GANNAWARRA residents have been warned to protect themselves from mosquitoes following a rise in suspected Japanese encephalitis virus (JEV) cases, which has also killed piglets in the neighbouring Loddon Shire.
Japanese encephalitis is a serious infection of the brain caused by a virus that can be spread by some types of mosquitoes.
Most JEV infections are asymptomatic, however those with severe infection – fewer than one per cent – may experience headache, vomiting, disorientation, seizures, coma, and more rarely, permanent neurological complications or death.
The virus has also now been confirmed as the cause of death of piglets at three separate pig farms in Victoria’s north; one in the Loddon Shire, one in the Campaspe Shire and one in the Wangaratta Shire.
Agriculture Victoria has established an incident management team with staff on the ground to conduct surveillance activities and to provide information and advice to farmers.
Chief Veterinary Officer Dr Graeme Cooke said that since the announcement of the first positive Japanese encephalitis detection last weekend, a number of Victorian farmers had made contact with Agriculture Victoria and submitted samples for testing.
“Japanese encephalitis virus causes reproductive failure in pigs, primarily through stillbirths and piglets that may show signs of central nervous system disease,” Dr Cooke said.
“Infection is not spread directly from pigs to people and there is no risk to humans from eating pig meat.
Agriculture Victoria is also encouraging horse owners to take steps to protect their horses as they are also susceptible to Japanese encephalitis if bitten by infected mosquitoes.
In horses, symptoms include lethargy, nervous signs or sometimes hyperexcitability. To date there have been no confirmed cases of Japanese encephalitis in horses in Australia.
“Horse owners are encouraged to reduce mosquito breeding grounds near their horses to reduce the chances of them being bitten,” Dr Cooke said.
“Stabling at night, the use of a light cotton rug and fly mask and application of a safe insect repellent may also help.”
Victoria’s Department of Health and Human Services says people living, working or visiting towns in the Murray River area between Mildura and Wodonga who have experienced symptoms should seek urgent medical attention.
Several cases of encephalitis of uncertain cause were initially identified in New South Wales, near the Victorian border, and in South Australia within the past month.
There are now several additional cases in Victoria and all cases had extensive mosquito exposure before illness onset and were in the areas near the Murray River.
In the past week, there have been eight suspected human cases of JEV infection in Victoria, including six people in hospital.
The department said the risk may be increased particularly near the Murray River and its surrounds, where increased mosquito numbers have recently been detected and people with increased exposure to mosquitoes may be at a higher risk of infection, particularly people camping, or working or spending time outdoors along the Murray River.
Deputy Chief Health Officer Associate Professor Deborah Friedman said the eight people hospitalised all had exposure to mosquitoes before they became unwell.
“It’s really important for people to protect themselves from mosquito bites, especially anyone who lives, works or plans to visit areas in northern Victoria where mosquitoes are prevalent, especially if they are camping,” Prof Friedman said.
“There are some really simple steps people can take, including covering up exposed skin, wearing loose-fitting clothing, using repellent and sleeping under mosquito nets if you’re outdoors,” she said.
Children aged under five and older people who are infected with JEV are at a higher risk of developing more severe illness.
Encephalitis is the most serious clinical consequence of JEV infection and illness usually begins with sudden onset of fever, headache and vomiting.
Mental status changes, focal neurological deficits, generalised weakness, movement disorders, loss of co-ordination and coma may develop over the next few days.
The encephalitis cannot be distinguished clinically from other central nervous system infections and the incubation period is usually between six and 16 days.
Japanese encephalitis is an urgent notifiable condition that must be notified immediately to DHHS if suspected or confirmed by medical practitioners and pathology services.
A vaccination program targeting those most at risk is expected to begin shortly.*breakout*
WHAT TO DO ABOUT MOSQUITOES
● Wear long, loose-fitting clothes outdoors.
● Use effective mosquito repellents containing picaridin or DEET on all exposed skin.
● Try to limit outdoor activity if lots of mosquitoes are about.
● Use “knockdown” fly sprays and plug-in repellent devices indoors.
● Sleep under mosquito nets treated with insecticides if there are no flywire screens on windows on the home or are sleeping in an untreated tent or out in the open.
● Use mosquito coils, which can be effective in small outdoor areas where people gather, sit or eat.
