The report in the Second Quarter of 1997 of Japanese encephalitis occurring in Korea among recently imported horses re-emphasises the serious consequences that can occur following the international movement of horses if appropriate preventive measures are not taken.
Japanese encephalitis is a mosquito borne viral disease affecting mainly pigs, horses and humans.
It causes abortion in pigs and fever and encephalitis with deaths in horses and humans. The disease is widely distributed in Asia including countries such as Japan, Korea, Thailand, Malaysia and India which in recent times have increased the number of horses they import from North America, Australasia and Europe. An inactivated vaccine against the disease used in Japan since 1948 has significantly reduced mortality among horses over the years and horses in Hong Kong and Singapore are routinely vaccinated against Japanese encephalitis. The only source of equine vaccine is currently from Japan although a live vaccine is utilised in China. However it would seem prudent to advise those who import horses to Asian and Pacific Rim countries from outside that region to ensure all horses are vaccinated against Japanese encephalitis on arrival and to avoid importation during the rainy season.