The Four Major Dog Diseases

Dogs, like human beings, are susceptible to various bacterial, viral and protozoan diseases. There are four major dog dis­eases that are capable of reaching epidemic proportions and resulting in a high mortality rate. They are distemper, rabies, leptospirosis and canine infectious hepatitis. These diseases are the "Big Four"—the scourges of dogdom. Of the four, dis­temper is the most widespread.

As a dog owner, you should be familiar with these diseases. By knowing the causes, modes of transmission and symptoms, you will be better equipped to help prevent your dog from becoming a victim. There are those who believe the average dog owner doesn't need to know anything about dog diseases, that at the first sign of something wrong, the dog should be rushed to the veterinarian. This is faulty thinking. It assumes that every dog owner can afford to take his dog to the veteri­narian at every itch or burp and that the veterinarians can handle the traffic such a policy would entail. After all, there are about 20,000 veterinarians in the United States and more than 25 million dogs, not to mention millions of cats, birds and other pets. Furthermore, a large percentage of these vet­erinarians are engaged in treating livestock.

In setting down the background of the dog diseases and giving their symptoms, we are not trying to qualify you as a diagnostician or dog doctor. Diagnosing and treating major diseases are in the domain of the veterinarian. But you should have a "working" knowledge of the dog diseases. It's up to you to bring your dog's health problems to the attention of the veterinarian. He's not going to telephone and inquire about your dog's health. He's too busy. You will have to know when to take your dog to him. And to do this you will have to know how to recognize the difference between serious and minor conditions. A knowledge of dog diseases will help you make that distinction.

Finally, there's the matter of your being an informed dog owner. Today, Americans have a much better knowledge of their general health, diseases and treatments. They have ac­quired this knowledge by reading books and magazines, watching television and listening to the radio. You, as a dog owner, should become informed about your dog's health and what can be done for him if he should contract a serious dis­ease. If your dog should become a victim of a major disease, you will have a large part in nursing him back to health. A working knowledge of the diseases will help you to under­stand the treatment and the dog's chances of recovery. It will also enable you to assist the veterinarian.

DISTEMPER

Despite the tremendous amount of research being done on distemper, it still continues to be a major dog killer. It is an acute, highly infectious disease caused by a virus. Young dogs, especially puppies, are the most frequent and numerous vic­tims. Nursing puppies, however, are rarely affected, since a certain degree of immunity is passed to them from their mother by way of colostrum-milk. But to get this natural immunity, the pups must partake of the colostrum-milk dur­ing the first 8 to 24 hours of life.

While distemper is basically a puppy and young dog disease, older dogs can become victims. This is particularly true of those older dogs that have led sheltered lives, with little or no opportunity to become exposed to the virus and build up an immunity. The writer has seen dogs 7 and 8 years old with distemper.

The distemper virus is known as the virus of Carré. It is an airborne virus; that is, it is transmitted chiefly through the air. But it can also be transmitted by direct contact with the saliva, urine, feces or nasal discharge from an infected dog. Human beings are often unwitting carriers of the distemper virus, bringing it home on their hands, shoes and clothing.

The incidence of distemper has seasonal peaks, with the disease reaching its most virulent form in the early spring, fall and winter. Warm weather has an adverse effect on the distemper virus, forcing it to become dormant. The preva­lence of distemper is at its lowest point during summer. The incubation period for distemper ranges from 3 to 21 days or longer. It is a very serious disease and one that requires prompt attention.

Basically, distemper is a disease of the epithelial tissues. All of the visible mucous membranes—mouth, gums, nostrils, etc.—become inflamed as the virus intrenches itself. The dis­temper virus is the vanguard for secondary bacterial invaders. After the virus has set the stage, bacteria move in and cause such symptoms as tonsilitis, diarrhea, pneumonia and skin eruptions. The chief bacterial invaders are members of the staphylococci, streptococci and brucella groups. It is this combination of bacteria and virus that makes distemper so difficult to treat.

One of the earliest symptoms of distemper is what we might call general cold symptoms: running nose, weeping eyes, sneezing, a dry, hacking cough, poor appetite and diar­rhea. The dog's temperature will fluctuate between 1030 and 104°F. All of these symptoms become worse as the disease progresses.

The failure to start treatment when these early symptoms appear contributes toward a high mortality rate for this dreaded dog disease. Too many dog owners dismiss the early symptoms as "just a cold" and are later stunned when told the dog has distemper. Granted, recovery from distemper is the exception rather than the rule, but some dogs have re­covered when promptly treated.

As the virus and bacteria continue their devastation, the dog becomes more and more emaciated and dehydrated. The discharge from the eyes and nose changes from a colorless fluid to a thick, ropey and often bloody discharge. When the discharge dries on the nose or eyes, it cakes and interferes with breathing and vision. The dog has an increased thirst and will try to drink great quantities of water. His bowel movement changes from a soft stool to a watery or bloody movement, with a highly objectionable odor. He may vomit and go into fits or convulsions, with muscular twitching or champing of the jaws. Eventually, the dog succumbs from an overwhelming infection.

The distemper story is not a pleasant one. It's rather grim and dismal. Your dog's chances, once he's contracted the dis­ease, are very slim. There is no specific cure; the best that can be done is to treat the various symptoms. Those dogs that do recover are usually left with nervous disorders, such as tics or chorea.

Immunization

Fortunately, your dog can be immunized against distem­per. The veterinary profession has made great strides in the immunization of dogs against distemper, as well as hepatitis, rabies and leptospirosis. But it must be made clear now that there is no such thing as a permanent inoculation. A few years ago, veterinarians gave a series of injections against distemper and called the final shot "permanent." We know today that no inoculation can be considered permanent. Some types of inoculation are just more lasting or durable than others.

Before we discuss an immunization program for your dog, let's see how the distemper immunization theory is supposed to work. First of all, as stated before, newborn puppies re­ceive varying degrees of immunity in the form of antibodies in the colostrum-milk. Tests taken on puppies 48 hours after birth at the Cornell Virus Research Institute reveal that the pups have the same level of immunity as their mother. Like­wise, if the mother is not immune, the pups will not be im­mune. It was also found that immunity was passed from the mother to the pups during the first 8 hours of life. No im­munity was passed after the pups were one day old. The point to remember here is that every pup should get colostrum-milk during the first 8 hours of his life. The immunity passed through the colostrum-milk can last from 1 to 3 weeks up to as long as 3 or 4 months.

On the other hand, while the immunity passed through the colostrum-milk is vital to the protection of the nursing pup, it presents some problems after the pup is weaned. Drs. James A. Baker and James Gillespie of the Cornell Virus Re­search Institute found that natural immunity passed by the mother later interfered with the vaccination of the weaned pups. Those puppies with natural immunity simply could not be vaccinated. In other words, the natural antibodies pre­vented an immune response in vaccinated pups.

This was an important discovery. Prior to it, veterinar­ians customarily gave puppies injections of distemper serum spaced 10 to 14 days apart until the pup was 9 to 12 weeks of age. After this, the puppy was given an injection of dis­temper vaccine, the so-called "permanent shot." Yet, despite this prophylaxis, many pups came down with distemper. The veterinarians gave reasons for these distemper "breaks." The pups probably were exposed to the disease before being vac­cinated, they were in a poor state of nutrition and had intes­tinal parasites. In many cases, this was true. But in others, no. Hindsight, of course, shows us that many of these distem­per "breaks" could be ascribed to the presence of natural antibodies that interfered with the vaccination. Drs. Baker and Gillespie further learned that puppies with natural immunity passed along to them from the mother could not be artificially infected with distemper. In short, they just could not get distemper until their natural im­munity wore off and they were ready to catch the disease.

Working from this basis, Dr. Gillespie developed a test whereby the degree or level of immunity passed from the mother to the pup could be determined. By blood-testing the mother during pregnancy and using a chart called the Nomo­graph, it is now possible to tell how much immunity a pup will inherit. It is also possible to predict when the pup will lose that natural immunity. The blood test can be used for dogs of any age and will show the state of their immunity. It is easy to see the great value of such a test. There is no longer any need for guesswork or hit-or-miss immunizations.

The blood test tells us when a puppy is "ripe" for vaccina­tion or an older dog for revaccination. The next considera­tion is the quality of distemper vaccines. The scientists at the Cornell Virus Research Institute conducted a qualitative and quantitative analysis of the various vaccines. They concluded that an attenuated live-virus vaccine of egg origin was the most efficient. An attenuated live-virus vaccine is one that has had its virulence reduced. The egg origin part means the virus was propagated in a fertile egg. A killed-tissue vaccine is one in which the virus has been grown on tissue such as pig kidney, then killed.

Drs. Baker and Gillespie used the attenuated live-virus vac­cine of egg origin for three good reasons. One, it cannot pro­duce distemper, two, it can produce long-lasting immunity and three, it can be standardized. All of these factors are im­portant in the successful immunization of dogs. The matter of standardizing vaccines has been a troublesome problem. Too many vaccines were not standardized and varied from batch to batch as to quality and number of antibodies in a given quantity.

The attenuated live-virus vaccine developed at the Institute was highly successful in tests on puppies in the Institute's laboratory. Ninety-eight per cent of the disease-free pups in the laboratory became immune when vaccinated. But when used in the field or on the general run of dogs, the vaccine was only 75% effective. Here was another problem. Why the lower percentage of immunization in the average dog?

The answer turned out to be that the average dog is not as ideal for vaccinating as dogs reared in special disease-free lab­oratories. Test puppies go through all kinds of checkups and are sheltered from disease. The average dog is an unknown quantity and is exposed to all kinds of infections. Among the factors that prevent a higher percentage of successful vacci­nations are 1) exposure to distemper before vaccination; 2) poor state of nutrition; 3) infestations of parasites; and 4) a high number of natural antibodies when vaccinated.

Now let's translate all of this research data into a practical immunization program for your dog. We'll start when you get your pup. The kennel or pet shop owners will probably tell you that your puppy has had his "puppy shots" and needs a final injection. Or they may tell you the pup has had all of his distemper shots. First, forget about the term "final shot." Next, unless the seller certifies that the pup has immunity as shown by a blood test, start from scratch. You have no assur­ance (in the absence of a blood test) that the pup is immune just because he got some serum and a vaccine shot before you bought him. Remember that both natural immunity passed by the mother and antibodies built up by distemper serum can interfere with the vaccine. This conceivably could have happened to your pup. Play it safe: take him to the veteri­narian and have him revaccinated with a live-virus vaccine. Then, one month later, have a blood test done to determine if the vaccination was successful.

Since we now know that no vaccine—whether it is a live-virus or killed-tissue vaccine—confers permanent immunity, your dog should have either an annual blood test to determine his immunity level or a routine yearly booster shot. If the blood test shows the dog to have a titer below 100, he should be revaccinated. It is wise to keep in mind that booster shots for dogs with high immunity are a waste of money, since booster shots will not raise the dog's level of immunity.

At the present time, distemper immunization is not stand­ardized. Some veterinarians use the killed-tissue vaccine (the same situation is true for polio), while others prefer the at­tenuated live-virus vaccine recommended by the Cornell Virus Research Institute. Furthermore, some veterinarians use serum shots until the pup is 9 weeks old, then inject either a live-virus or killed-tissue vaccine.

As we pointed out, serum interferes with the success of vaccine. Since they cannot tell just when the antibodies cre­ated by distemper serum disappear, those veterinarians using serum hold off with the vaccine for 14 or 15 days. They hope the serum antibodies will have gone by this time. But with­out a blood test, nobody can be sure just when the antibodies go. If they go before the 14 or 15 days are up, your dog is exposed to distemper until he gets the vaccine. If the serum antibodies remain beyond the 14 or 15 days and the pup gets a vaccine shot on the 14th or 15th day, the chances are it will not be successful. At any rate, this system is not without risk.

Quite possibly, your veterinarian follows this serum and vaccine procedure. While we recommend immunization with an attenuated live-virus vaccine (no serum), followed by a blood test one month later, we realize you may have no choice. We suggest a compromise: if your veterinarian uses the serum shots and vaccine system, have your dog so inoculated. But insist upon a blood test approximately one month later. It is unlikely that any veterinarian will dispute the value of the blood test to determine if the vaccination was successful. The efficacy of any type vaccine—killed tissue or live virus-can and should be determined by a blood test one month after vaccination. Do not back down on this point. It will save you grief and possibly your dog's life.

RABIES

First, it should be pointed out that rabies is a relatively rare dog disease. Very few veterinarians or dog breeders have ever seen a case of rabies. Yet no other disease of man or ani­mal has been surrounded with as much superstition, fear or fiction as rabies. It is one of the oldest diseases, dating back to several centuries before Christ. Rabies is basically a dis­ease of canines; i.e., the domestic dog, coyote, wolf, dingo, and pariah dog. But it is transmissible to other animals, in­cluding man, squirrel, fox, skunk, rabbit, mink, horse, cow; even the bat. Some birds are susceptible to the disease. How­ever, the chief victims are members of the dog family. And since the dog lives close to man, the disease assumes a posi­tion of great importance.

Rabies is caused by a virus that affects the central nervous system. The virus is found in the saliva of infected animals. The method of transmission is through the bite of a rabid animal. When a person or animal is bitten by a rabid animal, the saliva containing the rabies virus is passed into the bite wounds. The incubation period for rabies ranges from two weeks to several months, with the average time at thirty to sixty days. The important fact to remember is that a person or animal must be bitten by a rabid animal before there is any danger of contracting the disease.

Not every person bitten by a rabid animal necessarily con­tracts rabies. According to the United States Bureau of Ani­mal Industry, Pathological Division, approximately 15 per cent of all human beings and 35 per cent of all animals bitten by rabid animals contract rabies. Several factors determine whether a bite victim will become infected. Since the rabies virus attacks the central nervous system, it follows that the closer the bite to that system, the greater the danger. Bites on the hands, face or neck are the most dangerous from this standpoint. The depth of the bite is also an important factor; the deeper the bite, the greater the chances of contracting rabies when bitten by a rabid animal. Finally, the amount of bleeding from the bite wounds must also be considered. If the bite wounds bleed profusely, the rabies virus may be washed out. But this chance should not be taken and all wounds should receive prompt medical attention.

Generally, the symptoms of rabies are complex and only a close observation of a suspected animal can determine if the animal is rabid. The only positive test is a microscopic exam­ination of the dog's brain. When the rabies virus attacks the brain it causes the formation of what are known as "Negri" bodies. These are visible under a microscope and are positive signs of rabies.

One of the first rabies symptoms to appear is a very notice­able change in the dog's behavior. A friendly dog may become irritable, snappy, or ferocious. Or the opposite may occur: a snappy, surly dog may become docile and dull. However, most rabid dogs are very restless and easily excited. The only positive case of rabies observed by the writer was a dog that would fly into fierce rages when a stick was thrust at him through the cage door. The dog had been confined as a suspected case of rabies after having bitten three people and another dog. He became increasingly worse and died four days after being confined. A microscopic examination of his brain revealed the Negri bodies that are associated with rabies. This is the only case of proven rabies seen by the writer in more than twenty years of experience with dogs. The rarity of the disease, however, does not lessen its danger.

There are two forms of rabies: 1) a highly excitable, raging type, in which the dog runs amok, snapping and biting any person or animal in its path, and 2) a dumb type, in which the dog appears to be stunned or in a state of shock. In the dumb form of rabies the dog shows no inclination to roam or bite. A classical symptom of the dumb form of rabies is what may be called "fallen jaw." The dog's mouth hangs open several inches. Now, any dog that has something stuck in his mouth or throat will usually open his mouth. But if an obstruction is the main trouble, the dog will paw and scratch at his mouth. In the case of "fallen jaw" associated with ra­bies, the dog makes no attempt to dislodge anything or paw at his mouth. He just sits staring, with his mouth hanging open.
Other symptoms of rabies are convulsions, foaming at the mouth, a change in the voice pitch and paralysis of the throat muscles. The rabid animal becomes very thirsty, but because of the throat paralysis, cannot drink water or other liquids. This inability to drink has given rise to the erroneous name of hydrophobia—a fear of water. It is not a fear of water, it is an inability to drink water.

There is no known cure for rabies, either in human beings or animals. If you suspect rabies, do not touch the dog. While there is no need to get panicked just because your dog has a fit or foams at the mouth, it is wise to proceed with cau­tion. Call your veterinarian, police, board of health or local humane society.

If you are bitten by a strange dog, here is the procedure to follow: get the name and address of the dog's owner or a description of the dog. Next, thoroughly wash the wounds with soap and warm water, making sure that you work the soap down into the bites. Tincture of green soap is best. Work up a good lather and keep it in the wounds for at least 20 or 30 minutes. This is no guarantee that you won't con­tract rabies if the dog was rabid, but it may help. Have the wounds treated by a doctor. Under the law, he must report treating dog bites. When a dog bite is reported to the author­ities, the usual procedure is to confine and isolate the offend­ing dog. The dog is observed for a period ranging from 10 to 14 days. Rabies works quickly on the dog; if he is still alive and his general behavior and symptoms improve after the observation period, he didn't have rabies. If the dog dies during the confinement period, his head is sent to a diagnos­tic laboratory where the brain is examined for Negri bodies.

It's to your advantage to have the offending dog confined, otherwise you will be subjected to a series of anti-rabies in­jections. If you were bitten by a stray dog, try to give as com­plete a description as possible. Circulate the description around—to the newspaper, radio station and any other public communication source. Ask friends and neighbors to be on the lookout for the stray dog.

If your dog bites someone, see that the victim receives prompt medical treatment. Next, report the bite to the police or board of health and surrender your dog for observation. Don't argue about it. Someone's life may be at stake. Give complete information as to rabies vaccination.

Immunization

Your dog can be immunized against rabies. Usually the rabies vaccination is given when the dog is six months old, since the disease affects mostly older dogs. Currently, two types of rabies vaccinations are given: one type of vaccine con­fers immunity for one year, the other type confers immunity for three years. Consult your veterinarian as to a rabies vac­cination for your dog. If your dog receives the vaccine good for one year, see to it that he gets a yearly shot.

INFECTIOUS CANINE HEPATITIS

Not too long ago, infectious canine hepatitis was confused with distemper or at least considered to be part of what many veterinarians called the "distemper complex." Today, hepa­titis is considered to be a separate disease.

Canine hepatitis is another virus disease. The virus is spread by direct contact with the nasal discharge, saliva or urine of an infected animal. Affecting the liver and usually running a short course of a few days, hepatitis can be fatal if treatment is delayed. The canine hepatitis virus is not the same one that infects human beings.

Hepatitis has distemper-like symptoms, especially in the early stages of the disease. Listlessness, inflamed tonsils, increased thirst, discharge from the nose, diarrhea and vomiting are all symptoms of hepatitis and distemper. Unlike distem­per, the dog usually has a high temperature, above 104°F. There is also abdominal tenderness, blood in the vomit or stool, and inflammation of the inner surface of the eyelids and front part of the eyeballs. An opacity or bluing of the eyes may also be present, although this is usually present after the acute stage of the disease has subsided.

The hepatitis virus gains entry into the dog's gastrointes­tinal tract when the dog comes into contact with or ingests infected matter or comes into contact with urine or saliva from an infected dog. It has been shown that the hepatitis virus remains in the urine for as long as six or more months after a dog has recovered from the disease. If your dog has hepatitis symptoms, see that he gets prompt veterinary at­tention.

Immunization

Your dog can be immunized against canine hepatitis. Most veterinarians give a combination injection of distemper and hepatitis vaccine. The blood test developed by Dr. Gillespie can be used to determine the level of immunity against hepa­titis. Consult your veterinarian for hepatitis vaccination.

LEPTOSPIROSIS

The last of the "Big Four" is leptospirosis, a bacterial dis­ease of dogs, human beings and other animals. It occurs in two forms: 1) canicola fever, and 2) Weil's disease. Both types are transmissible from animals to man. The organisms caus­ing leptospirosis belong to the spirochete group of bacteria.

Leptospirosis affects the kidneys and liver. It is marked by a yellowish discoloration of the dog's skin and mucous mem­branes (gums, palate, nostrils, etc.). Distemper-like symptoms appear in the early stages. These are weakness, no appetite, vomiting, increased thirst, nasal discharge and general emaciation. The temperature rises to 103° to 105° the first day, then drops sharply to as low as 97°F. the next day. There is also muscular stiffness, especially the hind legs; a heavy, dark urine; abdominal pain; a watery and bloody bowel movement; and jaundice. Leptospirosis requires immediate veterinary attention.

Rats are known carriers of the organism causing leptospiro­sis and the flea, louse, tick and fly are suspected as being car­riers. The mosquito is also suspect. Your prevention program should include the elimination of fleas, lice and ticks from the dog. Insect and rodent control should be practiced, both for human and animal protection. Since rats often get into dog food and other supplies, discard any stale or loose dog food. Avoid damaged packages of dog food in the food stores.

Immunization

Leptospirosis vaccine is available. It is important to keep in mind that while the leptospirosis vaccine affords long-lasting protection, it will not last for the dog's lifetime. You will be wise to have the dog revaccinated from time to time, especially if there is an outbreak of leptospirosis in the neigh­borhood.

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