Equine_vaccination

Equine Vaccination Overview

Date of Document: 30 May 2024Department: Eq Derm Endo and Clinical Practice

Equine Vaccines

Common Vaccines

1. Equine Influenza

   • A highly contagious viral disease affecting the respiratory tract, which can lead to severe illness, reduced performance, and respiratory complications.

   • Vaccination is crucial due to the high rate of disease transmission, especially in places with close contact among horses (e.g., race tracks, shows).

2. Tetanus

   • Caused by Clostridium tetani, it is a potentially fatal disease leading to severe muscle stiffness and spasms.

   • Vaccination is vital, especially for working horses and those exposed to wounds.

3. Equine Herpesvirus (EHV-1, EHV-4)

   • EHV-1 can cause respiratory disease, abortion in pregnant mares, and neurological disease. EHV-4 primarily causes respiratory illness.

   • Vaccination is essential for pregnant mares and during outbreaks to protect against severe complications.

4. Strangles

   • Caused by Streptococcus equi, it leads to swollen lymph nodes, fever, and in some cases, can result in serious complications like guttural pouch empyema.

   • Vaccination helps control outbreaks, especially in populations of young horses such as foals and yearlings.

5. Other Considerations

   • Rotavirus: Particularly important in young foals; can cause significant gastrointestinal disease.

   • Equine Arteritis Virus (EAV): A viral infection that can lead to respiratory disease and abortion in mares; vaccination is recommended in endemic areas.

Outbreaks Analysis

Historical Outbreak Data

• Major Equine Influenza Outbreak: January 2, 2019 - December 31, 2019

  • Observation:

  • Unvaccinated horses were the most significantly affected demographic.

  • Horses that had longer intervals between vaccinations were notably more susceptible to the virus than those that maintained up-to-date vaccinations.

• Vaccinated Horses Demonstrated:

  • Fewer days shedding the virus, which reduces spread.

  • Fewer clinical signs of illness, which indicates an effective response to vaccination.

  • Recommendation: Horses are advised to be re-vaccinated if it has been more than 6 months since their last Equine Influenza vaccine to maintain effective immunity.

Geographic Spread of Outbreaks

• Affected Areas: Significant outbreaks were noted within the UK, especially in regions like Scotland and key urban centers like Edinburgh and Belfast.

• Detection of Outbreaks: Outbreaks spread primarily through aerosol transmission, highlighting the need for stringent biosecurity and vaccination protocols in high-density equine environments.

Immunity Types and Their Durability

Natural Immunity

• Duration: Short-lived; clinical immunity lasts approximately 1 year, while infection-induced immunity may be even more transient.

• Response: Generates virus-specific immunoglobulins (Ig), including IgA, IgG1, and IgG2, which offer limited protection against reinfection.

Vaccine-induced Immunity

• Duration: Short-lived, typically lasting less than or equal to 6 months post-vaccination for many vaccines.

• Markers: Immunity is monitored through antibody responses to hemagglutinin (HA) and neuraminidase (NA) present in the virus.

• Responses: The response to parenteral (injected) vaccines primarily produces IgG responses, which are critical for effective immunity.

• Adjuvants: Vary in their ability to stimulate antibody production at given HA levels; their effectiveness depends on formulation specifics.

Vaccine Administration Guidelines

General Administration Protocol

• For Equine Influenza Vaccines:

  • The initial series consists of 2 doses administered intramuscularly (I/M), spaced 4-6 weeks apart.

  • A third booster dose is recommended after 6 months.

  • Annual revaccination is suggested for optimal protection, with specifics varying according to guidance from organizations such as the British Horse Association and FEI.

Tetanus Vaccination Schedule

• Tetanus Toxoid Vaccine:

  • Administered as two I/M injections spaced 4-6 weeks apart.

  • A first booster is due 12 months after initial vaccination; subsequent boosters are recommended every 2 years.

  • In cases of injury, an IM injection of Tetanus antitoxin may be required for immediate short-term protection, which is particularly critical for neonates and horses with wounds.

Specific Vaccines Overview

1. Equine Herpesvirus (EHV-1 and EHV-4)

   • Characteristics: While primarily causing mild respiratory disease, EHV can result in far more severe outcomes, including abortion in broodmares or neonatal death.

   • Vaccination Schedule: Comprise 2 doses spaced 4-6 weeks apart, followed by 6-monthly boosters, especially recommended for broodmares to ensure protection during gestation.

2. Strangles Vaccine

   • Vaccination Options:

     • Equilis StrepE: A live vaccine, administered 0.2 ml inside the upper lip every 6 months.

     • StrangVac4: A recombinant protein vaccine given as 2 IM injections 4 weeks apart, then every 6 months; it does not interfere with ELISA tests, allowing reliable disease surveillance.

Resources and Additional Information

Essential Reading:

• Equine Flu Immune Responses: Vettimes Article

• Article Reference: Durham, A. (2019) "Choosing an equine influenza vaccine". In Practice, 41: 84-87. Available through NU Search or in PDF format on Moodle.

Additional Resources:

• Equine Surveillance: Equine Surveillance

Contact Information

• Department Email: svzkp@nottingham.ac.uk

• Browse for additional queries related to equine vaccination, ensuring that the latest protocols and recommendations are followed.