At the outbreak of Bovine Ephemeral Fever (BEF) in the dairy cattle in Taiwan in 1984, the isolation of the causative virus was successfully attempted. As the situations of epizootic required for an effective way to control further prevalence, both Jive and inactivated vaccines were developed and used in the emergency control program.
Using limiting dilution techniques, tht isolated virus was cloned at 12th passage in BHK 21 cells and used as seed virus for live vaccine development after 2 more passages. The saftiness and the efficacy of the vaccine have been tested with 39 dairy cattle in the dairy farms. After the inoculation of the live vaccine, antibody titer was first de-tectable in 2nd week and it reached 12 at 4th week. Immune respon was good (100%). Either vaccination, first with live vaccine followed by 2nd Jive vaccine (LL) or followed by inactivated vaccine (LK) has induced satisfactory neutralizing anti-body, 64 and 145 respectively. Five months after the vaccinations, the titer still remained 32 for LL and 64 for LK method.
Five cows each in LL and LK groups were challenged with virulent virus 14 days after the second vaccination and elapsed without any clinical signs. A total of 50,195 doses of this live vaccine has been used for the initial emergency control of BEF in 1984.
Using formalin inactivation and alumi• nium phosphate absorption method, an in-activated vaccine was also developed. The vaccine was safe and produced in a geome-tric mean antibody titer of 1.6 in the !st week, 3.2 in the 2nd and reached 8 in the 4th week.
The 2nd vaccination at the 4th week (KK) has strongly boostered the production of titer which maintained at 128 for 5 months. This titer was somewhat higher than that of LL or LK method. From Autumn 1984 to early 1985, 50,514 doses of this inactivated vaccine were delivered to farms for the follow up vaccination program.