Trials For Preparation Of Combined Vaccine Of Equine Influenza, Equine Herpesvirus–1, Rabies Virus And Tetanus Toxoid

Abstract

A combined vaccine of Equine influenza (EI), equine herpesvirus–1 (EHV-1), rabies virus and tetanus toxoid adjuvanted with saponin and Alhydrogel was prepared. Quality control testing of such vaccine revealed that it was free from foreign contaminants, safe for Guinea-pigs, mice and mares. It was inoculated into Guinea -pigs as a preliminary evaluation for its potency and it was proven safe and potent. Also, it exceeded the permissible protective level allowed to be used for the vaccination of horses. Two groups of mares were used for evaluating the potency of the vaccine. The first one received two doses (5 ml) of the prepared vaccine with 4 weeks interval while the 2nd group was kept without vaccination as control. The mean haemagglutination inhibition (HI) influenza antibody titer reached its maximum at the 2nd month post-vaccination (MPV); 2048 while EHV-1 antibodies reached the peak at the 3rd MPV as recorded by ELISA and neutralizing indices; 1790 and 3.50. Rabies antibodies were detectable in vaccinated mares by the 2nd week post-vaccination showing titers of 16 and 1.0 by serum neutralization test (SNT) and ELISA, respectively recording their peaks (128 by SNT and 2.15 by ELISA) at the 2nd MPV. Tetanus antitoxic titer increased till reaching the peak at the 2nd MPV (40IU/ml) as determined by toxin neutralization test. Depending on these results, it could be concluded that the prepared inactivated EI, EHV-1, rabies and tetanus vaccine is safe and potent for mares providing them with good protective levels of specific antibodies against the 4 used antigens up to 6 months.

Keywords

• vaccine
• equine influenza
• herpesvirus-1
• rabies
• tetanus