NT Health has declared an outbreak of Murray Valley encephalitis following seven confirmed cases, including two deaths and one person currently in a critical condition at hospital, which marks the highest number of cases recorded in a single year.

Two cases involved infants originating in the Big Rivers region, three in the Barkly region, and two in the Top End region.

This record seven cases this year compares to two cases over the previous five years across the Top End.

The most recent MVE case is currently in a critical condition Royal Darwin Hospital and likely acquired the infection while travelling to “recreational areas in the Top End region between April and May”.

There have been six fatalities from MVE over the past 20 years. The infection can be fatal in up to 30 per cent of cases.

Symptoms of MVE consist of severe headache, high fever, drowsiness, tremor, and seizures (particularly in children). In some cases, MVE can lead to delirium, coma, permanent brain damage or death.

People most at risk of mosquito-borne diseases include infants and young children, newcomers to the Territory and people close to mosquito breeding areas after sundown.

The only way to prevent MVE is by avoiding mosquito bites.

To lessen the risk of mosquito bites, people are urged to use a protective repellent containing DEET, Picaridin or oil of lemon eucalyptus; wear light-coloured protective clothing (long sleeves, trousers, and socks) when outdoors in mosquito-prone areas; avoid outdoor exposure around dusk and dawn, and at night near areas of dense vegetation or areas of high mosquito activity; and use mosquito-proof accommodation and camping facilities at night.

“The high-risk period for serious mosquito-borne diseases in the NT is from February to the end of June. The high number of MVE cases we are seeing is likely related to the heavy rains the NT had earlier this year,” NT Heath Director of the Medical Entomology Unit Nina Kurucz said.

NT Health said that Japanese encephalitis (JE) is another dangerous mosquito-borne disease that has been discovered in the Territory where three cases, including one death, have been verified since February 2021.

Further precautions such as the use of mosquito coils, mosquito lanterns and barrier sprays containing bifenthrin in patios and outdoor areas near houses are advised.