Equine Vaccinations – Is Your Horse Fully Protected

Equine Vaccinations – Is Your Horse Fully Protected

Written by – Hannah Briggs BVetMed MRCVS, Lambourn Equine Vets

What vaccinations do I need for my horse?

There are a variety of equine vaccinations recommended for horses and ponies, these include Equine Influenza, Tetanus and Strangles. Additionally, Rota Virus is recommended for pregnant mares.

We are fortunate here in the UK that we have effective vaccines to the ever evolving viruses that threaten the well-being of our horses. Other countries such as the USA and Europe have many more diseases, not all of which can be vaccinated for.

Equine Influenza

Currently only 40% of the population receive equine vaccinations for Equine Influenza Virus (flu). Equine Influenza virus is a contagious disease that spreads by aerosol droplets between horses and nasal secretions on brushes, clothing and equipment. The rate of transmission is nearly 100% between an infected horse and those with little or no immunity to the virus. For this reason quick identification and isolation of those horses in contact with the infected horse is essential to stop the rapid spread through the horse population.

Influenza symptoms develop within 1-3 days of exposure and include pyrexia (fever), inappetance, clear nasal discharge, dry harsh cough and weakness. Clinical signs will last for around 3 days in straightforward cases. Some horses will go onto develop secondary bacterial infections, such as chronic bronchitis, pneumonia or pleuropneumonia, as a result of the damage caused by the virus to the respiratory tract. These will require further veterinary treatment. In these cases, recovery may take several weeks to months and can be very expensive.

It is rare for fatalities to occur, however severely immune compromised patients should be considered particularly high risk. Vaccination consists of a primary course of three vaccines, one then one a month later and a third six months after the second. FEI competition horses are required to have had a flu vaccination within 6 months and 21 days of a competition due to the increased risk of transmission associated with transport and mixing horse groups. Lower risk horses would require only annual boosters after the primary course.

Tetanus

Tetanus is caused by spores from a bacteria (Clostridium tetani) that is found in the soil and gains entry to cause disease through wounds. Horses are particularly susceptible to tetanus and can be infected via the smallest of damage to the skin, mouth or foot.

The clinical signs of tetanus are often not seen until 10-14 days after the wound occurred. The bacteria releases neurotoxins that cause the blockage of neurological signals and the uncontrolled contraction of muscles. Muscular contraction starts local to the wound and then spreads around the body. The resulting disease is extremely debilitating and often results in euthanasia or death of the infected horse due to the intensive nursing required but also due to the respiratory and heart muscles being affected.

Horses are at a high risk of tetanus as they are exposed to it from their environment. However, tetanus is a preventable disease when a suitable equine vaccination programme is used. This consists of two primary vaccines a month apart followed by a booster the following year and then biannually. Most horses receive a combined flu and tetanus booster vaccination.

Strangles

Strangles is a bacterial disease caused by Stretococcus Equi Equi that spreads rapidly between horses by nose to nose contact or contamination of equipment with nasal secretions. There is a commercially available vaccine, although its use is not widespread.

Equine Vaccinations are just as important at any stage or life.

Herpes Virus

Herpes virus causes respiratory disease and abortion  It is transmitted via direct contact but also through nasal secretions, aborted foetuses and associated fluids contaminating bedding, equipment and clothing. Incubation takes 2-10days to show after infection with the virus.

Another strain of herpes is responsible for the neurological form which has had notable outbreaks in recent years, unfortunately this strain of Herpes can’t be vaccinated for. Herpes virus is significant in the pregnant mare as infection can cause the mare to abort as late as 12 weeks after contracting the virus. For this reason it is advisable that equine vaccinations for are up to date in pregnant mares for herpes, this is usually done at 5months, 7 months and 9 months of gestation. Competition horses herpes vaccination programs varies depending on the age and type of the horses involved with boosters every 3-6 months.

Rota Virus

Pregnant mares should also be vaccinated for rota virus. Antibodies created in response to the vaccine will be passed to the foal via colostrum when it is born. Rota virus is generally only seen as a disease in young foals (<2months old) and rarely seen in older horses. It causes damage to the intestinal tract and results in profuse diarrhoea. It is extremely contagious to other young foals and can be life threatening due to foals becoming rapidly dehydrated and malnourished. These foals require lots of nursing care and should be isolated from other foals. To provide adequate protection mares are vaccinated at 8, 9 and 10 months gestation.

Sadly there are still a significant number of horses not to be vaccinated, with common reasons being that the horse doesn’t compete, he doesn’t leave the yard or that he is old. All these groups of horses are still at risk of contracting flu, particularly our geriatric patients as their immune systems become less efficient with age.

Equine vaccinations, in particular influenza and tetanus, should be considered a routine and essential part of health care for our equine companions to prevent them from being left vulnerable to diseases.