Alternative vaccination against equine botulism (BoNT/C).

Area of Science:

• Veterinary immunology
• Equine infectious diseases
• Vaccine development

Background:

• Equine botulism incidence is rising in Europe due to increased haylage feeding.
• Recombinant vaccines offer potential advantages in safety, cost, and tolerability over traditional toxoids.

Purpose of the Study:

• To evaluate the efficacy of a recombinant vaccine candidate (Hc BoNT/C) for horses.
• To compare its immunogenicity and adverse reactions against a commercial toxoid vaccine.
• To assess its potential for inducing neutralising antibodies against botulinum neurotoxin C.

Main Methods:

• Horses were vaccinated with either recombinant Hc BoNT/C or a commercial toxoid vaccine.
• Immune response was evaluated using ELISA, Western blot, and a mouse protection assay.
• Local reactions (oedema, pain) and recovery times were monitored.

Main Results:

• The recombinant vaccine caused minor local swelling (5-day recovery).
• The toxoid vaccine resulted in painful reactions with up to 2-week recovery.
• Both vaccines induced neutralising antibodies after two boosters; recombinant showed earlier seroconversion on ELISA/Western blot.

Conclusions:

• Recombinant Hc BoNT/C is a suitable vaccine candidate for horses, inducing neutralising antibodies against botulinum neurotoxin C.
• The recombinant vaccine demonstrated fewer adverse reactions than the commercial toxoid vaccine.
• No correlation was found between serological response to Hc BoNT/C and serum neutralising capacity.