There has been concerning news that the Japanese Encephalitis (JE) virus has been detected in eastern Australia. The virus has been detected in piggeries in Queensland, New South Wales and Victoria. JE traditionally occurs in a widely dispersed areas in eastern Asia and until now, as far south as Papua New Guinea and islands of the Torres Strait. This mosquito-borne virus can cause disease in humans, horses and pigs. The virus can cause variable signs in horses, ranging from asymptomatic infection (most common) through to fatal encephalitis. Three clinical syndromes are recognized in horses: a) transient fever for 2-3 days with loss of appetite and sleepiness, followed by uneventful recovery; b) lethargy with fluctuating high fever (up to 41 degrees C) and ataxia with recovery in around 7 days; and c) excitability with high fever, dementia, blindness, muscle fasciculations, ataxia, leading to recumbency, coma, seizures and death.