This article may be seen in its original form by purchasing the back issue from which it came.

by Cheryl Giebel

Classie

Leptospirosis bacteria

Leptospirosis (lep-toe-spir-o-sis): You may have never heard this word, or you may have heard the name, but don’t really know what the disease is. Leptospirosis is an under diagnosed, silent disease that has been around for possibly 100 years and can be found all over the world. It is a thin, flexible, corkscrew or spiral-shaped bacteria called a spirochete. Lyme disease is a similar spirochete. I hope that by sharing the story of our 8-year-old Greyhound’s experience with leptospirosis, you will walk away better informed about a serious bacterial disease that can sneak up on your Greyhound, do a lot of severe internal damage, and possibly be fatal.

Cause

The cause of leptospirosis can be from several different animal or human sources. The main source of contracting these spiral-shaped bacteria is through contaminated urine. It may be possible to spread the bacteria through contaminated saliva as well. Urine contamination can be from any number of mammals, such as raccoon, squirrel, opossum, skunk, deer, fox and even cows, pigs, horses, or sheep. The most common culprits are rodents, such as mice, rats, and voles. Dog to dog transmission is rare.(1)  The most prevalent mode of transmission is exposure to stagnant or slow-moving water that has been contaminated by an infected animal. The organism may survive up to six months in water. That is why the disease is more prevalent in spring, autumn, and in times of flooding. Exposure is also more common in tropical areas of the world. The infected urine or contaminated water can enter the body through mucous membranes (eyes, mouth, or nose) or skin abrasions. It can be transmitted through contact with infected soil and grass as well as contaminated food or bedding. It is even possible to contract the disease from infected meat or the carcass of an infected animal. Affected canines can be any age, sex, or breed, but those mainly from suburban or rural environments seem to be at higher risk. The presence of raccoons and squirrels in urban areas pose a threat as well. We were never able to find out how Classie was exposed, but we do have several acres fenced in for our dogs to run and raccoons, skunks, and deer frequent our yard. Additionally, we had much flooding in our part of Wisconsin last spring.

Worldwide there are over 200 different strains or serovars of leptospirosis, thereby making it difficult to diagnose. At least eight are of most importance for dogs.(2) The strains most important to us in the United States are L. icterohaemorrhagiae, L. canicola, L. grippotyphosa, L. hardjo, L. pomona, L. autumnalis, and L. bratislavia. According to a scientific report, “The incidence of disease attributed to serovars canicola and icterohaemorrhagiae has decreased, whereas the number of reports of canine leptospirosis associated with serologic evidence of infection with other serovars, particularly grippotyphosa, pomona, and bratislavia, has increased.”(3)  Humans can also get the disease, which makes it one of many zoönotic (contagious to humans) diseases. They can then give it to animals. According to CG “House Calls” author and veterinarian Jim Bader, “The human has to actively have leptospirosis and be excreting it in the urine.” This contaminated human urine must then be deposited where animals would have access to it. In humans, leptospirosis is called Weil’s disease and usually results from living in a tropical climate, avid swimming, or is an occupational hazard such as farming. In 1995, the Center for Disease Control removed leptospirosis from the list of nationally notifiable diseases.

Signs/Symptoms

The incubation period is approximately five to 14 days. Animal and human signs or symptoms are very similar. The leptospires circulate in the blood and then enter many tissues where they replicate. The spectrum of animal symptoms may include fever, weakness, stiffness, loss of appetite, increased thirst, and muscle pain in the beginning stages. You may notice a change in the color of your dog’s urine along with frequent urination. More severe manifestations include vomiting, diarrhea, jaundice, red eyes, bright red or bleeding gums, and mouth ulcers, which may lead to dehydration, progressing to kidney (renal) or liver failure. You may notice blood in the urine or feces in the later stages of the infection. If left untreated, leptospirosis may cause death. This is by no means a complete list of signs, but will hopefully give you enough information to seek veterinary help quickly if you see any of these symptoms.

Classie presented with the following signs that I did not pick up on immediately, even though I have my degree as a veterinary technician: lethargy, loss of appetite, bright red gums, and vomiting. She is one of those Greyhounds that stresses easily with change and her signs began on the first day of a camping trip in June of 1999. A change in your dog’s personality may be a sign as well. Classie normally has a very energetic personality. That day she was acting quite the opposite. It wasn’t until the third day, and her second time vomiting, that I sought veterinary help. Her temperature was not elevated, but blood work revealed that she was going into kidney failure. She also had bright red gums, which I did not know was a sign until after the diagnosis weeks later and subsequently researching this disease. Clinical signs, which your veterinarian will see from a blood sample, are abnormal kidney values and possibly abnormal liver values (see diagnosis section). The kidney failure, along with the outward signals mentioned above, should be enough evidence to begin treatment immediately. Immediate treatment is absolutely essential for a favorable outcome.

Treatment

One of the most important things to remember about leptospirosis is that treatment must be started immediately, even without a diagnosis, because lab results can take several weeks! As acute renal failure is the most common clinical syndrome observed in dogs with leptospirosis, standard therapy for acute renal failure is essential.(4) It is crucial that intravenous antibiotics, such as amoxicillin, ampicillin, or penicillin be administered immediately to eliminate circulating leptospires. Use of penicillins early in the course of disease decreases the extent of organ damage and hastens recovery.(5) Antibiotic administration can shorten the duration of the illness and urine shedding of the organism.

Intravenous fluids must also be started to counteract dehydration and loss of appetite while monitoring urine output. Aggressive fluid therapy in combination with ampicillin or amoxicillin resulted in a good survival rate, and hospitalization times ranged from three to nine days. (6) Classie was in the hospital on IV fluids along with ampicillin and another antibiotic (Baytril®) for five days. She didn’t even begin eating until the fourth day at the hospital, which was actually her seventh day without food. For nutritional support, she was given a prescription canned food diet that was very low in protein specifically for an animal with acute kidney failure (K/D or U/D). Then after her release from the hospital, she was put on a similar dry food diet for about two months. She lost about seven pounds over the one-week period. An oral antibiotic called doxycycline is recommended once the dog can keep food down, because this drug may induce nausea and vomiting when initiating therapy. It should be continued for at least two weeks and some veterinarians recommend up to eight weeks to clear the bacteria from the kidneys. The usual dosage is 5mg/kg of body weight twice a day. She was started on the oral doxycycline (100mg four times a day) the first day of her release and continued that treatment for eight weeks on recommendations previously used at the University of Wisconsin Veterinary Teaching Hospital. Dr. Rance K. Sellon states, “Early suspicion of leptospirosis and implementation of therapy is critical to successful treatment of these patients. The prognosis, for patients with renal failure, is guarded and patients may either recover completely, recover with diminished renal function, or may die of the infection.”(4) It is my understanding that if not treated properly initially, animals may have a reoccurrence of symptoms at a later time. Without Dr. Melissa Greenwood’s excellent veterinary care and treatment, the disease could have killed Classie.

Diagnosis

The diagnosis is difficult and involves a combination of procedures and tests. To begin, a complete blood panel was done. This may show white blood cell counts to be elevated and platelet counts to be decreased. The initial blood values for kidney and liver function will give your veterinarian indications of leptospirosis if your pet was in otherwise good health. When the liver is affected, there will be an increase in the liver enzymes. The bilirubin and/or urobilinogen may be elevated if there is liver damage. Classie’s blood urea nitrogen (BUN) level was high. From an earlier article in Celebrating Greyhounds, Fall 2000, Patricia Gail Burnham states, “…an animal has to have already lost 75 percent of its kidney function before the BUN will rise on a blood test. This means that a good BUN level does not mean that a dog has good kidney function. It just means that he is not down to his last 25 percent of kidney function yet.” Classie’s initial BUN level was 62.8, and the normal range is 6.0 – 27.0. Her creatinine level was also elevated again indicating kidney failure. Classie’s level was 6.26, and the normal range is 0.50 – 1.80. A creatinine value greater than 4.0 mg/dl and BUN value greater than 100 mg/dl were associated with death.(7) Creatinine and blood urea nitrogen are both waste products excreted by the kidneys so their levels go up in the presence of kidney diseases. Phosphorus levels will also rise when there is kidney damage. Classie’s level was 10.84 and the normal range is 2.50 – 6.80. Two days later, her phosphorus level was in the normal range, but her BUN and creatinine were still quite elevated. By the sixth day of hospitalization, her BUN was normal and her creatinine was almost in the normal range. Approximately, two weeks later her BUN was down to 9.0. Her creatinine was 1.40 and her phosphorus was 3.10. All were within the normal ranges. It is possible, however, for these kidney levels to take several months to improve.

Kidney failure is indicative of other diseases as well. Classie was initially tested for Lyme and ehrlichia also. The results from the Lyme and ehrlichia tests took six days. The Lyme results suggested previous vaccination against the disease, but no evidence of natural exposure. The ehrlichia result was negative. It took more than a week to get her first leptospirosis titers (six titers), and they were all reported at a very low 1:100 level, or not indicative of exposure. It is suggested to repeat the titers anywhere from 10 – 20 days to four weeks after possible exposure. The negative antibody titers can be explained due to a seven – nine day period required before antibodies are produced against the leptospires.(6) The second blood sample for titers was taken approximately three weeks after Classie’s illness began. The results were not reported back for another week. So you can see why it is more important to start treatment immediately, if there is any suspicion of this disease.

Seven strains were tested for, and two strains showed high enough titers to be suggestive of exposure to the bacteria. However, a low titer does not necessarily rule out a diagnosis. Classie showed a low titer for L. canicola for which she was vaccinated. Her other, higher titers were L. grippotyphosa (1:400), which is now included in the new Fort Dodge vaccine, and L. bratislavia, which has no vaccine at present. The L. bratislavia strain was her highest titer at a value of 1:800. A titer value of 1:800 or higher is supportive of a positive diagnosis, especially if it is against a serovar for which there is no vaccine. According to Carole A. Bolin’s article, “…the infecting serovar is assumed to be the serovar to which the animal develops the highest titer.”(1) The titer during acute illness should increase four-fold when repeated during convalescence. Although single titers are never diagnostic of current infection, titers 1:300 or greater are suggestive and titers 1:1,000 or greater are highly indicative of leptospirosis.(8) It has been suggested that previous infection or vaccination should produce a titer less than 1:300 but that titers from vaccinations can reach 1:1,250.6

Serum leptospiral antibody titers are determined using specialized diagnostic testing, such as the microscopic agglutination test (MAT), or the ELISA test. Urine can also be examined via darkfield microscopy and fluorescent antibody staining for leptospires that are usually present approximately four to ten days after the onset of clinical signs. An outside laboratory must perform the MAT, ELISA, darkfield microscopy, and fluorescent antibody staining. These tests are labor intensive, thereby increasing the time and cost of finding a diagnosis. The antibody titers are somewhat expensive to run, and negative titers initially may cause a veterinarian to dismiss the possible diagnosis and neglect to send in second titers two to four weeks later. Some dog owners may elect not to have the tests run once their dog has returned to a healthy state, however, the JAAHA article states, “Establishing a diagnosis is important, since dogs can serve as disease reservoirs and pose potential zoönotic risks.”(6) This has significance in the fact that there may be many dogs out there which have been infected with leptospirosis, but have never been diagnosed. New diagnostic tests are continually being researched. Your veterinarian can contact the National Animal Disease Center in Ames, Iowa for more information on diagnostic testing.

Recovery

Classie’s recovery was speedy. She regained her weight over the two months following her hospital stay. We continued to check her blood and urine values to make sure there was no permanent kidney damage. Urinalysis may show a low specific gravity initially (normal range is 1.007 – 1.022). This is the most important urine test value to make sure the dog is still able to concentrate its urine. All her blood and urine values were still completely normal two months later. Some are not so lucky and may end up with permanent damage to the kidney or liver. Some may contract the disease, but be asymptomatic; others may not survive their encounter with leptospirosis at all. Recovery is associated with improvement in the patient’s attitude, appetite, and clinical blood and urine values. Thankfully, Classie recovered completely and is very healthy to this day.

Factors which lean toward a favorable outcome include:

– Short time from symptoms to administration of ampicillin

– Administration of doxycycline

– Absence of acute renal failure

– Absence of jaundice

– Young age of the dog

– Production of urine on presentation

– Infection by the serovars L. canicola or L. pomona (L. icterohaemorrhagiae and L. grippotyphosa infections are usually more severe)

– Return of appetite

Carrier/Shedder States

After recovery there is still the question of the carrier/shedder states to consider. Some dogs go on to a chronic or progressive type of kidney failure long after the illness has passed. They become “carriers” and shed bacteria in their urine for as long as a year.(10) There are several different suggestions for the length of doxycycline use (the second phase of treatment) and its effectiveness in reducing or eradicating the carrier/shedder state. It is generally recommended to continue doxycycline use for a minimum of two weeks up to a maximum of eight weeks to completely eliminate the organisms from the kidneys. This is one of the few antibiotics that kill leptospira in the kidney thereby preventing shedding of the organisms in the urine. Again, Dr. Bolin states, “Appearance of circulating antibodies coincides with the clearance of leptospires from blood and most organs. Leptospires can remain in the kidney and may be shed in the urine for a few weeks to many months after infection.”(1) Shedding of the organisms in the urine can be intermittent. Recovered dogs excrete organisms in urine intermittently for months after infection and in surviving reservoir hosts, renal colonization will be long term, with shedding in urine for months to years.(2)

This shedding may pose an infectious risk to humans and other animals. Wildlife, domestic animals, and livestock can continue to harbor and shed organisms without clinical signs. These hosts maintain serovars as a potential source of infection and illness. Prolonged shedding of leptospires from the host is responsible for the persistence of leptospires in the environment.(11) It has been estimated that 30 percent of the canine population develops some form of leptospirosis.(12) In a 2000 investigation of antibody titers in 30 healthy normal dogs, 16 had a positive titer and nine had titers greater than or equal to 1:800. All of the titers but one were against serovars that are not included in vaccines available. You may wish to consider testing your dogs for antibody titers even if they are healthy because other dogs in the household may serve as asymptomatic carriers. According to Christy Shoup, a veterinary student at Cornell University, “If a dog is properly treated with antibiotics, he or she is no longer at risk for spreading disease to your family or to other dogs.” The carrier/shedder state seems to be the hardest part to understand about leptospirosis and may be one of the reasons why there is still not enough known about the disease.

Disinfection/Prevention

Suspected or infected animals should be isolated. Special precautions should be used if you think you or your dog has been exposed to the leptospirosis bacteria. It is recommended to wear gloves and/or wash your hands thoroughly after giving oral medications or cleaning up urine. Try not to allow an infected pet to lick people on the face or hands. Dry urine is not contagious since the leptospirosis bacteria die in a desiccated state.(9) Freezing, heat, and disinfectants will also destroy the bacteria. Antibacterial agents, bleach, and iodine-based solutions work well to kill the leptospires. Separating toys and water bowls may be a good idea if you have multiple dogs in your household. On that note, however, Classie was not diagnosed until several weeks later. Therefore, I never separated water bowls or toys and our other greyhound, Omaha, never showed any signs of infection. Being sanitary and controlling the rodent population will also help. Other suggestions for preventing exposure include keeping your dog on a leash, avoiding wet, flooded areas, and getting your pet vaccinated.

Vaccination

Paraphrasing the JAVMA article, “Because of the current vaccinations available, this disease may not be routinely considered in veterinary practice as a cause of acute kidney failure in dogs.”(3) Most recent outbreaks involve serovars for which vaccination does not exist. Until just recently only two strains, L. canicola and L. icterohaemorrhagiae, which are included in the common distemper, hepatitis, leptospirosis, parainfluenza, and parvovirus (DHLPP) shot have been available for more than 30 years. In 1999, Fort Dodge released a new vaccine that includes two more strains, L. pomona and L. grippotyphosa. That is still only four strains of many that can infect our canine friends. In addition, according to several sources, it is possible that coverage will only last for a six-month period. This means that if you are only vaccinating your dogs annually, they may still become infected. In endemic areas, more frequent vaccinations might be beneficial to prevent the renal carrier state and the disease.(13) Another concern seems to be allergic reactions and/or side affects associated with the leptospirosis portion of the vaccine. These can range from hives and swelling to life-threatening anaphylactic shock. The vaccine can be made to omit the leptospirosis portion. Mr. Serby also states that Fort Dodge claims this new vaccine reduces the problem of anaphylactic (allergic) reactions.(9) Vaccination will reduce the severity of disease but will not prevent infected dogs from becoming carriers and does not provide immunity against any other strains. Some veterinarians have stopped using the leptospirosis vaccine because they have never seen any cases in their area and because of the risk of adverse reactions. There is also evidence that dogs vaccinated for leptospirosis can become infected and shed the organism in their urine while remaining asymptomatic.(12) Any dog may show antibody titers to vaccination, which decrease after a few months.

Both our Greyhounds had been vaccinated with the original DHLPP vaccine, and they have now had the updated Fort Dodge leptospirosis vaccine with no side affects. After what Classie has been through, I feel the risk of reaction outweighs the possible consequences. I would highly recommend having your dogs vaccinated with the new Fort Dodge “7 in 1” vaccine. A flyer sent out by our veterinarian states that canine leptospirosis is a dangerous threat to dogs, and they are now recommending this new vaccine for their canine patients.

Conclusion

Please remember that leptospirosis is a life-threatening disease, so be wary of the signs and symptoms and advise your veterinarian on this information should the need arise. Leptospirosis is a very serious disease which unfortunately many licensed veterinarians are ill equipped to timely diagnose and treat. It is therefore incumbent on the dog owner to educate the treating professional to ensure that (s)he is aware of the possibility that the dog has leptospirosis and to monitor the treatment accordingly, or to use this knowledge to find a vet who knows what (s)he is doing.(9) For all you feline owners, please take note that cats are rarely infected because they are considered to have a kind of immunity from their long-time association with rodents. As we continue to encroach on areas that were inhabited by wildlife, we may see an increase in diseases like leptospirosis that have reservoirs of infection in many species of animal.

Webmistresses note: Classie lived out the rest of her life as a healthy greyhound and passed away at 13.

References

1 “Diagnosis of Leptospirosis: A Reemerging Disease of Companion Animals”, Seminars in Veterinary Medicine and Surgery (Small Animal) 1996; Vol. 11, No. 3: 166-71, by C.A. Bolin, DVM, PhD.

2 “Leptospirosis”, Infectious Diseases of the Dog and Cat 1998; 2nd Ed.: 273-81, by C.E. Greene, DVM, MS; M.A. Miller, DVM, and C.A. Brown, VMD, PhD.

3 “Leptospira interrogans serovar grippotyphosa infection in dogs”, Journal of the American Veterinary Medical Association (JAVMA) 1996; Vol. 209, No. 7:1265-7, by C.A. Brown, VMD, PhD; A.W. Roberts, MS; M.A. Miller, DVM; D.A. Davis, BS; S.A. Brown, VMD, PhD; C.A. Bolin, DVM, PhD; J. Jarecki-Black, MD, PhD; C.E. Greene, DVM, MS, and D. Miller-Liebl, DVM, PhD.

4 “How I Treat Leptospirosis”, North American Veterinary Conference Proceedings 2001: 255, by R.K. Sellon, DVM, PhD.

5 “Treatment and Outcome of Dogs with Leptospirosis: 36 Cases (1990-1998)”, Journal of the American Veterinary Medical Association (JAVMA) 2000; Vol. 216, No. 3:371-5, by C.A. Adin, DVM and Dr. L.D. Cowgill, DVM, PhD, DACVIM.

6 “Canine Leptospirosis in New Jersey and Michigan: 17 Cases (1990-1995)”, Journal of the American Animal Hospital Association (JAAHA) 1996; Vol. 32:495-501, by K.R. Harkin, DVM and C.L. Gartrell, DVM.

7 “Pathogenesis of experimental leptospira interrogans, serovar batavaie, infection in the dog: microbiological, clinical, hematological, and biochemical studies”, American Journal of Veterinary Research 1978; Vol. 39:449-54, by Dr. K.P. Keenan, Dr. A.D. Alexander, and Dr. C.A. Montgomery.

8 “Leptospirosis, Brucellosis, and Other Bacterial Infectious Diseases”, Saunders Manual of Small Animal Practice 2000; 2nd Ed.:133-5, by R.G. Sherding, DVM.

9 “Canine Leptospirosis”, (www.dnet.net/personal/cottrell/victor.htm), 2000, by Victor Serby.

10 “Infectious Diseases, Leptospirosis”, Dog Owner’s Home Veterinary Handbook 1980; 1st Ed.:46-7, by D.G. Carlson, DVM and J.M. Griffin, MD.

11 “Canine Leptospirosis”, Compendium of Continuing Education Small Animal 1996; Vol. 18, No. 11:1215-25, by J.S. Wohl, DVM.

12 “Spirochetal Diseases,” Canine Medicine 1979; 4th Ed., Vol. 1:61-3, by D.K. Chester, DVM, MS.

13 “Leptospirosis in Dogs”, Compendium of Continuing Education Small Animal 1987; Vol. 9, No. 5:499-507, by C.J. Baldwin, DVM, MS and C.E. Atkins, DVM.

CG SU 01