In the last two years, we have seen an unusually high number of cases of the bacterial disease  “Leptospirosis” in the Canal Fulton area.  Conversations with other vets in Stark, Tusc., and Wayne county and recent journal articles are telling us that this is  not just a local problem, but a nationwide outbreak. 

We used to think of “lepto” as a disease that mostly would infect sporting or outdoor dogs because it is spread mostly by  wildlife and livestock. This current emerging epidemic, however,  has infected and, sadly,  in some cases killed even the most pampered of pooches. This sudden shift can be attributed theoretically to several factors, including an epidemic of lepto in wildlife, and the tendency of the veterinary profession to not vaccinate indoor dogs for this disease.  

Routinely, we ask our clients if they feel their dogs are at risk for lepto, ie: are they exposed to wildlife or livestock or do they spend any times in ponds or creeks?  Most clients  tell us “no” .  This current outbreak, though, forces us to rethink just what dogs are at risk for lepto.  “Wildlife” doesn’t have to mean a black bear or  10 point buck.  The cute little bunnies hopping around your yard, the amusing dog-teasing squirrels that visit your bird feeder,  the grass-nibbling groundhogs you see on every road side, and the opossums and raccoons that visit your yard when you are sleeping are the real source of the current outbreak.   Every drop of urine these creatures leaves behind is a potential source of lepto for your dog.   Therefore, unless your dog stays indoors all the time, is never on grass ever, the risk for exposure is definite. 

Since we now believe that any dog can be exposed to lepto and this recent outbreak is coming from an explosion of the disease in our common yard critters, why don’t we just vaccinate every pooch like we do for rabies?  Won’t vaccinating just prevent the disease in all dogs? Ay, there’s the rub.  The lepto vaccine is not as protective as the rabies vaccine because it is not really a vaccine at all.  The term vaccine describes an immunization against a virus that stimulates antibody production. Since lepto is a bacteria and not a virus, it is technically known as a “bacterin.”   As a general rule, bacterins do not provide as strong of disease-fighting immune response as vaccines, because bacteria are fought primarily by a different part of the immune system (the white blood cells) and not the chemical antibodies.  White blood cells don’t have “memory” like the antibodies do and cannot provide a protection before the agent actually enters the body.  Therefore, the immunity stimulated by bacterins is not as strong or as long-lasting as a vaccine against a virus. 

Another reason we don’t just lepto vaccinate every thing with fur is that the vaccine does not protect against every strain out there.  The older vaccines contained only two strains of the bacteria (known as “serovars” ); the new vaccines contain four.  There are over 200 known serovars of the disease and current science can only test for a paltry few of those. However, the vaccine may at least lessen the disease in many serovars, even if it cannot prevent them from setting up shop in some unfortunate dog’s body. 

Finally, the third and most important reason we don’t just set up a drive through window and lepto vaccinate every passing dog is that of all the vaccines we routinely give, the lepto vaccine has the highest vaccine allergic reaction rate.  This is simply because since the vaccine is actually a “bacterin” and does not produce as strong of a response as a viral vaccine, the manufacturers have to put more organisms in it to make it work.   Those organisms are covered with proteins that trigger anaphylaxis in about 5% of dogs. Usually this reaction is a simple case of hives and a swollen face that can be easily treated.  A very small group of dogs, however, can have a serious reaction that can be very quickly fatal.    This is similar to the risk every person has when given an injection of penicillin. 

The real question, of course, is the vaccine worth the risk?  Lepto is indeed a very serious disease that is difficult to diagnose in the early stages and potentially fatal.  Even if the dog survives the early phase of it which is usually (but now always)  characterized by vomiting, muscular pain, loss of appetite, and increased water consumption,  the poor dog may go into a potentially fatal phase of  kidney and/or liver failure and a  blood clotting disorder.  Though we can treat the disease with a long course of multiple antibiotics, that may not prevent the dog from developing the more serious signs.  Also, there is a human health concern as lepto is a “zoonotic” disease--  animals can infect people, so these dogs become a potential source of disease for their human companions. 

The question is no longer “Will my dog be exposed to Lepto?”  If your dog’s paws ever touch the natural ground the answer is “yes.” Your dog will be exposed.  The real question is now : “Should I vaccinate my dog?” Despite the imperfections of the lepto vaccine, we believe the seriousness of the disease and this current outbreak does indeed warrant vaccinating most dogs. Of course, we cannot know in advance which animals  may react or we wouldn’t give them the injection in the first place.  Therefore, it is up to each individual owner to weigh the pros and cons-- the rewards vs the risks-- in deciding whether or not you should vaccinate your dog against this life-threatening zoonotic disease.  We will do everything we can to lessen the risk of reaction by using only the highest quality vaccines (Merial or Pfizer), only giving the vaccine to dogs over 6 months of age, and vaccinating only for lepto on the day of the vaccine.  We do not combine the lepto vaccine with any other .  If your dog has ever had an allergic reaction to any vaccine, or is a breed (like a dachshund) that has a high reaction rate, we will not recommend vaccinating for lepto.  If any litter mate or parent of your dog has ever had a reaction to a lepto vaccine, we will not recommend vaccinating for lepto.  

To keep your dog protected, lepto vaccines have to be given at least annually.  Some dogs (such as sporting dogs) should get this vaccine every 6 months.   The very first time the dog is given a lepto vaccine, it has to be repeated in 1 month.   We recommend when you schedule your dog for a lepto vaccine, choose an early time slot,  so if your dog does have a reaction we will be there to help.    

Melanie Butera, DVM    10/12/2010