PRINCE GEORGE'S COUNTY, Md. (DC News Now) -- Officials confirmed a case of measles at a Montessori school in Oxon Hill Friday, potentially exposing its young students, faculty, and staff to the highly contagious disease. In a letter sent to parents, guardians, and staff Thursday, John Hanson Mont essori Principal Courtney M. King said the last date of exposure in the school was March 12. Due to privacy guidelines, she could not confirm information about the person who tested positive - including whether they are a student or teacher. DC, Virginia health officials warn about potential measles exposure after cases confirmed in Maryland Students at John Hanson Montessori are in Pre-K through Middle School (grades six through eighth). In the letter, King noted that people who have been vaccinated for Measles (MMR) are at an extremely limited risk of contracting the disease. Unvaccinated people, however, face a significantly higher risk of infection and complications, Prince George's County Public Schools (PGCPS) said. Measles typically begins with a high fever and cold-like symptoms, including a cough, runny nose, and red, watery eyes. Then, people develop a red rash that may look like small bumps and could last for five to six days. As a precaution, any unvaccinated student or staff member at John Hanson Montessori will be excluded from in-person learning or work for 21 days. Despite the "serious concern" caused by measles, PGCPD Superintendent Millard House II reminded parents that the flu season is still ongoing. In the past season, the Prince George's County community has experienced two flu-related deaths. Family remembers 10-year-old who died from flu in Prince George’s County "This serves as a sobering reminder of the importance of protecting our health and taking steps to prevent the spread of illness," House stated. Just last month, 10-year-old Minka Greene - who attended John Bayne Elementary School in Capitol Heights - passed away from the flu. PGCPS officials urged parents to notify a school nurse (301) 749-4052 if they or their children have been diagnosed with measles. They should then stay home and contact the Prince George's County Health Department at (301) 583-3750. Though school officials have taken measures to slow the spread of illness, House urged parents to ensure their children are up to date on their immunizations and to keep them home if they are not feeling well. ...read more read less