the survival rate is good. However, time is of the essence. A mere three or four-day delay can lead to irreversible kidney failure.

Vaccines are available but many pet owners have either experienced or heard about adverse reactions associated with these vaccines. In the past, Leptospirosis vaccines were generally created using the whole bacterial organism. In many cases, when a whole bacterium is used, the likelihood of a “vaccine reaction” increases. Thankfully, newer vaccines have been developed that reduce this possibility by using specific Leptospirosis proteins instead of the whole organism.

A study reviewing vaccine reactions in more than one million dogs vaccinated found that reactions occur about 13 times for every 10,000 vaccines given. More importantly, the Lepto vaccine was no more likely to cause a reaction than any other vaccine.

So, if the vaccine appears to be safe and the disease deadly, shouldn’t all dog owners vaccinate their pets?

At present, vaccines are available that protect against four of the common strains infecting dogs. In addition, the vaccine will prevent clinical disease, but may not stop the pet from shedding bacteria in his urine. This makes the pet a threat to other animals, especially those who are not vaccinated. And, as mentioned above, humans are at risk as well.

Dr. Richard Goldstein, who is a respected lecturer and research veterinarian with Animal Medical Center in New York City states, “If a veterinarian and owner have not vaccinated the dog against this disease then we have failed the dog.” He has personally worked with a seeing eye dog kennel in New York that had many of their dogs affected by the disease. Fighting for the lives of those assistance dogs as well as his own research convinced him that dogs should be vaccinated.

Worldwide, Leptospirosis is the most widespread zoonotic disease. Cases occur routinely in tropical countries, but increases have been seen in Europe and North America as well. Floods and hurricanes are instrumental in spreading this illness and coordinated efforts to rescue and re-home pets from these disasters might actually transplant leptospirosis into new areas.

Protecting your pet from Leptospirosis can be achieved. Use your veterinarian as a resource to help assess your pet’s risk factors as well as the benefits and hazards of vaccination. Other important steps that might minimize your pet’s exposure to this disease include removing animal pests, such as rodents and draining areas of standing water. Your dog’s health and your own will be much better protected if you take precautions to prevent the disease.