Britain could be on the brink of a major measles outbreak after two major cities were struck by the virus.
Liverpool and Leeds have been hit an outbreak and there are warnings Manchester could be next in line.
If so, there are fears the outbreak could then spread further afield.
Widespread use of the measles vaccine has prevented mass outbreaks recently, there are fears it could still spread as an outbreak can take hold very quickly.
Anyone can get measles if they have not been vaccinated, or if they have never contracted the disease before.
The disease is most common among children.
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Symptoms include a runny nose, sneezing, tiredness and high temperatures.
Patients also develop a rash up to four days after initial symptoms and many also find small greyish-white spots in their mouth before the rash strikes.
Those who feel they might be most at risk have been urged to stay at home and contact their GP or phone NHS 111 for advice.
Anybody who has been in close contact with anybody who has been suffering from measles recently, has also been told to get in touch with their doctor.
Measles is a highly infectious viral illness that can be very unpleasant and sometimes lead to serious complications.
The infection usually clears in around 7 to 10 days.