Doctors have warned of a possible measles outbreak in Melbourne after four cases of the highly contagious virus were confirmed this week alone.
So far one man, two women in their twenties and one woman in her 40s have been affected.
The outbreak is contained to the Brunswick and East Brunswick areas of Melbourne, Victoria, but experts warn that it is likely to spread further afield.
The Age reports that Dr Roscoe Taylor, Victoria's acting chief health officer, is bracing for further cases.
"There is a very high probability of further infection. This is just the first wave," he said.
"Measles has an incubation period of up to 18 days so illness acquired from contact could still be coming through and cases could still remain infectious for many days."
Dr Taylor urged anyone affected by the virus to seek medical help.
"Anyone developing these symptoms is advised to ring ahead to their doctor or hospital and alert them that they have fever and a rash," he said.
"If you know you have been in contact with a measles case please alert your GP or hospital emergency department. The doctor or hospital will then be able to provide treatment in a way that minimises transmission."
The health department has warned doctors to be on alert for further cases of the virus, with symptoms including a fever, sore throat, cough and a rash.
The Light for Riley Facebook page has also shared news of the outbreak, posting:
There have been at least 4 cases of Measles in the Brunswick, VIC area this week - this is the same area that had a chickenpox outbreak late last year.
Please watch out for any symptoms if you've been in the area. Babies are not vaccinated against this disease until they reach 12 months.
Women in their 20s to 40s can be vaccinated against measles for free under the Victorian government's initiative to ensure women of child-bearing age are protected against rubella, and it is also free for everyone under 20 as part of the federal government's catch-up campaign.
The page is run by the parents of Riley Hughes, who died of whooping cough at four weeks of age as he was too young to be vaccinated. His parents have since become vaccination advocates.
The National Immunisation Program for children between one and four years includes the Measles, Mumps and Rubella (MMR) vaccine.
It is also available for people under 20 as part of the federal government's catch-up campaign, while women of childbearing age can also receive the vaccine for free under a Victorian government's initiative to ensure women of child-bearing age are protected against rubella.