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Biosecurity Alert - Mosquito borne disease detected in Victoria

Racing Victoria would like to make you aware of a biosecurity alert from Agriculture Victoria. The alert outlines the detection of Japanese encephalitis in Victoria. The Japanese encephalitis virus can affect horses so you should take precautions to protect your horse(s) from mosquitoes.

In horses, symptoms include lethargy, nervous signs or sometimes hyperexcitability.

Steps you can take to protect your horse(s) from mosquitoes include the use of mosquito repellents and removing mosquito habitats often found in tall grasses, weeds and close to water sources.

Key information and updates:

Frequently Asked Questions:

  • What is Japanese encephalitis (JE)? Japanese encephalitis (JE) is a mosquito-borne viral disease that can cause reproductive losses and encephalitis in susceptible animal species. It is caused by Japanese encephalitis virus which is a member of the Flavivirus genus.

  • How is JE spread? The virus is primarily spread by mosquitoes feeding on infected animals and does not usually spread directly from animal to animal (i.e. it is not considered contagious). Certain types of mosquitoes can become infected with JE such as Culex sp. and these tend to most active at dawn and dusk. Animals with the infection do not transmit the infection to other animals but may infect mosquitoes if bitten while they still have the virus in their blood. In general, spread is through the movement of migratory birds and through the movement of infected mosquitoes, often over long distances due to wind dispersal.

  • Which animal species are affected by JE? JE disease occurs most commonly in pigs. Horses can also be infected and rarely other animals. Pigs and water-birds such as herons and egrets are an important part of the transmission cycle as they can amplify the virus and provide an ongoing source of JE to infect local mosquito populations.

  • Horses: In horses many cases are asymptomatic and most clinical disease is mild, however more severe encephalitis can occur which may be fatal. Signs include fever, jaundice, lethargy, anorexia and neurological signs which vary with severity of the clinical disease. Neurological signs can include incoordination, difficulty swallowing, impaired vision, and rarely a hyperexcitable form occurs. Disease has also been reported in donkeys.

It is important that you report any Japanese encephalitis virus related concerns to the Emergency Animal Disease Watch Hotline on 1800 675 888.