Immunizations are another important aspect of a preventative program for your horse. It is important to vaccinate regularly in an attempt to prevent and/or reduce the risk of certain infectious diseases. Although no vaccine is 100% effective in the face of overwhelming exposure, the severity of the disease can be greatly reduced by vaccinating the horse regularly. These vaccinations stimulate the horse’s immune system and helps them produce antibodies to combat these diseases. If the horse has never been vaccinated, they should receive a booster shot three to four weeks after the initial vaccination.

In this area, we recommend vaccinating against these diseases:

Eastern and Western Encephalomyelitis (Sleeping Sickness) - Vaccinate annually in the spring.  Transmitted by mosquitoes, this viral disease is often fatal.  It attacks the brain and central nervous system.  Symptoms include loss of their appetite, high fever, excitable or compulsive behavior, and may walk blindly into objects. 

Influenza/Rhinopneumonitis (Flu/Rhino) - Most horses in our area are protected by vaccinating two to four times a year.  Vaccinating is very helpful in preventing respiratory disease in horses that are exposed to frequent contact with other horses.  However, the efficacy of this vaccine is short-lived.  Therefore, horses in a high risk environment (those hauled frequently) need to be vaccinated more often and require a special immunization program.  There is a new form of the influenza vaccine.  This intranasal type is administered into the nasal cavity of the horse and creates local protection at the site of infection.  This type provides protection for up to six months and is given twice a year.

Strangles (Streptococcus equi) – Recommended primarily for young horses.  With the Strangles vaccines available today, it is possible to get some protection from this bacterial disease.  There are two forms of vaccines available, injectable and intranasal.  We recommend using the intranasal type.  This vaccine is squirted up the nostril and creates protection directly at the site of infection.  An initial series of two vaccinations given three weeks apart is followed by annual boosters.  Make sure to consult with our staff when using this vaccine.

Potomac Horse Fever - All horses are exposed to this disease regardless of their contact with other horses.  We recommend vaccinating them in the late spring (May or June) in order to get protection throughout the entire Potomac Horse Fever season with a single vaccination.  Fever, anorexia, diarrhea, colic and laminitis are symptoms of PHF.

Tetanus (Lockjaw) – Caused by bacteria entering wounds, foal umbilical cords, or castration.  Symptoms include high fever, muscle stiffness, muscular spasms, and difficulty eating, drinking, and violent reactions to sudden movement or noise.

Rabies - Eastern South Dakota has a high level of rabies in its animal population, especially those located in wooded areas and around creeks.  Rabies is a year round disease, so we recommend an annual vaccination for every horse.

There is no treatment and is almost 100% fatal in cases.  It also poses human risks if contacted with a rabid animal.

West Nile Virus - Mosquitoes are the vector (carriers) for the virus that infects birds (reservoir) when they feed on them.  The virus is able to multiply in infected birds, so that when a different mosquito bites that bird it can transmit the virus to a human, horse or another bird.  Mosquitoes are not able to acquire the virus from any other animal except birds.  WNV cannot be spread between horses, or from horse to humans.  Most birds are able to carry the virus in their bloodstream without becoming ill; only a few birds will become ill and eventually die from this encephalitis.  The clinical signs of WNV in horses are consistent with encephalitis and include ataxia, weakness of one or more limbs, muscle twitching, depression and inability to stand.  And increased temperature has not been a common finding. Based on these clinical signs it is difficult to distinguish WNV from other types of infections that can cause neurological signs.  Other diseases that would have to be ruled out include Eastern, Western or Venezuelan encephalitis, EPM, Rabies, botulism, and Equine herpes virus. Our recommendations for vaccination for WNV are as follows:  For horses that have not been vaccinated, vaccinate with 2 doses- 4 to 6 weeks apart with last dose given by the beginning of May.  For horses that have had both vaccines in the proper time period, booster the vaccine every spring (April or May).  For pregnant mares booster 4-6 weeks before foaling.  For foals from unvaccinated areas give the first vaccine at 3 weeks to 1 month of age followed by 2 boosters each 4 to 6 weeks apart.  For foals from vaccinated mares (vaccinated 4 to 6 weeks before foaling) give the first vaccine at 3 months and booster at 4 and 5 months.