Vaccinations

Vaccinations

by Madalyn Ward, DVM

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My experience has been I see more chronic disease in heavily vaccinated horses. I would like to explain why I think this occurs. First, one must understand how vaccinations work. The 1 to 2 cc of vaccine injected into the horse does not provide protection from disease. This is very important to understand. It is the response of the horse's immune system to the vaccine that determines whether or not the horse will be protected.
The vaccine is an antigen designed to trigger a specific antibody reaction so the next time the immune system sees this antigen it will react quickly to combat it. This sounds like a great plan and has the potential to work with a good quality vaccine and a strong healthy immune system. The problem is many diseases don't produce good antigens and toxic substances called adjutants must be added to trigger reaction by the immune system. Also, the immunity following many vaccines is very short requiring injections to be given as often as every 2 months.

Would you allow yourself to be vaccinated every 2 months? I would like to make an analogy of the havoc multiple vaccines can cause. Consider the body as a country and the immune system as the army and local police in charge of protecting it. The nervous system acts as the communication network and the circulatory system makes up the highways. The army regularly protects the borders and the police keep internal peace. Everything goes well until without warning there is a huge invasion of enemy paratroopers. (Say you vaccinate your horse for VEW-T, Flu, Rhino, Rabies, Strangles, and Potomac Horse Fever on the same day) These invaders use our established highway system to infiltrate all areas of our country. Now if we have a very strong army and police force, the invasion will be thwarted. However, border patrol and local peace keeping efforts may suffer temporally. This is why it is important to give your horse several days vacation after any vaccine.

If, however, your horse has a marginal or weak immune system, a whole different scenario may occur. Because there are no reserve soldiers all forces are withdrawn from their regular duties to fight the invasion. Communications may break down as chaos develops. (Chronic Herpes) In the confusion orders may be given to attack friendly forces (Auto Immune Disease such as Periodic Ophthalmia) Stressed soldiers may become trigger happy and shoot at anything they see (Allergies) or roads may be blocked in a attempt to pin down the enemy, but at the same time cutting off vital supplies to the country side. (Laminitis) Even if the war is won, it is often at great expense as criminals have taken over many cities while the police were preoccupied. (Cancer) Remember, even though this is just a vaccine, it is designed to trick the immune system into thinking it is the real disease. With natural infection there would never be more than one disease at a time. It is critical that the status of the immune system and the risk of exposure be considered before any vaccines are given.
Typical Vaccination History
Apr 1989 Potomac Horse Fever
May 1989 Potomac Horse Fever
Aug 1989 Flu,Rhino
Nov 1989 VEW-T, Flu, Rhino, Rabies, Strangles
Dec 1989 Flu, Rhino
Apr 1989 Flu, Rhino
Aug 1990 Flu, Rhino
Dec 1990 VEW-T
Jan 1991 Flu, Rhino
Oct 1991 Flu, Rhino
Feb 1992 VEW-T, Rabies, Strangles, Potomac Horse Fever
Jul 1992 Flu, Rhino
Dec 1992 Flu, Rhino, Strangles
May 1993 VEW-T, Rabies, Potomac Horse Fever
Jun 1993 Flu, Rhino, Strangles
Aug 1993 Remove Melanomas Surgically
Sep 1993 Flu, Rhino
Mar 1994 Flu, Rhino
May 1994 VEW-T, Rabies, Potomac Horse Fever
Jul 1994 Laminitis
Sep 1994 Laminitis
Dec 1994 Flu, Rhino - Horse still under treatment for Laminitis
Mar 1995 Flu, Rhino
May 1996 VEW-T, Flu, Rhino, Rabies, Strangles, Potomac Horse Fever
Aug 1996 Colic
Jan 1997 VEW-T, Flu, Rhino, Rabies Strangles, Potomac Horse Fever
July 1997 Return of Melanomas Severe Laminitis Silicea
Pure flint - Silicea is indicated in ailments secondary to detective nutrition. It will often help with the assimilation of minerals. Poor quality, dry cracked hooves are a primary indicator in horses. A tendency toward abscess formation also suggest Silicea. Scarring after injury and ill effects of vaccination also make Silicea a choice. It is a deep acting remedy and should be considered for many chronic cases. In addition to the previous symptoms the constitutional Silicea may be sensitive to heat yet chilly, have swollen glands, and have an excessive dislike for hypodermic injections.
What Vaccinations Should I Give My Horse?
Before I can answer this question I must have information about you and your horse.

1. How old is your horse?
2. How healthy is your horse?
3. What diseases are present in your area?
4. Where and how is your horse stabled?
5. What activities do you and your horse participate in?
6. How fearful are you that your horse will get sick or die if you do not vaccinate?
7. Are you willing to change your management, if necessary, to prevent disease and support your horses immune system.

After these questions are answered I can recommend a vaccination protocol, but it is important for the horse owner to be educated about common equine diseases in order to participate in the final decision. Encephalitis I recommend vaccinating healthy horses for this disease as it can be fatal. Equine encephalitis comes in three forms; Eastern, Western and Venezuelan. All three are combined with tetanus toxoid in one vaccine. This is commonly referred to as a VEW-T or 4-way vaccine. Equine encephalitis is a viral disease transmitted to the horse by mosquitoes which pick up the virus from an intermediate hosts, such as birds, small rodents and reptiles. This means your horse does not get this infection from or give it other horses, so even a backyard horse that never travels is at risk. To my knowledge, no research has been done to determine length of immunity, but vaccine manufacturers suggest annual vaccination. Until further information is available, I would suggest initial vaccination at 5 and 6 months of age followed by a booster every 3 years. If an outbreak is occurring, the booster can be given sooner. I would not vaccinate any horse over 15 years of age unless there is an outbreak.

Tetanus
This disease can also cause death if it is not treated early and aggressively. Tetanus is caused by the bacteria, clostridium teteni, which generally infects the horse through contamination of a wound. Vaccine manufacturers recommend annual vaccination, but horses have been known to have protection for up to 10 years from their last vaccination. I would suggest the same schedule as encephalitis with a booster given if horse sustains an injury and has not been vaccinated within the last 1 year.

Tetanus antitoxin
This is not a vaccine, but an antitoxin against the tetanus neurotoxin. It should be given along with tetanus toxoid to an injured horse with unknown vaccination history. Tetanus prophalaxis should also be considered for such situations as foaling and surgery.

Rabies
Horses can get rabies and it is fatal. To my knowledge there are no documented cases of a horse transmitting rabies to a person. To contract rabies, the horse must be bitten by a rabid animal. Wild animals such as skunks, fox, raccoons or bats are the usual sources of infection. Vaccine manufacturers recommend annual vaccination for horses, although the same vaccine is known to provide protection to dogs and cats for at least three years. There have been cases of rabies in vaccinated horses. I do not routinely advise vaccinating for this disease, but if you are concerned and choose to vaccinate, the manufacturer’s directions should be followed.

Influenza(Flu)
This is a respiratory disease caused by a virus. Symptoms include coughing, fever, loss of appetite and muscle soreness. It is rarely fatal. Uncomplicated cases recover in 1 to 3 weeks. It is acquired from other infected horses. The best treatment is rest and TLC. Immunity from vaccination is of very short duration, often less than 2 months. It is my opinion that vaccination causes more harm than good, and horses will become less susceptible as they mature. A healthy immune system is the best defense. In a study with racehorses, there was no difference in infection rates in vaccinated verses unvaccinated controls when the horses continued to work. In the same study, vaccinated horses that were taken out of hard training during the outbreak had lower infection rates. Unfortunately, this study did not include unvaccinated horses that were rested. I suspect they would have done just as well.

Rhinopneumonitis (Rhino)
This viral disease can take several forms. Equine herpes virus 1 and 4 both cause mild respiratory infection primarily in young horses. Infection is acquired from other infected horses. Like influenza, immunity from vaccination can last less than 2 months. Horses can become latent carriers of the equine herpes 1 virus. This means the horse stays infected but does not show symptoms or infect other horses unless stressed. Once stressed, however, the horse may or may not show symptoms, but can be a source of infection for other horses. Equine herpes 1 can also cause abortion in pregnant mares. When horses are shipped and congregated together there is more stress on latent carriers. These horses may then become viremic and cause abortions in the herd. For this reason, most brood mare farms require mares be vaccinated at 5, 7 and 9 months of pregnancy. Even this procedure does not always prevent abortion, and some mares will not abort even if they become sick. Although I would prefer to take my chances than give these vaccines, you may not have an option if you ship your mare for breeding. If you do not ship your mare, you can use good management to control exposure to the herpes virus. Keep pregnant mares separated from young stock and isolate all horses shipping in for 10 to 14 days before introducing them to the herd.
On rare occasions equine herpes 1 can cause neurological symptoms ranging from mild hind limb in coordination to quadriplegia. I have never seen this from actual infection, but I have often seen pain and persistent hypersensitivity in horses following vaccination. This usually appears about 2 weeks following vaccination, and I do not know if the vaccine causes these symptoms directly or perhaps stresses the horse enough to cause a flare up of a latent infection. Despite all the varied disease states this virus can cause, it is rarely fatal with the exception of abortions. I believe management is most effective as a control measure and vaccination may cause more harm than good.

Steptococcus Equi (Strangles)
This is a contagious bacterial infection of the upper respiratory tract primarily in young horses. It is characterized by nasopharyngeal inflammation, a mucoperulent nasal discharge, and abscessation of regional lymph nodes. It is rarely fatal, although complicated cases do occur. Infection is usually through contact with infected horses. The bacteria can live in the environment and become concentrated where large numbers of horses congregate. It can also be transmitted by contamination of inanimate objects such as water or feed buckets. Infected horses may shed this bacteria for several months following infection. Unfortunately, there is no good vaccine. I do not recommend vaccination with current vaccines on the market.

Equine Monocytic Ehrlichiosis (Potomic Horse Fever)
Equine Monocytic Ehrlichiosis is a blood borne rickettsial disease caused by Ehrlichia Risticii. Clinical symptoms associated with this disease can include severe diarrhea, fever, anemia, leukopenia, edema of the limbs and ventral portions of the body, abortion, colic, and laminitis. Horses can die from this disease, but most recover following appropriate treatment. A study done at Cornell University in 1995 suggested the vaccine for EME did not lower rates of infection or severity of disease. I do not recommend vaccination for this disease.

Conclusion
Planning a vaccination program is an important part of horse care. Antibody titers can be measured by taking blood samples and this may help determine your horse's current immune status to diseases such as Encephalitis, Influenza, Rhinopneumonitis and Rabies. After careful consideration of the 7 questions at the beginning of this article and discussion with your veterinarian, you should be able to determine what is best for you and your horse.

You can do nososdes from Dr Wessner http://holisticvetclinic.net/default.aspx

About the Author
Madalyn Ward, DVM, owns Bear Creek Veterinary Clinic in Austin, Texas. She is certified in Veterinary Homeopathy