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 103 0 and 104°F. All of these symptoms become worse as the disease progresses.

The failure to start treatment when these early symptom 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.

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