The woman visited multiple locations around Ballarat from April 28 to May 4.

With an incubation period of 10 to 14 days, anyone infected with the illness could begin to show symptoms until May 22.

The list of times and locations the woman visited while potentially infectious include:

The woman was one of four Victorians diagnosed with the disease this week.

Victoria's acting chief health officer Dr Angie Bone said the patients were being treated and recovering in hospital, having acquired the illness while they were overseas.

"Anyone who is unvaccinated is at highest risk of contracting measles," Dr Bone said.

"People need to have received two doses of measles-containing vaccine to be fully protected. Many adults have only received one vaccine against measles and therefore most cases are in this age group."

Measles symptoms include fever, a severe cough, conjunctivitis, runny nose, a rash that typically starts on the face, and generally feeling unwell.

Patients can be infectious roughly five days before, to four days after, the appearance of the rash. Measles is highly infectious and can persist in the environment for up to two hours.

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"Most people born before 1966 will have been exposed to measles in childhood, and therefore will be protected," Dr Bone said.

"This means if you are an adult born in or after 1966 - especially if you are planning travel overseas - you may be susceptible and should contact your GP to get vaccinated - and a free Measles, Mumps, Rubella vaccine is available."

Measles is widely circulating throughout much of south east and southern Asia, meaning travellers must be aware of the risk and symptoms.

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