MS-2000

You are a GP and your next patient is a 5-year-old girl who has developed a maculopapular rash. The rash started behind her ears and has now spread all over her body. Her mother noticed some white spots in her mouth before the rash appeared. The child has been lethargic, irritable and had a fever during this time. Upon checking her medical records, you find out that she has not been vaccinated and has had chickenpox before. Which family of viruses is most likely responsible for causing this in the child?