Spike in Michigan canine lepto cases
Veterinarians at Michigan State University's College of Veterinary Medicine are warning of an upswing in leptospirosis in dogs in the Detroit area. More than 20 cases of leptospirosis have been reported in dogs in the Detroit area, and it's likely that many more unreported cases have occurred. Leptospirosis, a bacterial infection, can cause very serious disease, including potentially fatal renal failure. It can be vague and hard to diagnosis if people aren't thinking about the disease. The most commonly identified problem is kidney disease, and early diagnosis and treatment is critical for successful treatment.
The Leptospira bacterium can survive well in the environment, particularly in moist conditions, and dogs are often exposed through wet environmental areas that have been contaminated with leptospires from the urine of infected wildlife. The strain that has predominated in the latest Michigan cases is Leptospira Icterohemorrhagiae, a type most often associated with rats.
Prevention of leptospirosis involves avoiding exposure to the bacterium as much as possible (largely through avoiding contact with wet areas where lepto cases have been identified) and vaccination. Vaccines are available for dogs and they can reduce the incidence and severity of disease caused by four different lepto types, including Icterohemorrhagiae. Vaccination should be considered in dogs in regions where lepto cases are identified and in dogs at increased risk of exposure based on lifestyle and travel.
Leptospirosis vaccination in dogs
Leptospirosis is disease caused by several types of Leptospira bacteria. It's often called a re-emerging disease in dogs, because the incidence has been increasing over the past couple of decades in many areas. While the overall number of infections is limited, when it does occur lepto can cause serious disease, including kidney failure. It's also a zoonotic disease: lepto can be transmitted from sick dogs to the people who handle them. Infected animals shed the bacteria in their urine, and when the urine comes in contact with broken skin or mucous membranes (mouth, eyes, nose), transmission of infection can result.
Canine vaccines against lepto are available. In the past, lepto vaccination hasn't been all that popular because the vaccines tended to have a higher rate of side effects compared to most vaccines, and the types of lepto that the vaccines targeted were often not the most important types causing disease. This has changed more recently as newer vaccines have become available. These vaccines seem to have low rates of adverse effects and provide protection against the four types of lepto that tend to be the most important. These vaccines have also been shown in research studies to protect against disease and to reduce shedding of the lepto bacterium in urine (thereby decreasing the risk of transmission to other animals or people).
Lepto is not among the "core" vaccines that groups say all dogs should have. That's because the risk of lepto exposure varies greatly between regions and dogs. The key thing to consider when deciding whether or not to vaccinate is what each individual dog's risk of exposure is. The main reservoir of lepto is wildlife such as rats and raccoons. If infected wildlife are in the area, they may be peeing out lepto and contaminating the environment, particularly any type of standing water (lepto loves to live in warm, wet environments).
In the past, much of the concern has been focused on dogs that go out and swim in streams or ponds. The "poster child" for lepto has typically been the Labrador Retriever that goes out gallivanting in the bush, but that may be changing too. When you consider where wildlife such as rats and raccoons live and how high the wildlife infection rates can be, remember that these pests can be present in urban areas in incredibly large numbers. Living in a city does not make a dog safe from exposure to lepto. In fact some urban areas, with large numbers of wildlife crowded into high-traffic areas like parks, are probably higher risk than rural areas.
Deciding on vaccinating requires an understanding of how common lepto is in the area and whether there is a risk of exposure for the individual animal. This is a disease for which a veterinarian's understanding of disease patterns in an area (including any specific areas that be particularly high risk) and the types of possible exposure of the dog play a big role. There's no "one size fits all" recommendation for lepto vaccination.
Leptospirosis death: UK
British champion rower Andy Holmes has died of leptospirosis, which was suspected to have been acquired from the water during the annual Boston Rowing Marathon on the River Witham (UK) in September. The 51-year-old Holmes, an accomplished Olympic rower from the 1980s, started to feel unwell in the days after the race, and developed a fever. He was subsequently diagnosed with Weil's disease, a serious form of leptospirosis that can cause liver failure.
In some ways, this is being written off as a very rare and unfortunate event. It's always hard to determine how aggressive to be when making recommendations about avoiding infections that can be acquired from common recreational and occupational activities.
The race's welfare officer stated "Part of any rower's training is being warned about water safety. If you fall into water you must wash thoroughly and if you think you have ingested any water seek medical advice." The problem is, exposure to water during rowing and similar events is basically unavoidable. Splashes of small amounts of water into the eyes, nose, mouth or cuts/scrapes could be enough to inoculate potentially harmful microorganisms into the tissues. People aren't going to run to the physician after every potential exposure. Knowing whether or not the water source has previously been implicated in leptospirosis infections may be useful, but it doesn't tell you anything for certain.
General recommendations for people working around water include:
- Covering cuts and sores with waterproof bandages.
- Washing hands, particularly before eating.
- Avoiding contact of water with the eyes, mouth and nose, whenever possible.
- Avoiding ingestion of any amount of water.
- Ensuring their physician knows about the potential for water exposure should they become sick.
Obviously, complete avoidance of water exposure is impossible for many people, and the overall risk is very low. Weil's disease is a rare condition but it does occur, both as sporadic cases and large outbreaks. It's usually treatable but can be fatal, so it shouldn't be dismissed.
Issues with pets and leptospirosis are similar. Pets, mainly dogs, become exposed from contact with water that has been infected by Leptospira bacteria from the urine of infected wildlife. Infection can cause a broad range of disease in dogs as well, from subclinical to acutely fatal. Vaccines for certain strains are available for dogs who are at higher risk of exposure. Talk to your veterinarian about whether your dog should be vaccinated against leptospirosis. More information about leptospirosis in dogs and cats is available on the Worms & Germs Resources page.
Image: Andy Holmes sits behind Steve Redgrave after winning a gold medal for Britain at the 1988 Seoul Olympics.
Canine leptospirosis warning: Ontario
Veterinarians are reporting a potential cluster of leptospirosis cases in dogs near Lake Aquitaine in Mississauga (Winston Churchill Blvd. & Derry Rd. area). Leptospira gryppotyphosa has been confirmed in one dog, with other cases being suspected but not confirmed because owners declined testing.
Leptospirosis is a bacterial infection caused by different types Leptospira spp. These bacteria like to live in water and in moist conditions, and infections in dogs most often result in kidney disease. The bacterium is shed in the urine of infected animals. Leptospira gryppotyphosa is mainly found in wild voles, raccoons, skunks and opossums, and these animals can infect various environmental areas. Any animals exposed to outdoor environments in endemic areas can become infected from ingesting infected water or from contact of infected water with the mouth, eyes or nose, or cuts or other broken skin.
People in the area where these cases have been found should take particular care and probably avoid letting their animals wander into the water or wet areas. A vaccine is available to reduce the risk of leptospirosis, including disease caused by this Leptospira type. Vaccination of pets that are exposed to water or wet habitats in areas where lepto is present is a good idea. People in the Lake Aquitaine area should be particularly vigilant and vaccination of pets would be a good idea.
Leptospirosis in Michigan
Veterinarians are reporting an apparent spike in cases of leptospirosis in dogs in southern Michigan. Leptospirosis is considered a re-emerging disease in many areas of North America. This disease, caused by various types of the Leptospira bacterium, can affect many different species, including dogs and people. A wide range of illnesses can result, including fatal infections. In dogs, kidney failure is a common problem.
Classically, leptospirosis is diagnosed in dogs that spend time in the woods and similar areas, where they may be exposed to the bacterium from contact with the urine of infected wildlife. Different types of Leptospira have different animal hosts, and infected hosts can shed large numbers of bacteria in urine. These bacteria can survive in wet conditions for long periods of time, and other animals can be infected through ingestion of urine-contaminated water or contact of urine-contaminated water with broken skin (e.g. tiny cuts or open sores on their feet) or mucous membranes (eyes, mouth, nose).
Michigan vets have suggested that the recent spike in cases is the result of local highway construction, which may have driven rats out of their normal habitats and into areas that people and dogs frequent. That's possible, but it could also be increasing natural re-emergence of the disease, or increasing recognition of the disease, as more attention is being paid to it. Regardless, an understanding that this disease is a problem in the area is important to allow for prompt diagnosis (and proper treatment), as well as preventive measures.
A vaccine is available, but it is not 100% protective and only protects against certain strains of Leptospira. Nonetheless, it's still a good idea in areas where disease is caused by the strains present in the vaccine and when dogs have a reasonable chance of being exposed.
People can also get leptospirosis. Most often, they are exposed just like dogs: from the outdoor environment. However, pet-to-human transmission has been reported, mainly involving pet rats (since rats are an important reservoir host). People who have contact with an infected dog must take precautions to reduce the risk of transmission. This includes avoiding contact with urine, good attention to personal hygiene (especially hand washing), and proper cleaning and disinfection of any areas potentially contaminated with urine. Prompt diagnosis of canine lepto is very important because treatment rapidly stops the animal from shedding the bacterium. The earlier it's diagnosed, the quicker it can be treated, and the less contamination can occur.
More information about leptospirosis and Leptospira is available on the Worms & Germs Resources page, and in our archives.
Leptospirosis and cold weather
When we have a -30C windchill and snow on the ground, my first thoughts usually aren't about survival of bacteria in the outdoor environment. However, some microorganisms are well adapted for survival in various adverse conditions and we shouldn't assume that cold=dead for every bug of concern. Along that line, we received a question recently about survival of Leptospira and I passed it along to our lepto expert, Dr. John Prescott. Here's his guest post:
A reader in Ohio owns a dog that had leptospirosis, and had some questions about leptospirosis that may be of general interest.
Q1. Since the yard is likely contaminated with leptospires, she asked “How cold does the temperature have to get before the Lepto organisms are killed?”
A1. Once it’s frozen, as it is now in January, they’re dead. Leptospires are fragile bacteria that are killed by dry heat and by freezing. They survive well in moist or wet environments, with moderate temperatures. In some countries leptospirosis is called “mud fever” or “fall fever” since this description captures so well the environmental conditions under which they thrive.
Although leptospirosis in dogs can occur at any time in the year, it mainly causes disease in the fall, late September to December, peaking in November. The increasingly mild and prolonged falls that we have experienced in the last decade are thought to be an important reason that leptospirosis has resurged in dogs. Interestingly, there is often a “blip” of leptospirosis in dogs in March in Ontario (and likely Ohio), since this is when the snow melts and conditions are wet, even though we can still get freezing at that time. I suspect that this is also the time when the raccoons that are thought to be the main source of leptospirosis for dogs are again active after the winter, and are foraging for food for themselves and their babies.
Q2. Do dogs still shed leptospires after they’ve been treated?
A2. No. Leptospires are quickly killed by the antibiotics used in treatment, amoxicillin or doxycycline. There is no danger that dogs treated for a week with these drugs are a risk to people or other animals. You may read in otherwise very reputable textbooks that these antibiotics “do not eliminate the carrier state” but I have no idea where this misunderstanding comes from.
Q3. Where can I find out more about leptospirosis in dogs?
A3. I like the web site http://www.leptoinfo.com, which is maintained by a vaccine company. I was surprised how many web sites devoted to leptospirosis that there are, but like much on the internet some contain highly misleading information. The “Worms & Germs” site has good past blogs about canine leptospirosis and is usually (just kidding, Scott) a reliable source of information.
One very common entrenched misconception, which is very hard to kill, is that vaccination does not stop animals shedding the organism. This is quite wrong. I suspect this misconception came from an experimental study half a century ago when dogs with pre-existing kidney infection with a leptospiral serovar called Canicola were vaccinated. It would not be expected by anyone that these animals would stop shedding since antibodies don’t penetrate into the place in the kidney where the leptospires live and from which they are shed in the urine. What vaccination does incredibly effectively is to prevent leptospires from actually reaching the kidney and setting up home there. The leptospires are removed by antibodies in the blood, so they never reach the kidney.
Canine lepto: It's that time of year again
The latest newsletter from the University of Guelph's Animal Health Laboratory contains a brief update on the percentage of positive MAT tests for canine leptospirosis that the lab has seen in the first half of 2009. Approximately 30% of the tests have been positive, which is up from the previous two years. However, the prime time for lepto cases (and therefore typically also lepto testing) is just starting: the cool damp fall weather provides a great environment for lepto bacteria to survive outdoors for the next several weeks.
Prevention of lepto in dogs, as with most diseases, is preferred to trying to treat sick animals. The best way to avoid the bacterium is to keep your dog out of areas where infected wildlife may urinate frequently, particularly out in the bush. But of course, skunks and raccoons can be found as close as the backyard as well, so even in the city the risk isn't zero.
If your dog does frequently go into the bush and is at increased risk for leptospirosis, hopefully you've already discussed vaccination with your veterinarian. While the vaccine available doesn't protect against all types of lepto, it does help protect against the most common ones - in Ontario, these are believed to be the lepto serovars grippotyphosa and pomona. We also received the following question from a reader the other day:
"Should a dog who has shown positive for early stages of kidney disease be vaccinated against leptospirosis? Can the vaccine accelerate the illness to acute renal failure?"
I can see where the question comes from, but the simple answer to the second part of the question is no. Although the infection can certainly affect the animal's renal function (and can push even healthy dogs into renal failure if it is severe), the vaccine works on the dog's immune system and does not affect the kidneys directly. The answer to the first part of the question is, of course, much more complicated, and depends on many other factors including the dog's overall health status, lifestyle and other risk factors, and vaccination history. The decision about whether or not to vaccinate your dog should be discussed on an individual basis with your veterinarian.
More information about leptospirosis is available on the Worms & Germs Resources page and in our archives.
Image: Scanning electron micrograph of Leptospira sp. bacteria (source: CDC Public Health Image Library ID#138))
Weil's disease from a pet rat
A recent edition of the Veterinary Record contains a case report of Weil's disease in a person that adopted a feral (wild) rat (Strugnell et al, 2009). Weil's disease is a severe disease of the kidneys, liver and other body systems that can develop after acute leptospirosis (infection by Leptospira bacteria). This group of bacteria can infect a wide range of animals and is typically shed in the urine. The person that was affected adopted the rat after it was caught by her neighbour's cat. The paper says that the rat was "urinary incontinent" - not something we usually notice about rats since they are not typically litter or house trained. I presume this means the rat was urinating frequently when out of its cage, including when it was being handled. Because of this, the owner reported that she "aimed" to wash her hands after every time she touched the rat.
A couple of weeks after adopting the rat, the woman was admitted to hospital because of lethargy, muscle aches, mild abdominal pain, cough and a bloody nose. Blood tests showed that she had decreased levels of white and red blood cells, as well as liver and kidney disease. After further testing she was diagnosed with leptospirosis. She had to be treated in the ICU, but eventually made a complete recovery. The adopted rat and the other rat that she owned were euthanized by the owner's partner shortly after she was admitted to hospital. Testing of the adopted rat identified Leptospira in the kidneys.
This is another example of why wild animals should be left in the wild, and another case highlighting the need for veterinarians, physicians and public health personnel to work together.
More information on Leptospira and leptospirosis can be found on the Worms & Germs Resources page and in our archives.
Leptospirosis and Pot-Bellied Pigs
Back in the 1980s, Vietnamese Pot-Bellied Pigs were a popular fad pet. These stout little oinkers are still out there, though they're not quite as popular as they once were. Potbellied pigs are cute (at least to some people... to each their own!), supposedly quite smart, and can even be house trained/litter trained. As with any new pet though, it's very important to do your research before going hog-wild and getting yourself a pot-bellied pig. Talk to your veterinarian about what your pig will need in terms of medical care - vaccines, deworming, spay/neuter, hoof trimming, tusk trimming... Because they are uncommon pets, some veterinarians may not be comfortable treating a pig. Make sure you ask ahead of time so you know to which veterinarian(s) in your area you can (and will!) take your pig.
We recently received a question about vaccination of pot-bellied pigs. Just like dogs, in some areas pigs need to be licensed by the city, and certain vaccines are required in order to obtain a license. In this particular case, pigs are required to be vaccinated against rabies, swine erysipelas and leptospirosis. Regular visitors to this site are no doubt familiar with the issues around rabies and why it's important to vaccinate for this deadly disease. (More information about rabies is available on the Worms & Germs Resources page and in our archives.) Swine erysipelas is a systemic bacterial infection caused by Erysipelothrix rhusiopathia, which can rarely cause a skin infection known as erysipeloid in humans. This is not to be confused with human erysipelas, which is a skin infection caused by various species of Streptococcus (particularly Streptococcus pyogenes).
But the question was about leptospirosis vaccination in pot-bellied pigs. Pigs are susceptible to infection by Leptospira interrogans, just like dogs and people, and if infected a pet pig would be equally capable of shedding the bacterium in its urine and potentially transmitting the disease. The issues around requiring vaccination of pigs for leptospirosis are very similar to those around making leptospirosis a "core" vaccine in dogs. More information about this is available in the Worms & Germs post entitled "Should all dogs in Ontario be vaccinated for leptospirosis?" A pet pig would likely be exposed to the same serovars of Leptospira as a dog kept in the same area, typically by coming in contact with urine from infected wild animals such as raccoons and skunks when they go outside. However, the risk of exposure for a pig that rarely or never leaves the house would be extremely low compared to a pig that has outdoor access. Another important consideration is whether or not the pig vaccine is against the same serovars that a pet pig, instead of a commercial pig, might encounter. This will also vary depending on in what area the pig lives. The Leptospira servoars pomona and bratislava are actually host-adapted to pigs.
It is also important to vaccinate an animal with vaccines that are labeled for use in its own species. Vaccinating a pig with a vaccine meant for dogs could have unpredictable results - it may increase the risk of an adverse reaction, or it may not adequately stimulate an immune response, thereby leaving the pig essentially unvaccinated. Your veterinarian can discuss the pros and cons of vaccination in your pet with the available vaccine products.
More information about leptospirosis is also available on the Worms & Germs Resources page.
Should all dogs in Ontario be vaccinated for leptospirosis?
The last decade has witnessed a surge in leptospirosis in dogs throughout much of North America. Ontario and Québec have been part of the surge, which is associated with two serovars of Leptospira, grippotyphosa and pomona.The reasons for the dramatic increase relate to: 1. The apparent spread of infection in raccoons and to a lesser extent skunks; 2. A changing climate that favours prolonged survival of these bacteria outdoors in the milder fall temperatures; 3. Perhaps to a minor extent increased awareness of the disease by veterinarians. Gillian Alton, a Masters student at the University of Guelph, has shown that the increased infection rate observed in recent years appears to have leveled off, which may be the result of widespread vaccination.
Leptospirosis should be suspected whenever there is kidney or liver inflammation of unknown origin, particularly in the fall of the year. In 2007, there were about 80 positive and 170 suspicious cases in Ontario based on blood tests submitted to the Animal Health Laboratory (AHL), University of Guelph. Since not all such blood tests go through the AHL, it is likely that there would have been about 160 positive and 350 suspicious cases based on this testing throughout Ontario, and an unknown number of cases diagnosed by PCR (a DNA-based test). If one includes cases diagnosed based on clinical signs but without laboratory testing, and about half the suspicious cases as positive cases, then there may be about 400 clinical cases (i.e. cases where the animal actually gets sick) of leptospirosis in dogs occurring annually in Ontario. Clinical leptospirosis in dogs is a serious disease and this number, if the assumptions are correct, represents a high burden of infection.
Arguments for recommending the new 4-way leptospiral vaccines as a “core” vaccine (i.e. all dogs should be vaccinated) in Ontario are:
- The suggested size of the problem;
- The often serious nature of the disease;
- The zoonotic potential of the infection (a small number of human infections acquired from dogs have been recognized in Ontario and Québec in recent years);
- The ongoing widespread presence and sometimes large numbers of raccoons in suburban and urban Ontario;
- The diagnosis of canine leptospirosis throughout the province;
- The diagnosis of the disease in dogs of all types, not just the “male hunting dog” which is sometimes conventionally regarded as “high risk”.
- The sporadic nature of the infection, including the lack of exposure of some dogs to raccoons and other wildlife sources;
- The number of vaccine reactions associated with leptospiral vaccines (this is not a significant problem with at least one of the vaccines);
- The considerable confusion caused by the (almost certainly totally unfounded) suspicion that serovar autumnalis causes canine leptospirosis, but is not in the new vaccines;
- The lack of inclusion of serovar bratislava in the vaccine (although this serovar seems to cause only mild disease in dogs);
- The annual cost of revaccination.
Camping with canines - tick tick not!
The warm weather is just about here, and that means the start of camping season. Lots of people love to spend time in the great outdoors during the summer, whether it’s at a summer cottage on the lake, trailer camping in a park with electricity and running water, or roughing it in a tent in the peace and solitude of a more remote wooded location. And many people bring along their faithful companions – their dogs – who enjoy the experience just as much, if not more, than we do.But there are also dangers lurking in the forests – microscopic dangers carried by tiny insects and other bugs. Ticks in particular are problematic. Certain ticks can carry a number of diseases that can make dogs sick, including Lyme disease (caused by Borrelia burgdorferi) and Rocky Mountain Spotted Fever (RMSF)(caused by Rickettsia rickettsii ). Both Lyme disease and RMSF are more common in certain areas where the tick species that carry them are present. You can NOT catch these diseases from your dog, but both you and your dog can be infected by the ticks that carry them. People can also be exposed to these pathogens by accidentally crushing an infected tick while trying to remove it from their dog. Ticks must be removed very carefully to ensure that the entire tick is removed, including the head and mouth pieces, without crushing it. If you're not sure how, contact your veterinarian. Also, the sooner the tick is removed, the less likely it is to transmit certain diseases, so be sure to check your dog thoroughly for ticks when you come back from a walk in the bush.
The Minnesota Department of Health recently reported that the number of cases of (human) Lyme disease increased in that state in 2007. This could be because of spreading tick populations, more people participating in activities in tick-inhabited areas, or increasing awareness and diagnosis of the disease by physicians.
If you and your canine companion will be spending time in some of the wilder and woodier parts of the great outdoors, talk to your veterinarian about what you can do to protect your dog. There are vaccines available for Lyme disease and the bacterial infection leptospirosis (which is also transmissible to people). Flea and tick preventatives are also very important, and many of today’s products are very effective. People should always wear insect repellent when camping or hiking in the woods. Visit the Health Canada website for safety tips on using personal insect repellents. All dogs should be vaccinated for rabies, whether they go camping in the backwoods or they’re house-bound city-slickers.
Information Sheets for Pet Owners
INFORMATION SHEETS specifically for KIDS, for VETERINARIANS, for PHYSICIANS and for PUBLIC HEALTH PERSONNEL are also available on the Worms & Germs RESOURCES page!
Click on the highlighted topics below for information sheets. Topics that are not highlighted are in development and coming soon. Sheets for other animal species and diseases are also under development and will be added when they are available.
| Animals | Diseases | Other |
| Dogs | Rabies | Litter Boxes |
| Cats | Giardia | Sandboxes |
| Turtles | Toxoplasma | Cat Bites |
| Hamsters | Leptospira | Raw Meat |
| Rabbits | Clostridium difficile | Petting Zoos |
| Pet Birds | Cryptosporidium | Needlestick Injuries |
| Reptiles | MRSA | |
| MRSP | ||
| Salmonella | ||
| Ringworm | ||
| Campylobacter | ||
| Bartonella henselae | ||
Please Remember:
- Your veterinarian and physician are your ultimate resource for information about the health of your pets or your family.
- Information provided here is accurate to the best of our knowledge, but infectious diseases can be unpredictable and these sheets are for general information purposes only.
- There can be great variation in disease risks in different geographic areas. The information provided was developed for Ontario, Canada, but most of the information is relevant for other regions as well.
