Japanese Encephalitis Vaccine Might Offer Some WNV Protection

Vaccination against Japanese encephalitis might mitigate West Nile virus (WNV) infection in some horses, said a group of researchers from Japan's National Institute of Animal Health in a recent paper.

Outbreaks of WNV have been reported in many countries, including the United States, but it has not yet been detected in most Asian countries. However, the horse industry is concerned that the virus can migrate to Asia.

Japanese encephalitis (JE) is a related virus that is endemic in Japan. Most horses there are vaccinated against it. The study authors noted that previous research has shown that some other animals vaccinated with JE vaccine also have some protection against WNV.

The researchers infected two groups of horses with WNV. One group was vaccinated with inactivated Japanese encephalitis vaccine, while the other was not vaccinated.

Based on their results, the authors suggested illness caused by WNV might be milder in horses vaccinated with inactivated JE-vaccine than in unvaccinated horses.

The study, "Antibody responses induced by experimental West Nile Virus infection with or without previous immunization with inactivated Japanese encephalitis vaccine in horses," was published in the July issue of the Journal of Veterinary Medical Science. The abstract is available on PubMed.  

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