A state public health region reported 39 cases of meningitis…

A state public health region reported 39 cases of meningitis in children 15 years of age and younger to date this year. Seven of those children died. The total population of the region is 780,000, of whom 84,000 are children age 15 years old and younger. Only four cases of meningitis were reported in the public health region during the previous year. No other public health region in the state has an incidence of meningitis that is higher than expected for that region. Based on the information given, the relative frequency of meningitis in the region at this time can best be described using what term?