Enrollment of healthy horses following routine vaccination
Horses were selected based on health status and historical information
that they had been on an AAEP-approved vaccine protocol for annual
vaccinations. Enrollment criteria included that the owners reported
routine annual vaccines had been administered and confirmed no previous
adverse vaccine reactions observed. Information was collected via a
client questionnaire for all enrolled animals (supplemental
information). Horses were determined to be healthy and able to receive
routine annual vaccinations following physical examination by a
veterinarian (CAB). All horses received the same type of vaccine that
were administered by the same veterinarian (CAB). Vaccines administered
included a combination against Eastern equine encephalitis (EEE),
Western equine encephalitis (WEE), tetanus, West Nile virus (WNV),
equine influenza, and equine herpesvirus-1 and -4
(EHV-1/-4)8 and a separate vaccine against
rabies.9 All vaccines were administered
intramuscularly following label instructions and site of administration
was recorded in individual medical records.
Sixty-five healthy horses were enrolled in the study. Horses were either
client-owned with client consent or part of the Kansas State University
College of Veterinary Medicine (KSU-CVM) teaching herd horses. A
convenience sample of client-owned horses and all KSU-CVM teaching herd
horses that were due for their annual booster vaccinations during the
months of March through July were enrolled into the study. Healthy
horses were comprised of Quarter horses (n=39), Thoroughbreds (n=9),
Warmbloods (n=5), Appaloosas (n=3), Paints (n=3), Morgan (n=1),
Miniature (n=1), Mustang (n=1), Draft (n=1), Haflinger (n=1), and a
Tennessee Walking Horse (n=1). All horses were between 3 and 32 years of
age. Thirty-three were mares, 31 were geldings and 1 was a stallion.
All 65 healthy horses had blood samples obtained on days 0, 14, 30, 90
and 180 after vaccination. Nineteen of the 65 horses also had blood
samples obtained on day 270 after vaccination. Twenty-one of the 65
horses also had blood samples obtained on day 365 after vaccination.
Eight of the 65 horses had blood samples collected at both 270 and 365
days after vaccination in addition to the 0, 14, 30, 90, and 180 day
time points.
In an effort to determine if there was an age-associated response to
BSA-specific IgE expression following vaccination, horses were grouped
by age. Subject grouping included horses as young adult (3-9 years),
adult (10-14 years), middle aged (15-19 years) and geriatric (20-32
years) as detailed in Table 1.