A fourth case of the measles has been confirmed by the Monroe County Health Department.
Health Department officials aren't disclosing the age, gender or the location of the patient, or if the individual had been vaccinated or not. They say they believe this is an isolated case and the risk of exposure to others is very low.
But it comes after three children -- a toddler and two students at the Spencerport School District -- came down with the measles. All three of the children were unvaccinated.
Those born before January 1st, 1957 or who have had two doses of the MMR vaccine are considered immune.