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3 Life-Threatening Dog Diseases to Know

3 Life-Threatening Dog Diseases to Know

From duck blind to briar patch, hunting dogs are experts at getting into trouble. Barbed wire, hypothermia, and altercations with wild animals or other dogs are Constant threats, and any one can sideline your hunting companion in seconds. Savvy hunters avoid these situations when possible, carry first-aid kits in their vehicles, and have their veterinarian's phone number on speed dial.

A vest will help prevent abrasions in thick cover, but there are still plenty of microscopic things that can lead to dog diseases.

Yet there are dangers in the outdoors that make that barbed wire fence or ornery porcupine look like playground hazards. The list sounds like something out of a bioterrorism novel: blastomycosis, Lyme disease, cyanobacteria poisoning. All of these unseen pathogens are common to certain hunting areas, and each one can sicken your four-legged hunting partner in days, hours, or even minutes.

By recognizing the early warning signs of some of these dog diseases, and getting prompt medical treatment, you can salvage more than just your hunting season; you could very well save your dog's life.


"Oh no," I said, watching my dog limp into the farmhouse kitchen. "Not again." It was the fourth day of a week-long hunting trip to North Dakota, and my black Lab, Gunner, had been performing well. Until, that is, he woke up with an extremely tender paw — almost the exact same condition that had led to a diagnosis of Lyme disease the previous year. This year the swelling was much more pronounced, more like a case of elephantitis than simple inflammation.

A quick examination revealed a slight lesion on the front pad, with no particular soreness in any of the toes or joints. Convinced it was a simple puncture wound, probably caused by wheat stubble, I applied some antibiotic cream and gave Gunner a few days of rest. He, in turn, spent the days watching soap operas, eating leftovers, and getting sicker.

A week later I was standing in front of a pharmacy technician, holding my credit card in sweaty fingers. Gunner was at home, his foot badly swollen and unable to bear any weight. The swelling and small lesion wasn't from wheat stubble; a trip to the vet had revealed his lameness had been caused by the fungal pathogen blastomycosis, commonly called blasto.

"You must really like your dog," the pharmacy technician said, ringing up my $220 purchase, which would last a couple weeks. Gunner would need six month's worth of Sporonox. I, in turn, would need to get a second job or sell a few shotguns.

Dog diseases

There was little choice in the matter; left untreated, the blasto fungus would slowly migrate throughout the body, turning tendons into mush, colonizing the lungs and creating the interior lesions that often cause a deep, hacking cough. (They'd eventually affect the brain, too, but in Gunner's case they might give up after a few months — I've been searching unsuccessfully for his brain for almost five years.)

A diagnosis of blasto is sobering, and the really scary part is there just isn't much you can do to prevent it. There is no vaccine, and simple avoidance is tough; blasto fungus thrives in marshes, swamps, and the rich dander of forest floors. This is also prime habitat for gamebirds ranging from geese to woodcock, which leave their scent mingled right in with the blasto fungus.

"These dogs are born and bred to locate game by scent," says Dr. Don Goebel, D.V.M. and co-owner of Crow-Goebel Veterinary Clinic. "That means their noses are down in the ground, snuffling in all those intriguing smells. If the blasto fungus is present, odds are some of the spores will enter the dog's body."

By itself, this isn't a big deal. Dogs, like humans, play temporary host to a wide variety of nasty bugs (if you doubt that,watch where your dog puts his tongue on a daily basis). Healthy dogs eliminate the fungus through their normal immune response. Other dogs, worn down from the rigors of hunting or other illnesses, may allow the fungus to take root.

So what to do? Preventing a hunting dog from sticking his nose into mulch is like asking him to quit barking at strangers. About the only way to prevent serious blasto is to monitor your dog's physical condition. Sudden lameness, weeping lesions on the feet, or a hacking cough are all common symptoms of blasto. Make sure you take your dog to the veterinarian promptly if your dog develops any of the above symptoms.

High-prevalence blasto areas are located within the watersheds of the St. Lawrence Seaway and the Mississippi and Ohio River basins. It's also common in the southeastern states. A quick phone call to your veterinarian or local kennel club should give you a good idea about the prevalence of blasto in your area.

The newest anti-fungal treatment for blasto, itraconazole, appears to be more effective and have fewer side effects than some of the treatments used a few years ago. When it comes time to break out the wallet, do some research; Canadian pharmaceutical companies are prohibited from advertising, resulting in some significant deals for the same drug.

Lyme Disease

First diagnosed in Connecticut more than 30 years ago, Lyme disease is carried by the deer tick, common in the Northeast and much of the Midwest. Only about 30 percent  of deer ticks carry the bacterium responsible for Lyme disease, Borrelia burgdorferi.

There's a very good vaccine that prevents Lyme disease, and dogs in the early stages of infection respond well to antibiotics. Still, hundreds of undiagnosed dogs die from the disease every year. Gunner almost joined them; I thought he was simply worn down from a long week of chasing divers around North Dakota potholes. This was in 2006, back when my veterinarian drove a Ford instead of a Cadillac.

"Lyme disease can be sneaky," says Dr. Goebel. "It incubates in the body in a dormant stage, then manifests symptoms when the animal is under stress. This big, muscular dog is jumping around like a pup one day, then walking like its joints are made of glass the next. Many hunters logically think the dog was physically injured."

Algae poisoning can quickly become fatal, so carefully check out any bodies of water before sending your dog for a retrieve.

The onset of this dog disease can happen almost overnight, and one of the most common symptoms of Lyme disease (like blastomycosis) is a sore foreleg. Lyme disease, however, will not involve weeping lesions or a deep cough. Fever and decreased appetite are also good indicators of a Borrelia infection.

"Examine the foot carefully," Dr. Goebel suggests. "If there's no obvious injury, your dog wasn't vaccinated, and you live in area where Lyme disease exists, it's very possible your dog is experiencing a rapid onset of Lyme disease. A simple blood test can determine the presence of the Borrelia bacterium."

Once dosed with antibiotics, the transformation from a pain-addled, lethargic dog to rambunctious mutt can occur overnight. Left untreated, though, Lyme disease will eventually affect kidney function. In some cases, the dog will show none of the obvious external physical symptoms, like a sore paw or sudden weight loss.

Inside the body, however, the kidneys are under attack, suffering irreparable damage (a condition called nephritis). Unable to process wastes, the dog is slowly poisoned. Weight loss, fever, and stiffness in the joints are all also common symptoms of Lyme disease.

Tall grass and brushy areas usually have the highest concentrations of deer ticks. These places also have another fitting adjective: birdy. Your odds of finding a tiny deer tick in 15 square feet of dog hide are about as good as a Pug winning a retriever trial, so if you live in a part of the country where deer ticks are prevalent and your dog spends time outdoors, get the vaccination.

Deer ticks are more active in spring and fall, so even those hunting dogs that spend 10 months or more inside the house or kennel need the Lyme vaccination.

Flea and tick collars, dermal treatments like Frontline, and frequent inspections around tick-nirvana — your dog's ears, neck, and armpits — all further reduce your dog's chances of contracting Lyme and other tick-related diseases.


A few years back, a rash of sudden hunting dog deaths during the opening days of the South Dakota pheasant season broke dozens of hunters' hearts. The early season was hot and dry, and the deaths were originally blamed on dehydration and heat stroke. Later on, however, it was determined that at least some of these dogs died from cyanobacteria poisoning.

In late summer and early fall, cyanobacteria — also called blue-green algae or pond scum — will often bloom in freshwater and, to a lesser degree, estuarine or marine waters. This is prime training time, and also coincides with early teal and upland bird hunting seasons. If your dog drinks water containing cyanobacteria, or even ingests some while grooming its coat after a swim, the results can be disastrous. In several cases, dogs have died within 15 minutes of exposure.

Dog Diseases born in water

Cyanobacteria thrive in warm, nutrient-rich, relatively stagnant water, so before you start dropping bluewings into that pothole, take a close look at the water. Foams, scum, or mats on the water are all indications of blooms. While not all blooms are toxic, it's best to not take a chance; the by-products produced by cyanobacteria metabolism are some of the most poisonous natural compounds on earth, easily capable of killing thousand-pound cattle.

The symptoms can vary depending on the animal and type of bloom, but vomiting, convulsions, and skin lesions are all typical signs of exposure. An immediate trip to the veterinarian is essential to prevent serious damage to the nervous and digestive systems.

If you hunt or train near water that could contain cyanobacteria, bring along plenty of clean water for drinking. Wash your dog's coat to remove residual scum after swims, and don't make him retrieve dummies in scummy water — the dog's open mouth will act like a funnel, channeling toxic water directly into its stomach.

Bottom line: Dogs are tough and brave critters, capable of enduring high levels of pain and stress. Once they start showing signs of an illness, odds are good that the dog disease has progressed to a point where a vet needs to take a look. Don't hesitate; after all, we are our dog's keeper, his advocate and guardian, the one who knows the dog better than he knows himself.

We have to speak for our dogs, because they sure aren't going to tell us when they feel a little funky. It might require a little time and money, but they're worth it.

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