There have been fresh measles warnings issued on Friday night, after a confirmed case was infectious on an international flight and while visiting several locations in Sydney.

NSW Health said the case recently returned from South-East Asia, where there are ongoing outbreaks of measles in several countries, including Thailand, Vietnam, and Indonesia.

The NSW warning follows a Victorian Department of Health alert earlier on Friday, notifying the community of three cases returning from Bali with infections.

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Victoria's Chief Health Officer, Dr Tarun Weeramanthri, issued the health alert after five new cases were detected across the state.

"Two of these cases are locally acquired and linked to the recent local outbreak reported in February," the alert stated.

"Three cases acquired their infection overseas in Bali. These cases have been infectious at multiple locations around Melbourne."

Measles is a highly infectious viral illness that can spread from person-to-person through the air when someone who is infectious coughs or sneezes.

It can potentially lead to serious health complications including pneumonia and brain inflammation (encephalitis).

Both NSW and Victorian health departments are advising people who have been in any of the listed exposure sites either state, on the specified dates and times (below), to monitor for any symptoms.

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"Symptoms to watch out for include fever, runny nose, sore eyes and a cough, usually followed three or four days later by a red, blotchy rash that spreads from the head and face to the rest of the body," South Western Sydney Local Health District A/Director of Public Health, Dr Mitchell Smith said.

"It's important for people to stay vigilant if they've been exposed, and if they develop symptoms, to please call ahead to their GP or emergency department to ensure they do not spend time in the waiting room with other patients."

Symptoms can develop up to 18 days after exposure.

NSW exposure sites

Monday 10 March:

• Vietnam Airlines flight VN773 departed Ho Chi Minh City 9:20pm Sunday 9 March, arriving in Sydney 9:50am Monday 10 March
• Sydney International Airport arrivals terminal and baggage claim from 10am to midday

Thursday 13 March:

• The Children's Hospital at Westmead Emergency Department waiting room from 10:30am to 5:00pm

Victoria exposure sites

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