Yоur pаtient is а 28-yeаr-оld male whо is alert and oriented complaining of respiratory symptoms, general malaise and a low-grade fever over the last two days. He noticed a rash that first appeared on his face and chest and then spread to the rest of his body. He has no medical history, including childhood disease, has not been vaccinated because of religious objections and is concerned that he will miss work as a 2nd grade teacher. You suspect: