Basic Dog Diseases
Today we have vaccines to help prevent many of the killer dog diseases -- and antibiotics to treat some diseases when they do strike. With the proper series of preventative vaccinations, your dog will most likely never suffer any of the diseases listed in this section, but we've described them just in case.
The Not-So-Magnificent Seven
There are seven common and potentially fatal canine diseases you should protect your dog against with regular vaccinations: canine cough (also known as kennel cough), coronavirus, distemper, canine infectious hepatitis, leptospirosis, parvovirus (or "parvo" for short), and -- the most dreaded of all -- rabies.
Canine cough. This is a respiratory infection common to any situation where many dogs are kept together, such as kennels (giving rise to the name "kennel cough"), animal shelters, and pet stores. The infection causes the trachea, larynx (voice box), and bronchi (the little branching tubes in the lungs) to become inflamed. Succumbing to the bacteria Bordetella bronchiseptica, an infected dog will develop a mild to severe cough, sometimes with a runny nose, five to ten days after exposure. It can be treated with antibiotics and plenty of rest, which is very important. As with all the Not-So-Magnificent Seven, prevention is the most sensible and humane choice. If you plan to board your dog or will be exposing her to many other dogs, be sure she's protected against Bordetella. The "double whammy" is often a good strategy: a liquid vaccine administered through the dog's nose combined with an injection for canine parainfluenza virus.
Coronavirus. A usually mild disease, coronavirus is spread when a dog comes in contact with the stool or other excretions of infected dogs. Although it rarely kills dogs, coronavirus can be especially hard on puppies or dogs who are stressed or not in the best of health. Suspect coronavirus if your dog is depressed, doesn't want to eat, vomits -- especially if it's bloody -- and has a bad case of diarrhea. Exceptionally strong-smelling stools, particularly if bloody or with a strange yellow-orange color, are also signs. If coronavirus is diagnosed, the veterinarian will give your dog plenty of fluids to replace those lost from the vomiting and diarrhea, as well as medication to help keep the vomiting and diarrhea to a minimum. A coronavirus vaccination is usually recommended if your dog will be meeting lots of other dogs -- or their excrement -- at parks, dog shows, kennels, and other boarding facilities.
Distemper. Around the world, more dogs die from distemper than any other infectious disease. This highly contagious virus is spread by direct contact or through the air. A hale and hearty dog can survive distemper, usually with relatively mild symptoms. On the other hand, if your dog's immune system doesn't come out fighting, her whole body can be overwhelmed by the virus, as well as bacteria that jump in to cause secondary infections.
Distemper usually happens in two stages. Three to fifteen days after exposure to the virus, the dog develops a fever, doesn't want to eat, has no energy, and her eyes and nose become runny. As time passes, the discharge from her eyes and nose starts to get thick, yellow, and gooey -- the classic sign of distemper. If you haven't taken your dog to the vet before this symptom appears, you should take her now. Other first-stage signs of distemper are a dry cough, diarrhea, and pus blisters on the stomach. The second stage of distemper is even more serious, because the disease can begin to affect the brain and even the spinal cord. A dog in this stage might slobber frequently, shake her head, or act as if she has a bad taste in her mouth. Sometimes she has seizures, causing her to circle, fall down, and kick her feet in the air. Afterward, she seems confused, wandering around and shying away from people.
Unfortunately, when the disease gets this far, there's not much hope for the dog to survive. Dogs who do survive often have permanent neurological (brain and nerve) damage. Distemper can also spread to the lungs, causing pneumonia, conjunctivitis, and inflamed nasal passages (rhinitis); it can also spread to the skin, causing it to thicken, especially on the footpads. This form of distemper is called hardpad disease. Distemper is most likely to strike dogs as puppies between nine to twelve weeks old, especially if they come from an environment with several other dogs (animal shelter, pet store, breeding kennel). If your dog is diagnosed with distemper, your veterinarian will give her intravenous fluids to replace those she's lost, medications to help control the diarrhea and vomiting, and antibiotics to combat secondary infections.
Canine infectious hepatitis. This is a viral disease spread by direct contact. Mild cases last only one or two days, with the dog running a mild fever and having a low white-blood-cell count. Very young puppies -- two to six weeks old -- can suffer a form of the disease that comes on quickly. They have a fever, their tonsils are swollen, and their tummies ache. Very quickly they can go into shock and die. Onset is quick and unexpected: The pup may be fine one day and in shock the next. The most common form of canine infectious hepatitis occurs in puppies when they are six to ten weeks old. They show the usual signs of fever, lack of energy, and enlarged tonsils and lymph nodes. A dog whose immune system responds well will start to recover in four to seven days. In severe cases, however, the virus attacks the walls of the blood vessels and the dog starts bleeding from the mouth, nose, rectum, and urinary tract. If your puppy has canine infectious hepatitis, she will need intravenous fluids, antibiotics, and maybe even a blood transfusion.
Leptospirosis. This bacterial disease is caused by a spirochete, which is a type of bacteria with a slender spiral form. The leptospirosis spirochete is passed in the urine of infected animals and enters a dog's body through an open wound in the skin or when she eats or drinks something contaminated by infectious urine. The signs of leptospirosis are not pretty. Early symptoms include fever, depression, lethargy, and loss of appetite. Usually, leptospirosis attacks the kidneys, so an infected dog may walk all hunched up because her kidneys hurt. As the infection advances, ulcers appear in her mouth and on her tongue, and her tongue has a thick brown coating. It hurts to eat because her mouth is full of sores and might even be bleeding. Her stools have blood in them, and she's very thirsty, so she drinks a lot. To top it all off, she's probably vomiting and has diarrhea.
Treatment of leptospirosis requires hospitalization for a couple of reasons. First, in addition to needing antibiotics to knock out the bacteria and other medications to control the vomiting and diarrhea, a dog with advanced symptoms will have lost a lot of fluid and need to have them replaced. Second, leptospirosis is a zoonotic disease, meaning it can be spread to people. Dogs with leptospirosis must be handled carefully to prevent infection. Even when your dog recovers, she can still be a carrier for up to a year. Your veterinarian can advise you on how to prevent infection after she's well.
Parvovirus. A highly contagious disease, parvovirus can be spread on an infected dog's paws, fur, saliva, and stool. It can also be carried on people's shoes and in crates or bedding used by infected dogs. Puppies younger than five months are hit especially hard by parvovirus and are most likely to die. Doberman Pinchers, Rottweilers, and Pitbulls are especially susceptible to parvovirus. The signs of parvovirus start to appear three to fourteen days after a dog has been exposed to it. Parvovirus can take two forms: The more common form is characterized by severe diarrhea, and the other rare form by damage to the heart muscle.
A dog with parvovirus is literally one sick puppy. If the disease affects her intestines, she'll be severely depressed with vomiting, abdominal pain, high fever, bloody diarrhea and -- not surprisingly -- no appetite. Few diseases cause this wide a range of serious symptoms. When parvo attacks the heart, young pups stop nursing and have trouble breathing. Usually they die quickly, but even if they recover they are likely to have congestive heart failure, which eventually kills them.
Vaccinations are available for parvovirus, but between six weeks and five months of age, pups are especially vulnerable to the disease, even if they've been vaccinated. The reason is complicated. You see, at birth, puppies get their immunities passively, through their mother's milk. Whatever diseases the mom has had or has been vaccinated against, the puppies get protection from, too. The effect of these maternal antibodies fades after weaning but may still be strong enough to interfere with the action of the parvovirus vaccine. With neither type of protection at full strength, the virus can slip in and do its dirty work. Even still, this does not mean you should put off getting a puppy vaccinated against parvo -- two types of protection less-than-full strength is better than only one or none at all.
Parvovirus is hard to kill. The virus can last weeks to months in the environment. If your dog has had parvo, thoroughly disinfect everything she was in contact with, using one part chlorine bleach mixed with 30 parts water.
Rabies. That Harper Lee sure could tell a story. Her description of a dog with rabies in the Pulitzer Prize-winning book To Kill a Mockingbird is not only medically accurate, it conveys all the fear and danger of this dreaded disease. Of course, she was hardly the first to write about it: Rabies has been known for thousands of years and is mentioned in the legal tablets of Mesopotamia and in the writings of Aristotle and Xenophon. Some areas of the world -- notably Australia, Great Britain, Iceland, Japan, and the Scandinavian nations -- have managed to eliminate rabies through strict quarantines on incoming animals, but it is found everywhere else in the world.
The rabies virus is a bullet-shaped killer. It enters the body through an open wound, usually in the saliva delivered during a bite. It can infect -- and kill -- any warm-blooded animal, including human beings. Depending on the area of the country, the wild animals most likely to transmit rabies are raccoons, skunks, bats, and foxes. In 2004, out of a total of 6,844 reported cases of rabies, 94 cases were reported in dogs and 281 cases reported in cats.
Rabies takes two forms. One is described as furious and the other called paralytic. Paralytic rabies is usually the final stage, ending in death. A dog in the furious stage of rabies, which can last for one to seven days, goes through a range of behaviors. She can be restless or nervous, vicious, excitable, and sensitive to light and touch. Her breathing is heavy and fast, causing her to foam at the mouth. Another sign of rabies is a "personality change." For instance, a friendly dog might become withdrawn and snappish, or a shy dog might become much friendlier than usual. As the rabies virus does its work on the central nervous system, the animal has trouble walking and moving. While it's bad form to approach any wild animal or strange dog, never try to approach one who is behaving oddly or having trouble with locomotion. You should be extremely cautious around any animal you know who is acting erratically.
Because rabies is fatal, public health veterinarians recommend euthanizing any animal with signs of rabies who has bitten someone. A dog who appears healthy but has bitten someone must be kept confined for ten days to see if signs of rabies develop. An unvaccinated dog who's exposed to rabies must either be euthanized or strictly confined for six months, with a rabies vaccination given one month before she's released from quarantine. If a vaccinated dog is exposed to rabies, she should be given a booster shot immediately, confined, and closely observed for 90 days. Unfortunately, the only surefire way to confirm a dog has rabies is to examine her brain (specifically, the tissue of her central nervous system) -- which means the dog can't be alive. If you have a dog or cat who dies rather suddenly -- particularly after displaying unusual behavior -- call your veterinarian immediately to see if you should have the animal checked for rabies.
Rabies is serious business. To protect your dog from rabies, you should have her vaccinated when she is three months old, again a year later, and once every three years afterward. If you are bitten by a rabid animal -- or by any animal you can't confirm for certain doesn't have rabies -- immediately clean the bite wound thoroughly with soap and water. Then call your doctor for immediate treatment, which may include a series of rabies vaccinations.
Can I Catch It From My Dog?: Zoonotic Conditions
We can't catch colds from our dogs, but they can share other diseases with us. Conditions that can be spread from dogs to humans are called zoonotic diseases. Some are merely unpleasant, such as the ringworm fungus, but others like salmonella poisoning or rabies can have more serious consequences. Dogs can also pass along leptospirosis, known as Weil's disease in humans, as well as parasites such as scabies, roundworms, tapeworms, hookworms, and the tick-borne Lyme disease and Rocky Mountain spotted fever.
Fortunately, it's not too difficult to prevent Ginger from spreading any diseases to us. She can be vaccinated against leptospirosis and rabies, of course. Worms can be kept under control by picking up her stool regularly and having regular fecal exams and deworming as needed. Good hygiene -- yours, that is -- is one of the most important ways you can prevent zoonosis. So be sure to wash your hands thoroughly after handling the dog or picking up after her. This is especially important to remember for young children, elderly or debilitated people, and people with immune system disorders or undergoing cancer chemotherapy, all of whom are most susceptible to zoonotic diseases.
Ticks. If you live in a wooded or grassy area or take your dog to such places, examine Rover daily for ticks during warm weather. You're most likely to find ticks between her toes or on her head, neck, or ears. Remove ticks with tweezers, grasping them near the tick's head and pulling slowly but firmly. Be careful not to touch the ticks yourself. In fact, it's probably a good idea to wear rubber gloves when you're removing them. Drop ticks in a jar of rubbing alcohol to kill them. Other folk methods -- coating the tick with gasoline or petroleum jelly, or burning it -- are more likely to complicate matters and can actually be very dangerous if the tick bursts or the dog's hair catches fire. However, it can help to spray the dog with a flea-and-tick insecticide before removing the little blood-suckers. Newer tick-control prescription products are very effective at controlling ticks; check with your vet for a prescription.
Lyme disease and Rocky Mountain spotted fever. Lyme disease is spread by the bite of ticks carrying the slender spiraling bacteria called Borrelia burgdorferi spirochete. Ticks carrying Lyme disease include the deer tick in the eastern United States and the western black-legged tick on the West Coast. Ticks come out primarily in the spring and summer, especially when it's rainy, so Lyme disease is most common during the months of May through August, usually reaching a high in July. Most cases are found in the Northeast and mid-Atlantic, but Lyme disease has been reported in most of the lower 48 states.
When dogs get Lyme disease, it usually shows up in the form of arthritis. Suddenly they're lame because their joints are tender and swollen. Not surprisingly, they're listless and weak, don't feel like eating, and may have a fever. In severe cases, Lyme disease can affect the heart, kidneys, and nervous system.
Unfortunately, Lyme disease is difficult to diagnose and is often confused with other diseases. If the dog has been bitten by ticks, develops the signs described above, and then responds to antibiotics, it's a pretty safe bet she was suffering from Lyme disease. If you live in an area where ticks are pretty common, ask your vet for advice on keeping them at bay with flea-and-tick-killing sprays, powders, and collars, or with the Lyme disease vaccine.
Rocky Mountain spotted fever, also spread by contact with ticks, is caused by a different kind of bacteria called a rickettsia, which is rod-shaped and multiplies only within the cells of its host. Wood ticks and American dog ticks are the carriers of Rocky Mountain spotted fever, which is most common in the plains of the Midwest and in the mid-Atlantic states.
A dog with Rocky Mountain spotted fever has -- of course -- a fever, painful joints, and no appetite. In people, Rocky Mountain spotted fever causes flu-like symptoms: fever, chills, achy muscles, nausea, and vomiting. They may be sensitive to light, and a rash develops on their hands, wrists, ankles, and feet, sometimes spreading to the rest of the body. As with Lyme disease, antibiotics are the treatment of choice. Again, the best offense is a good defense: Examine your dog regularly for ticks, remove them carefully when you find them, and use insecticidal products that will kill or repel them.
In the next section, we'll look at early illness warning signs, to help you prevent illness from advancing if it does strike your pet.