Hong Kong is seeing a record number of cases of scarlet fever – over 400 so far – this year.
That is two to three times more than the norm.
Initial tests by the University of Hong Kong show the bacteria causing scarlet fever may have mutated, making the disease more contagious.
Health authorities also warn of an unusually high prevalence of the disease in the region.
Hong Kong health officials are urging the public, especially parents with small children, to remain vigilant amid a spike of scarlet fever cases in the city.
There have been 419 cases so far this year – a record high for Hong Kong.
So far, the disease has already claimed the life of a seven-year-old girl last month.
Children between the ages of three and 10 are most vulnerable to the disease.
Health authorities said “Group A Streptococcus” is the bacteria which causes the disease.
The Center for Health Protection said that the rise in scarlet fever cases is not just hitting Hong Kong.
Thomas Tsang, controller of the Hong Kong Centre for Health Protection, said: “We notice that this is a regional phenomenon not limited to Hong Kong. We found an increased scarlet fever incident is also found in mainland China as well as Macau, so that points to something of a more diverse, geographical circulation.”
Typical symptoms are a rash, fever and a strawberry-colored tongue.
Doctors said the disease can be treated with antibiotics such as penicillin.
However they said parents should take their children to the doctor right away if they show any symptoms, as it is crucial to nab the disease early on.
As the disease is passed through respiratory secretions, doctors are urging people to maintain good public hygiene, such as regularly washing their hands.