Evaluation of a BE-inactivated whole virus preparation using an encephalomyocarditis virus strain that was isolated from fatal infection in orangutans

A novel Encephalomyocarditis virus (EMCV) of the group 3 cluster (EMCV-3) was first reported in 2002 to be responsible for the deaths of orang-utans in an outbreak in the Singapore Zoo. After this first outbreak, sporadic infections among the primate population caused by EMCV-3 continued to be reported, suggesting that the virus remains prevalent in Singapore. To prevent future infections, we constructed an experimental vaccine using binary ethylenimine (BE) to inactivate the EMCV-3 virus. The immunological performance of the BE-inactivated (BEI) virus was analysed in mice and the neutralising titre of the immune sera measured against the wild-type EMCV-3. The BEI virus showed a strong immunological response in BALB/c mice at 1: 40,960 titre, suggesting that it can be used as a promising experimental vaccine candidate to prevent EMCV-3 infections.