Recently there has been a lot of interest generated in this area about a disease known as leptospirosis. Many area veterinary clinics are strongly recommending vaccination of all dogs against "lepto" and many area boarding facilities and doggie day cares have begun recommending the same. So what is this disease and should you get your dog vaccinated against yet another thing?
Leptospira is a bacterium that can cause severe illness in a dog that contracts it. Most commonly it infects the liver and the kidneys and causes lethargy, vomiting, diarrhea, yellow skin, and shock and alarm in veterinarians when they look at a patient’s bloodwork and see extreme abnormalities. A more dramatic form of the disease presents as sudden, overwhelming shock and collapse. These patients are difficult to save. A sneakier version of the disease causes no overt sickness, but may result in a patient drinking more and urinating more for no obvious reason. These patients can spread the disease to others even though they are not ill themselves. Cats seem to be very resistant to the disease.
Because the bacteria like to live in the kidneys they can migrate into the urine and are passed into the environment wherever an infected animal urinates. When exposed to heat and dry air the bacteria die fairly quickly, but if they land in a place that is cool and moist, like a puddle or pond, they can survive for a long time outside the body. The next host becomes infected when it drinks from that puddle or possibly licks its feet after walking through a contaminated zone. Many types of wildlife are known to carry leptospira, and rats and mice in particular are notorious contaminators.
It is important to note that humans can also get sick from leptospira. A sick pet will expose the human members of the family to the same potential problems that dogs present with. For this reason it is a very good idea to get a diagnosis confirmed when the disease is suspected and to take precautions to prevent exposure to possibly infected urine from a canine patient.
Until recently I considered leptospirosis to be a problem that was found primarily in geographically distant places. Many common dog vaccines have a portion that protects against leptospira, but that portion is known to cause a much higher rate of adverse vaccine reactions. It didn’t make sense to risk a reaction to a part of the vaccine that is protecting against something that we will never see here. This year we have learned that leptospirosis is no longer just other people’s problem. At our clinic alone we have had several confirmed cases and several more highly suspected cases. Many of these dogs were life-threateningly ill. Our cool, wet summer last year may have played a part in creating more favorable conditions for the spread of the disease.
It would be logical to think that the dogs that are really at risk are outdoor-types. In reality we have had an equal number of pampered indoor only dogs whose feet rarely touch the ground. I suspect the reason is that mice are very good at getting into indoor spaces, and no dog, no matter how delicate, will pass up an opportunity to sniff and lick up mouse urine when a chance presents itself.
So, should you get your dog vaccinated for leptospira? I would say yes. The possibility that a dog will have an annoying but not dangerous vaccine reaction is far outweighed by the risk to both the pet and its family if the disease is contracted.
Of course there is a catch. Leptospira actually comes in several different serovars, which are like different species. Clinically they all cause the same problems, but no vaccine protects against all the serovars. Currently available vaccines protect against four of them, but there are two common serovars that they do not protect against. Of the cases we have seen, some would have been protected by vaccination and some would not. Even so, partial protection is better than no protection.