The state health department has warned people in northern Victoria to take extra measures to prevent mosquito bites, after a person contracted the mosquito-borne Japanese encephalitis virus while spending time in the Buloke Shire and Swan Hill area. The virus is a flavivirus that is common across Asia, but was not found in Australia until recently. Heavy rains, flooding events and summer heat have led to an explosion in mosquito populations on the east coast, and in March 2022, the federal health department declared the outbreak an incident of national significance. Only about 1 per cent of cases in humans are symptomatic, but half of those cases are left with long-term brain damage, and, in a quarter of the cases, patients die. People with severe JEV infections can experience headache, vomiting, disorientation, seizures, coma and more rarely, permanent neurological complications.