Canine Herpes Virus
Ron Hines DVM PhD
Lots of my articles are plagiarized and altered on the web to market products and services. There are never ads running or anything for sale with my real articles. Try to stay with the ones with http://www.2ndchance.info/ in the URL box or find all my articles at ACC.htm.
What is Canine Herpes Virus?
Canine herpes virus (CHV-1) affects only dogs. In mature dogs and puppies over 3-4 weeks of age, this virus causes a mild respiratory disease that dogs overcome rapidly. But like all the herpes viruses of man and animals, all recovered dogs carry a few of the virus for life in a sleeping or latent form. But if your dog is one of the many that carries this virus, it could become a serious problem again in your dog's puppies.
Canine herpes virus is very common. It is found all over the World. Approximately one out of two or one out of three dogs have been exposed and carry this virus in their bodies. The greater the number of dogs that are kept together or that live in close proximity, the more likely the virus is to be present. The more stressed breeding bitches are exposed to, the more likely herpes-related puppy loss and small or lost litters will occur. In some kennels, 100% of the dogs show evidence that they harbor CHV-1.
Although it is theoretically possible to establish groups of herpes-free dogs, show kennels and large breeding kennels can not avoid this virus. However, good kennel practices, avoidance of too-frequent breeding , good sanitation and proper nutrition will help you minimize or eliminate potential CHV-1 problems.
How Is Canine Herpes Virus Spread To My Dog ?
Most dogs become infected with canine herpes virus by inhaling or sniffing virus- containing sneezes and any liquid or moist secretions from an infected, virus-shedding dog. This can be another dog that was recently infected at a dog show or kennel or a carrier dog that relapsed due to a stressful situation. Most of the dogs that are passing on this virus appear completely normal.
A stud can transmit canine herpes virus to your bitch or vice versa. When a stud is shedding, the virus is present in his semen. When a bitch is shedding, the virus is present in her vaginal secretions. But this is not the primary way the disease moves around.
Canine herpes virus does not last long in the environment. So just passing your dog through an area that has CHV-1 positive dogs is not a problem. Sunlight, common disinfectants and bleach kill the virus rapidly.
How Will Canine Herpes Virus Affect My Puppies?
If you are a breeder, the most likely thing you will see subsequent to a CHV-1 problem is a drop in fertility in your breeding bitches. If you are the owner of a single female, the most likely thing to happen is a tie with no puppies at whelping time.
But if your bitch experiences a rise in virus numbers near the end of her pregnancy without a sufficient rise in her antibody level, you will loose all or some of the puppies during their first three weeks of life. This can be your bitches first experience with the CHV-1 virus, or a relapse due to the stress of pregnancy and other factors - usually the latter.
Most of these lost puppies are infected by their mothers during birthing or shortly thereafter. But some develop the infection while still in the womb. When infection occurs while the puppies are still in her uterus, they may be stillborn, re-absorbed or aborted before they reach term.
When a puppy under 3-4 weeks of age becomes infected with this virus, the disease takes an entirely different course than it does in an older dog. We believe this is because puppies up to 3-4 weeks old do not regulate their body temperature well and because the immune systems of these puppies are not sufficiently developed yet. Puppies born from mothers that have a decent antibody level against herpes are protected through this critical period. But herpes viruses are notorious for not stimulate good immunity. If the mother dog has adequate immunity herself, she will pass it along in her first milk (colostrum) in the form of anti-herpes antibody and immune cells that protect her puppies.
Infected, susceptible puppies usually die within their first 3 weeks. But their mothers continue to look fine. If some puppies survive, they are often poor doers that suffer from multiple health problems including heart and nerve damage.
What Are The Signs That My Breeding Dog(s) Might Have Herpes Virus?
Lack of breeding success and star-crossed puppies are the most common signs of a canine herpes virus problem. Late term abortions or re-absorption of the puppies is also common. The most common hint of the presence of CHV-1 in your adult animals are transient, mild, upper respiratory problems. Less commonly, ulcers similar to cold sores and inflammation occur on the animal's vagina, or on the prepuce and base of the penis. Problem periods often follow an increase in dog numbers or changes in your husbandry practices.
But the majority of dogs dealing with canine herpes virus show absolutely no signs that they are sick.
Only isolation of individual dogs and carefully-considered matings will shield your animals from CHV-1. As with their wide-spread cousin, the human cold sore virus, the presence of CHV-1 in your kennel is very likely. But it is certainly not a tragedy for your kennel or hopes of successful breeding program either.
What Are The Signs Of Canine Herpes Virus In My Puppies ?
Your puppy could have been infected any time from late pregnancy through the first three weeks after birth. Whenever it occurred, it takes 3-7 days from the time the virus first entered the puppy for it to begin its destruction.
If the puppies were born alive, the first sign of infection is often a lack of interest in nursing. But there is no one, specific, sign that alerts us to herpes. The puppies just aren't doing well. They may whine continuously and appear uncomfortable. They may appear to be in pain due to tender tummies. They often have fast, shallow breathing. They may vomit. They may pass yellowish green stools. Nose and eye discharges are common. Less common signs are an increased tendency to bleed and seizures. Infected puppies sometimes have pin-point hemorrhages on their gums.
Young puppies, are not capable of running a fever. Their body mass is just not large enough in proportion to their skin area. This is the weakness of puppies in dealing with herpes. The virus reproduces much more rapidly at the puppy's lower body temperature than in dogs that can mount a fever.
As the disease progresses, the puppy’s temperature drops to subnormal (Below 98F, 36.7C). Subnormal temperature in puppies is a grave sign. The disease progresses very rapidly and the puppies usually die in 1-3 days. Because the signs are few and the disease rapid, owners may not recognize that their puppy is ill until it is gone. If the puppies are lost during their first week, they were probably infected while still in the womb.
By the time the puppy is three weeks old, its defenses and temperature regulation are better and it will usually not die from CHV-1.
Exact outcomes vary - not every puppy in a litter with this problem may die nor will they all necessarily have the virus.
How Is Canine Herpes Virus Diagnosed?
The blood tests we currently have are not very helpful identifying dogs that carry the canine herpes virus or in managing the ones that do. They are also not helpful in identifying which mothers will have problem litters. If a dog has a titer to CHV-1 , we know the bitch or stud is infected. But we don't know if the dog is, or will be, shedding virus during or after pregnancy. If the antibody test is negative, we are not certain the dog still does not have the virus lurking somewhere it it's body. This is because the virus doesn't stimulate long-lasting antibodies.
To tell if your dog is shedding the virus, blood samples need to be collected two weeks apart. If the antibody level in the second sample is 3-4 times as high as in the first sample, the dog is likely in a virus-shedding period and should not be bred. However, a steady, low antibody level or no antibody at all is no guarantee that a female that carries CHV-1 will not begin to shed virus during or after her pregnancy.
When canine herpes virus is suspected in the death of puppies, the puppy's remains need to be refrigerated immediately , packed in ice, and sent to a veterinary diagnostic laboratory. The remains should not be frozen. This submission must be done through your veterinarian. If you live outside of the United States or too far to send refrigerated samples, tissues can be collected from the puppy with the instructions of a trained technician , preserved in formol and shipped by ordinary mail.
The pathologist who examines this tissue will look for certain things that are characteristic of herpes virus infection. The most important is evidence of extensive bleeding (hemorrhage) in the liver, lungs and kidneys. This occurs because the herpes virus destroys the puppy's blood-clotting platelets. Damage and bleeding into the spleen, lymph nodes and adrenal glands are also characteristic of puppy death due to herpes virus as are fluid leakage into the chest and abdominal cavities.
If recently aborted fetuses are submitted, they should be handled like puppies and , if necessary, tested with the same techniques used on swabs obtained from adults.
Is There Any Effective Treatment?
Adults and Juvenile Dogs Over 3-4 Weeks Of Age:
Rest and TLC are all adult dogs need to get over the active stage of herpes infection or relapses.
Puppies Under 3 Weeks Of Age:
Treatment of sick puppies that have this disease is not successful. Since your veterinarian is not certain yet that this is a case of herpes virus, he/she will probably try all sorts of life-supporting measures including warmth, tube feeding, oxygen and intravenous or subcutaneous fluids. Pups tend to perk up a bit with this care - but they fade back down shortly thereafter.
Although elevated temperature kills this herpes virus, treating the puppy with elevated temperature has not proved effective in saving the pups.
There are reported cases where puppies were saved by giving them blood serum from adult dogs that recently recovered from herpes virus. Blood serum from these adult dogs often contains enough antibodies to neutralize the herpes. If you have a herpes virus problem in your kennel and want to protect certain puppies during their first three weeks of life, 1-2ml of serum may do so. This serum can be frozen at -4F (-20C) in 1-2ml amounts. At this temperature, it lasts indefinitely. Antibodies will be highest in mature dogs that have just recovered from an active relapse or initial infection. It would be excellent if this serum was tested and found to be PCR-herpes negative with an anti-herpes antibody titer of as high as 1:1024 - but 1:64 or 1:32 would probably do.
There is another report that the antiviral drug, vidarabine, has saved some puppies. I do not suggest you treat sick puppies. When puppies survive herpes virus infection they are usually left with nervous system and heart damage and it is kinder to just let them pass on.
Are There Any Other Diseases That Could Be Mistaken For Canine Herpes Virus?
There are a few common infectious diseases that can be mistaken for herpes deaths in puppies. Canine brucellosis and overwhelming bacterial infections (septicemia) are two that need to be ruled out.
Accidents and inexperienced or distracted moms are also a common cause of puppy death. Also, some puppies have birth defects that lead to sudden early death.
More rarely, the protozoan parasites, Neospora and Toxoplasma cause sudden puppy death. Fatal puppy infections with the canine adenovirus, corona virus and the MVC virus have also been encountered but this is rare.
How Did My Dog Catch Canine Herpes Virus?
Most likely, your dog was exposed to the herpes virus at a kennel, groomer, dog show or animal shelter - any place where large numbers of dogs gather at one time. It did not catch the virus from just passing through these areas - it sniffed or inhaled secretions from another infected dog.
Although it is possible that your dog contracted the virus while being bred, or artificially inseminated, that is not the way most cases occur.
Is There Any Cure For Canine Herpes Virus In Adult Dogs?
Once a dog catches canine herpes virus, they are never completely free of it again. Most dogs that become infected, go through a mild initial upper respiratory tract illness that lasts a week or two and then are never visibly sick again. But the CHV-1 virus is very well adapted to dogs. Instead of being completely destroyed by your dog's immune system, some of the virus enter cells within the pet's nerve centers (trigeminal & lumbosacral ganglia, etc.) and live there in a state of suspended animation forever. In this state, they do no harm. In this state, the dog can not spread the disease. In this state, all laboratory tests for the presence of the virus or antibody against it may be negative. But the virus is still there. And, in a few dogs, it will reappear in its infective state when the dog's immune system is stressed.
If you would like to understand this phenomenon better, read about how herpes simplex viruses (HSV-1 & 2) affect humans. The human and the dog herpes viruses are very similar in how they behave once they have gained access to the body. However, many more resources have been invested in understanding the human herpes virus than the dog herpes virus.
What About Vaccination?
The Merial Pharmaceutical Company has developed a vaccine that boosts immunity to canine herpes virus for about 60 days and makes it less likely that a bitch will be shedding virus during pregnancy, delivery and nursing. It also makes it more likely that the bitch will pass on her herpes-immunity to her puppies through her first milk (colostrum). This vaccine is called Eurican Herpes 205. It appears to be quite effective. However, although it is available in Europe and pehaps elsewhere, is not yet marketed in the United States.
The first injection is given when the bitch is bred. The second is given 6-7 weeks later. The process must be repeated every time the dog is bred since the immunity it gives is temporary. It is a good insurance in first-time breeders and repeat problem breeders.
Breeders have asked me when this vaccine will be available in the US. I have not been successful in obtaining this information from Merial. The policy of this Georgia-based company is to release as little information as possible as to their marketing plans. The only person I know of that could answer this question is Dr. Herve Poulet, the veterinarian who developed it.
How Can I Sanitize Against The Virus?
Herpes is not a tough virus like parvo. Canine herpes virus is quickly killed by most common household disinfectants. Temperature over 104 F kills the virus as does exposure to bright sunlight.
At dog shows and other community areas with many dogs, keep paper towels and a spray bottle of dilute antiseptic close at hand. Disinfect your hands before touching other dogs or allowing your dog to be handled by others. Good disinfectants for herpes, listed in order of effectiveness are 70% isopropyl alcohol mixed 50-50 with water, 0.5% Lysol, Listerine mixed 50-50 with water and household bleach diluted 7 tablespoons-full in 1 quart of water (2000ppm).
Keep your dog on a short lead. Keep its head up and do not let it sniff the floor and objects. Spray and wipe off it paws with alcohol.
Do not share items, food or water between dogs. Spray and wipe down kennels before between animals. Keep your dogs as isolated from other dogs as possible.
How Can I Prevent Another Litter of Sick Puppies ?
The most common scenario is that bitches that loose a litter to canine herpes virus go on to deliver normal litters. This is because these females eventually clear their bloodstream of virus leaving only the non-infective, dormant virus in portions of their nervous system. When this does not happen, the bitch's general health needs to be examined for things that are interfering with her immune system. This could be chronic, stressful environment, poor nutrition, crowding, poor sanitation, or a chronic disease of some other type. Shipping and boarding can also be enough to relapse these dogs.
The thyroid hormone level (T-4) needs to be determined in older (5yrs+) breeders. There is mixed info on whether corticosteroid drugs play a part in relapse.
Isolation and quarantine of bitches from three weeks before they are bred until three weeks after they are bred can be helpful. Given their own private setting, individual care, and TLC, they are less likely to start shedding the virus again. If they are still free of the virus at breeding age, they will more likely stay that way when they are isolated.
When the puppies arrive, maintain them in clean, warm, well-ventilated areas away from the other dogs. Maintain a routine de worming and external parasite program.
Do not over-breed your bitches.
Should I Breed My Female Dog Again?
If there were good reasons for you to breed your dog before you learned that it harbored the CHV-1 virus, there is no reason not to breed her again. Wait a year, build your dog's health up and breed her again to a different stud.
If the second litter is still a problem litter, retire the breeder.