Question: My dog was recently diagnosed with Leptospirosis. What is this disease and where would my dog have been exposed to it? My dog never misses his annual vaccinations shouldn't’t they have protected him?
Answer: Leptospirosis is considered to be a reemerging disease of companion animals. This disease has been recognized for over one hundred years, and there has been an effective commercial vaccine available for approximately the last thirty years. Until recently, the incidence of the disease was relatively low. However, in the last eight to ten years the incidence of this disease has increased. In the last two to three years it has been diagnosed with increasing frequency country wide, particularly in Alabama, Georgia, Massachusetts, Michigan, New Jersey and New York.
This disease can cause an array of clinical signs. The severity of the disease can vary widely but it has the potential to be extremely severe, and in fact fatal. Symptoms are typical of kidney and/or liver disease, and can include, fever, loss of appetite, muscle pain, dehydration, vomiting, diarrhea and bleeding. Some dogs will have an increased water consumption and urine output while others may have a decreasing output of urine. Jaundice may occur, and the dog may be painful in the abdominal area or in the lower back. In extremely acute cases, a dog may suddenly go into shock and succumb.
The course of this disease can be chronic or extremely acute. Due in part to the fact that the symptoms in chronic cases can be vague as well as the fact that it has not been a common disease for many years, the potential for confusing the diagnosis with other diseases is possible.
Laboratory work is essential to establishing the diagnosis of Leptospirosis.. On a routine blood count and blood chemistry there are typically abnormalities that suggest kidney or liver disease. Diagnosing Leptospirosis definitively however, depends on demonstrating the organism in urine or in kidney or liver biopsy specimens. Antibody testing is also available, but early on in the course of the disease the results can be difficult to evaluate with accuracy. Your veterinarian and the testing laboratory can help guide you through the diagnostic challenge created by this disease.
Once Leptospirosis is diagnosed, treatment is undertaken with aggressive antibiotic therapy as well as supportive care. The specifics of these therapies are dictated by the magnitude and duration of the disease as well as what damage has been done to organ systems. Since Leptospirosis is infectious to humans, strict sanitary precautions should be taken when handling blood, urine or stool of infected animals. Also, infected dogs should be confined in such a way so as to avoid contact with other dogs as well as those areas that children would play in such as playgrounds, sandboxes, ponds or wading areas.
Understanding why this disease has reemerged requires some understanding of the organism itself as well as the manner in which it is transmitted.
Leptospirosis a bacteria of which there are seven species that are pathogenic. Among these species there are more than 200 pathogenic varieties (serovars), worldwide. Historically, in the United States, two varieties (canicola and icterohaemorrhagiae) were primarily responsible for the disease in dogs. The incidence of infection from these two has declined over the past thirty years most likely due in large measure to vaccination. The increase in cases most recently has been due primarily to the varieties pomona and grippotyphosa. Until recently no vaccine for these varieties was available, and vaccination for canicola and icterohaemorrhagiae does not protect dogs from pomona and grippotyphosa.
Leptospira varieties have what are termed maintainance hosts and incidental hosts. Maintenance hosts are those animal species which serve as a reservoir for the Leptospira organism, and in which transmission is very efficient. Incidental hosts include those species of animals that do not act as reservoirs, but that can be infected by the organism. The organism replicates in the kidneys of maintenance hosts and is shed in the urine. In warm damp environments the organism can survive for months in water or soil. Transmission can occur to the new host, either maintenance or incidental, by coming in contact with contaminated water, soil or the carcass of an infected animal. Given the fact that maintenance hosts for pomona and grippotyphosa include skunks, opossums, raccoons and small rodents it is easy to see how our dogs could readily be exposed to this organism when they swim or run in wooded areas or parks.
Prevention of this disease clearly is preferable to treating it, and there is now a vaccine that protects against all the common varieties of Leptospira. For those of us in areas, or traveling into areas where there have been outbreaks, vaccination should be a consideration. If you are unaware of the magnitude of the problem in your area, a call to your regular veterinarian or possibly your state veterinarian may be an appropriate step to take to asess your dogs level of risk.
Dr. Henry De Boer Jr. practices veterinary medicine at his Pioneer Valley Veterinary Hospital in western Massachusetts. An accomplished competitor in the sport of Schutzhund, his involvement with working dogs dates to the mid 1960's when he began training and handling hunting dogs. In 1984 he became involved with the sport of Schutzhund and has gradually risen to the level of national competitor. Known primarily as a motivational trainer, he also provides training assistance to others to help them achieve their training goals. His wide range of experience lends a unique understanding to the special veterinary problems of working canines and their handlers. Dr. De Boer provides specialized online veterinary services to working dogs and their owners on his innovative web site http://www.workingk-9vet.com Working K9 Veterinary Consultation Services.