A Sydney woman has been diagnosed with the measles in what is the third locally-acquired case of the infection in NSW.
The woman, in her 30s, had not travelled overseas prior to her illness and had no known connection to other measles sufferers, NSW Health said in a statement on Thursday.
She is believed to have been infectious from 11 to 24 September and visited locations in the inner west and Sydney's CBD, including two medical centres.
She also travelled by train from Marrickville into the CBD and back again while infectious, NSW Health said.
Health authorities are now seeking to identify people who were in contact with the woman, including those at the medical centres and her workplace.
"It is likely that other people have been exposed to this case or other unidentified measles cases in the community so everyone needs to be on the lookout for the early signs of measles," acting communicable diseases health director Christine Selvey said in a statement.
The woman is the third recent case of locally-acquired measles in Sydney not linked to a known measles case, Dr Selvey added.
Symptoms include fever, sore eyes and a cough followed by a red, blotchy rash that spreads from the head to the rest of the body.
The measles vaccine is free for anyone born during or after 1966 who doesn't have two documented doses of measles vaccine.
