It’s Springtime! The grass is growing, flowers are blooming, and birds are singing. And, it’s time to update your horse’s vaccinations! Vaccinating your horse to protect him from disease is a very easy thing to do. Most vaccines are given quickly and easily by intramuscular injection in the neck or hip.

Vaccines are critical to preventing spread of dangerous diseases. Through their use, many previously fatal diseases are almost nonexistent. Vaccinations work by the injection of a killed or altered form of the disease causing organism into the body. This causes the body to work to determine the best antibodies to use in an attack against the pathogen. Because the organism is killed or altered, it is nonfunctional and does not cause disease, but the immune system remembers the best strategy for destroying the pathogen. The next time the horse comes in contact with the disease causing organism, his immune system immediately knows how to fight it and he does not become ill. Occasionally, a vaccination can produce local swelling, soreness or rarely, an allergic response.

Prevention

Following is a list of vaccinations available for horses. Initial vaccinations are usually given after the horse has reached three months of age.

Rabies

This vaccine was recently approved for horses. It contains a killed virus to protect against this disease, which affects the central nervous system and results in death. This disease has been on the rise lately and is transmissible from horse to human, thereby posing a severe public health problem. This is an annual vaccine only.

Tetanus

An acute, infectious disease that is caused by the bacterium clostridium tetani, which enters wounds from the horse’s environment. The vaccination is a modified toxin that is administered annually. The first vaccination is followed by a second dose in four to six weeks. If you do not have your horse re-vaccinate on a yearly basis, you must administer two doses as if you are initially vaccinating the horse.

Eastern and Western Encephalomyelitis

This is an acute viral disease seen in birds, rodents, horses, and man that is transmitted by the mosquito. The vaccine is a killed virus that is initially followed by a second dose in three weeks. Annual re-vaccination is required thereafter. Vaccination is best given in the Spring before the mosquito season.

Rhinopneumonitis

This is a viral disease caused by the equine herpes virus. It was originally thought to be just one virus, but two strains have now been found. The vaccine EHV-1 protects the horse against abortion and a nervous system disease that can cause paralysis. EHV-4 protects horses against the respiratory form, which accounts for nearly half of all equine respiratory disease.

Influenza

A highly transmittable viral disease that affects the upper respiratory tract of the horse.  The vaccine is a killed virus consisting of a combination of the two most common strains of influenza. Administered in two doses, the second one is given three weeks after the first. The manufacturer recommends administering every three to four months in horses that come into contact with many other horses, such as when showing, parades, etc.

Strangles

An extremely contagious bacterial disease that causes respiratory tract abscesses, especially in the throat and neck areas. Vaccine is a killed bacterium given in two doses, three weeks apart. Annual re-vaccination is given thereafter. The vaccine may not be administered during an outbreak or when a confirmed case has been documented within a facility in the last year.

Potomac horse fever

It is caused by a type of tiny bacteria, Neorickettsia risticii, which is carried by a fluke that inhabits insect larvae. The horse becomes ill when he ingests these larvae, usually through water sources. Symptoms include fever, depression, poor appetite, diarrhea, and sometimes founder. Also pregnant mares can abort. Vaccination is best given early in the Spring in two doses administered three week apart with annual re-vaccination thereafter.

West Nile Virus
A viral disease that is spread by the mosquito.  The virus infects the central nervous system and causes symptoms of encephalitis including loss of appetite and depression, and possibly fever, weakness or paralysis of hind limbs, muscle spasms, impaired vision, lack of coordination, convulsions, inability to swallow, circling, hyperactivity, or coma. Vaccination is with one of four available vaccines; three killed and one live altered virus. Typically administered early in the Spring in three initial doses, each three weeks apart, and then following with one annual booster.

Botulism
Botulism caused by entry into the horse’s system of a tiny microorganism called Clostridium botulinum. It is closely related to the bacterium that causes tetanus but is more lethal. Symptoms of infection include depression, fatigue, muscle spasms, tongue hanging out, and eventual breathing difficulty and death. The recent increase in frequency of botulism in horses is due to the increased technology of the hay mowing and baling process. Larger, faster machines often catch small animals in their mowing or baling, which deteriorate in the bales or silage, promoting botulism growth. There is one vaccine available that is a killed virus. Vaccination is in three initial doses, three to four weeks apart, and an annual booster thereafter.

Your vaccination program should be simple and consistent. Some people question the necessity of vaccines because of the infrequency of actual cases of many of the diseases, but a consistent vaccination program is precisely why we do not see these diseases more often.

Talk with your veterinarian and set up a vaccination program. He can guide you as to the necessity of each vaccination depending upon your horse’s living environment, association with other horses and current disease threat.

So, be sure to do that spring thing and vaccinate!