from the jugular vein of the horses, dams and foals on Days 0 (prior to vaccination), 7, 14, and 21 days after the first vaccination. Foals were given a booster vaccination and additional blood samples were obtained days 7, 14, and 21 post booster vaccination. Foals and dams were housed together in the same pasture. Horses were pastured separately. Serum IgM and IgG titers were measured at a com- mercial laboratory using Capture ELISA (MAC) tests and plaque reduction neutralization test (PRNT), respectively. All MAC-ELISA titers for WNV and EEE were negative at 1:400 for the study population. In the adult horses, PRNT ti- ters ranged from 1:10 to 1:100 for EEE and 1:100 for WNV at all times. In the pony foals, PRNT titers to EEE and WNV ranged from nega- tive to 1:10 prior to vaccine administration to 1:100 after the second vaccination. One foal had negative PRNT titers to EEE throughout the experiment. Vaccination with a commercially avail-
able multivalent vaccine containing WNV and EEE did not result in IgM antibody titers 1:400 in horses and ponies. Therefore, vaccination for EEE and WNV using this product does not interfere with current diagnostic testing for EEE or WNV using the MAC-ELISA.
Acknowledgments
Declaration of Ethics The Authors have adhered to the Principles of the Veterinary Medical Ethics of the AVMA.
Conflict of Interest
This study was funded by Boehringer Ingelheim Vetmedica. Drs. Keene and Grubbs are employees of Boehringer Ingelheim Vetmedica.
Footnote a
Vetera Gold, Boehringer Ingelheim, St. Joseph, MO 64506.
