Vaccination is a highly effective way of preventing disease. It works by introducing a harmless form of the virus or bacteria into the body. This causes the horse to mount an immune response to the ‘foreign’ agent which results in the formation of immune cells and proteins such as ‘antibodies’ that are specific for that pathogen. Some of the immune cells are a type of white blood cell known as ‘memory cells’. These are capable of recognising the chemical structure of the foreign agent (which may be a virus, bacteria, fungus or parasite) if they are ever introduced into the body again. The memory cells then induce a rapid immune response that eliminates the pathogenic agent before it has chance to seriously harm the horse.
The two diseases of horses that are most commonly vaccinated against are ‘Tetanus’ and ‘Equine Influenza’, and this article focuses on these 2 diseases.
Tetanus is a bacterial infection caused by ‘Clostridium tetani’.
It is not contagious between horses, but it is present in the environment and can contaminate wounds. Once the bacteria have contaminated the wound they produce a toxin that causes terrible disease that will usually result in death even when the most aggressive veterinary intervention is attempted.
Horses are the most susceptible of all domestic animals to tetanus. Vaccination is the only way
to effectively prevent tetanus. All horses are at risk from tetanus, and the vaccines are very effective.
Equine Influenza is a highly contagious respiratory disease that can be fatal to foals and yearlings, and can cause permanent lung damage to older horses which predisposes to noninfectious airway disease. Vaccination helps to prevent outbreaks that can result in the need to isolate infected horses and/or the cancellation of competitions/events. Equine influenza is a continual threat to the horse population, and outbreaks of the disease still occur in the UK.
Surveillance figures published in January this year show that 2 outbreaks were confirmed in August 2014, a further 8 in September, and another 14 outbreaks occurred between the beginning of October and mid-November. All positive diagnoses were made in unvaccinated horses.