Allivet’s Horse Vaccine Guide

Core vaccines are those that protect your horse against diseases that are endemic to a region, are virulent/highly contagious, pose a risk of severe disease, those having potential public health significance, and/or are required by law. Core horse vaccines have clearly demonstrable efficacy and safety, with a high enough level of patient benefit and low enough level of risk to justify their use in all horses. These include Tetanus, Eastern/Western/Venezuelan Equine Encephalomyelitis (EEE, WEE, VEE), West Nile Virus (WNV), and Rabies.


Tetanus bacteria are anaerobic and produce a potent neurotoxin (tetanus toxin) that attacks nerves controlling the muscles of the body. Tetanus bacteria multiply rapidly in the damaged tissue. This causes progressively worsening muscular stiffness and spasm. The affected horse will become stiff and have difficulty moving and eating. In advanced cases the horse will collapse with spasms, convulsions, and death from respiratory failure.

The Tetanus Toxoid vaccine is the best way to prevent tetanus in horses. It exposes your horse to a small dose of the bacteria, causing your horse’s body to develop immunity to the disease. However, this vaccine cannot be used to treat an active infection.

Eastern/Western/Venezuelan Equine Encephalomyelitis

The encephalitis viruses are alpha viruses and are spread to horses by mosquitoes from wild birds and rodents. Both viruses are known to occur in North America, with EEE being more prevalent east of the Mississippi and WEE west of the Mississippi. Venezuelan Equine Encephalitis (VEE) occurs in mostly South America and is considered a reportable foreign animal disease in the United States. There is some evidence the EEE/WEE vaccines may provide cross protection against VEE.

EEE and WEE are serious and frequently fatal in horses. Symptoms include fever, depression and neurologic signs which can include altered mentation and vision, wandering, head pressing, circling, ataxia (stumbling) leading to paresis, paralysis, convulsions and often death. Vetera VEWT + WNV protects healthy horses against VEE, EEE, WEE as well as Tetanus and West Nile Virus.

West Nile Virus (WNV)

Like the viruses above, West Nile virus is a mosquito-transmitted disease transferred from infected birds to mosquitos, then horses or other animals. In horses, WNV causes encephalitis, the swelling of the brain and spinal cord. The most common signs of WNV infection in horses include stumbling, uncoordination, weak limbs, partial paralysis, muscle twitching, and in some cases, death.

West Nile Virus can be prevented with West Nile Innovator vaccine. This vaccine protects horses from the WNV and aids in the prevention of viremia caused by West Nile Virus. It is the only WNV vaccine adjuvanted with MetaStim for improved immune response.


Rabies is caused by a virus from the rhabdovirus family. Rabies is a zoonotic disease, which means that there is the possibility of transmission from animals to humans. Rabies is typically passed in the saliva from a bite wound and it affects the nervous system. Affected horses might go off feed or exhibit depression, excessive salivation, difficulty swallowing, lack of coordination, aggressive behavior, hyper excitability, colic, convulsions or paralysis.

Although rabies is rare in horses, it is very important to prevent it. There is no effective treatment once the horse is infected, and the disease is one hundred percent fatal to all infected animals. Rabvac is a killed virus vaccine that can help prevent rabies in horses.

Risk-based vaccines are those selected for use based on risk assessment performed by, or in consultation with, a licensed veterinarian. Risk-based hose vaccines include Botulism, Equine Herpesvirus (EHV), Potomac Horse Fever (PHF), Rotavirus, and Strangles (Streptococcus equi).


Botulism is a high-mortality neurologic disease caused by neurotoxins. These neurotoxins are produced by anaerobic bacteria Clostridium botulinum. The botulinum toxin enters through the bloodstream and affects motor nerve cells. Some of the symptoms include drooling, dropping food, dysphagia (inability to swallow, and inappetence/anorexia.

If left untreated, botulism can be fatal. The BotVax vaccine can help you prevent botulism in healthy horses. It can be used on pregnant mares and helps unborn foals to develop antibodies to protect them when they are first born.

Equine Herpesvirus (EHV)

Equine Herpesvirus is a virus that causes abortion (between 7 an 11 months of gestation), respiratory disease (coughing, depression, fever, inappetence, and nasal discharge), neurological symptoms (incoordination, hindlimb paralysis, recumbency, loss of bladder and tail function, and loss of sensation to the skin around tail and hindlimbs) and neonatal mortality in horses.

Vaccination may reduce the severity and duration of disease. Prodigy with Havlogen protects healthy horses 6 months of age or older from rhinopneumonitis and protects pregnant mares against abortion caused by rhinopneumonitis.

Potomac Horse Fever (PHF)

Potomac Horse Fever is a potentially fatal disease caused by the bacteria Neorickettsia risticii. This bacteria comes from a parasite living in freshwater snails and aquatic insects such as caddisflies, mayflies, damselflies, dragonflies and stoneflies that a horse can likely ingest while grazing. Typical signs include fever, anorexia, colic depression, ileus, diarrhea, and laminitis.

Equine Potomavac protects healthy horses from Potomac Horse Fever. It has shown to be 100% effective in protecting against mortality. The vaccine is a liquid suspension of inactivated bacteria.


Rotavirus is a concern for foal owners. The AAEP estimates that 70% of foals will have at least one bout of diarrhea that will be caused by rotavirus. Horses five months or older are not really susceptible to the virus. Rotavirus damages the villi in the intestines making it difficult for the intestines to absorb nutrients from food. The damage to the intestinal lining makes the foal unable to digest the mare’s milk. This causes diarrhea that can lead to severe dehydration, a situation that can lead to death. The virus is carried in the manure.

Equine Rotavirus is a killed virus vaccine. It is designed for pregnant mares to provide passive transfer of antibodies to foals against equine rotavirus.

Strangles (Streptococcus equi)

Strangles is a contagious upper respiratory tract infection in horses. It is called by the bacteria Streptococcus equi var equi. The disease is manifested in a mild form in older horses, characterized by nasal discharge, small abscesses, and rapid resolution of disease. Younger horses are more likely to develop severe lymph node bascessation that subsequently opens and drains.

You can protect your horse with Pinnacle I.N. Pinnacle I.N. is the first intranasal equine strangles vaccine available to US horse owners.

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