Managing intestinal parasites in sled dog kennels
Maintaining a kennel of healthy sled dogs requires a far different approach than what may be deployed effectively for a single house pet. Large numbers of dogs grouped together, with exposure to other very large groups of dogs at races, on trails, and when traveling, are best served with fecal monitoring, and an ongoing rotation of anthelmintics (dewormers). This article will be limited to intestinal worms (helminths), and not include the protozoan giardia or coccidian.
The most important parasite management tool of them all is: your poop shovel. Clean the kennel every day. Mine gets cleaned a minimum of twice daily and often more. There are no chemicals known that can destroy the eggs of these parasites. Clean thoroughly!
Another good idea is to periodically bring a fecal sample to your veterinarian for fecal centrifugation/flotation. Like most medical tests, it is not perfect, as some parasites (whipworm especially) only shed eggs intermittently, and tapeworms are very hard to detect on a float, but it will help you adjust your deworming program if needed. Different parts of the country have varying incidences of certain parasites, so talk to your veterinarian. Establish a relationship with your veterinarian so you can work together to improve your animal husbandry.
Do not fall for the incorrect belief that if your dogs have no worms in the feces they are worm free. It is simply flat out wrong.
Lets talk tapeworm (Cestodes, the flat worms) as they are bit less complicated to manage, although their life cycle is extremely complicated. Tapeworms cannot be transferred from dog to dog via egg contamination on the ground, or by dams transmitting to puppies. The dog only gets the worm from eating the intermediate host that carries the tapeworm. For Dipylidium tapeworm, the intermediate host is the flea; for Echinococcus and Taenia, it’s prey animals, such as mice, rabbits, moose, caribou, deer and so on. Tapeworms do not shed eggs in feces, they shed segments, which contain egg packets, so they can be easily missed on a routine fecal float by your veterinarian. If you look at an adult tapeworm from a dog, you can see that the body is segmented. The segments near the tail of the worm break off, are defecated on the ground by the dog, and then consumed by the intermediate host, and the cycle goes around again. Segments in dog poo can sometimes be seen with the naked eye. Dipylidium and Echinococcus are rather oval and they are very tiny; Taenia can be a long as grain of rice and are more square. Sometimes they are moving.
Using generic drug names here are products for treatment of tapeworms:
Praziquantel: kills only tapeworm, and is the only one that kills all three species of tapeworm most commonly found in dogs (Taenia, Dipylidium, and Echinococcus).
Fenbendazole: kills only Taenia species tapeworm.
Please note that Echinococcus is a human health concern as it causes alveolar cyst disease in humans, which can be fatal. Transmission to human is fecal-oral from infected dog feces. I am aware of at least one musher who has been afflicted with this. Echinococcus is endemic in northern latitudes. At this writing I’m aware that it is being found more often in the lower 48 states.
Dogs in northern latitudes should be treated for tapeworm with praziquantel a minimum of once yearly. Dogs get tapeworm from eating raw or undercooked meat from game animals, or the occasional suicidal hare or mouse etc. that wanders too close. While freezing meat at very cold temperatures (less than -20°F) is often claimed to be adequate to kill the infectious form of the tapeworm, there is no really solid research out there on how cold and for how long in what size chunk of meat from which source is enough. Don’t take the chance. Cook all game meat thoroughly. If you feed a lot of game meat, I would recommend using praziquantel at least twice yearly.
Nematodes, or round shaped worms, including Roundworm, Hookworm, Whipworm, are more complicated to manage as they all shed eggs that can survive in kennels through all extremes of temperature, dryness and moisture, especially whipworm. All of these parasites can affect nutrient absorption, damage and disrupt intestinal function and will certainly affect performance as a result.
Roundworm have numerous ways to infect dogs. They infect puppies by crossing the placenta to infect a fetus, are transmitted through milk to nursing pups and shed large volumes of eggs, which are defecated in feces, larvate and are then ingested by the dog. You should assume every puppy comes complete with roundworms on board. Humans can also be infected with these worms. Diarrhea, dull coat, poor weight gain in pups and pot bellied pups are noted with roundworm infestation.
Hookworm can also be transmitted from dam to pup via milk as well as egg contamination on the ground. They feed on blood from the intestinal lining, and can cause anemia, especially in pups, as well as bloody diarrhea. The eggs are very hardy. In humans, walking barefoot on ground contaminated with hookworm larvae can cause cutaneous or visceral larval migrants. Hookworm dermatitis from large numbers of larvae migrating through a dogs skin is another potential problem.
Whipworm can cause weight loss, diarrhea, bloody diarrhea, even death or a syndrome similar to Addison’s disease. The eggs live for up to two years through all conditions. If whipworm is found in your dogs, your management must assume they are always there, unless you do a round of fenbendazole and move the dogs to completely virgin ground the next day; even then I would assume that a few are still around.
Products for treating nematodes as available in the USA: This is not a complete list, these are the products that are most commonly deployed at this time.
Pyrantel pamoate: treats roundworm and hookworm only.
Febantel: is converted by the dog’s body into fenbendazole. Typically only found in combination dewormers at time of this writing, such as Drontal Plus®.
Fenbendazole: treats roundworm, hookworm, whipworm, (and Taenia species tapeworm).
Milbemycin (Prescription) This drug is used as both a heartworm preventative and to help treat and control roundworm, hookworm and whipworm. As such, many veterinarians will require annual heartworm testing to dispense it in heartworm endemic areas. I have seen this prescribed by veterinarians to help manage whipworm infestations, but I haven’t been all been able to rely on it for that particular purpose in my own patients (I found it very necessary to use other dewormers in rotation). It is also sold in combination form with praziquantel, which can be used to treat tapeworm.
Ivermectin: No longer recommended due to risks associated with MDR-1 mutation (i.e. seizures, blindness), this product is only recommended at that “old” deworming dose for use to treat demodectic mange in non MRD-1 mutation breeds. My impression was that it was never particularly effective for nematodes. The heartworm prevention dose is still very widely used and is safe.
Nematode management suggestions:
Start by taking fecal samples from several dogs and submitting them to your veterinarian for fecal centrifugation. Do this two or three times yearly. Do not let consecutive negative fecals convince you that your kennel is worm free. Not all parasites shed eggs or segments in ways that are easy to detect. Your dogs will travel, new dogs will arrive, people will visit, and so on. Even with negative fecals, kenneled dogs will need deworming, and usually more than once yearly. This is a tool in your pocket, a way to see if anything new has been dragged home by these opportunistic scavengers we love so much.
For young puppies, roundworm and hookworm are the primary concerns. I start deworming my pups at two weeks of age with pyrantel pamoate, and give it every seven days until they are six weeks old, at which time I use fenbendazole three days in a row. If fecal checks are showing no roundworm eggs I may reduce the pyrantel to every 14 days, and treat again with fenbendazole at 14 and 18 weeks. While I have no published articles about resistance to back this up, it has been my observation that pyrantel pamoate seems to be losing it’s punch against roundworms in dogs, and I have seen several litters of pups struggle with roundworm burdens until they are old enough for fenbendazole. Fenbendazole products are still labeled six weeks and older, although it is the only drug labeled safe to give to pregnant bitches. Pyrantel pamoate is very safe for young puppies.
Adult dogs: when I lived in the lower 48 I dewormed monthly, rotating pyrantel pamoate and fenbendazole, and occasionally rotated in ivermectin. I stopped using Ivermectin years ago. I still deworm every one to two months, being sure to rotate both products and deworm annually with praziquantel. There have historically been fewer incidences of hookworm and whipworm in Alaska, but recently there has been increasing problems with both of these parasites in the far north. If you have a roundworm or hookworm problem, you should start by using either pyrantel or fenbendazole, treat again in two weeks, again in four weeks, and then monthly. Whipworm has a slower life cycle: for managing whipworm, start with fenbendazole now, three weeks from now and then every three months.
Dawn Brown DVM started racing in the junior classes in 1982 while handling for Pat Quinn's kennel of racing Siberian Huskies. She spent a total of eight years handling for Pat and later another four years for the research sled dog team at Cornell University while she was a vet student. She graduated in 1995 and finally started her own kennel. Since then she has driven all over the United States and Canada racing in 6, 8 and 10-dog sprint events. After multiple road trips from NY to race in Alaska, she moved there permanently in 2012 and now enjoys beautiful trails from her back yard in Salcha, Alaska, and competitive races within a few hours drive instead of a few days. She is a multiple ISDRA medalist, and currently holds multiple track records in Alaska and the Lower 48 states. She is the secretary of the Alaska Dog Mushers Association and Director at Large for the International Sled Dog Racing Association. She is the Chair of the Veterinary Committee for the ADMA and the Head Veterinarian for the Open North American Championship. She has provided veterinary care at numerous sprint racing events in the Lower 48 states and Alaska. She practices small animal medicine and surgery in North Pole, Alaska.