A 7 month old girl presented with a rash which started behin…

A 7 month old girl presented with a rash which started behind her ears, fever and cough of one day duration. She missed her 6 months immunization. On examination she has conjunctivitis and an erythematous maculopapular rash over her entire body. Her eyes are dry and without tears. To make the definitive diagnosis of her acute infection the following specimen should be obtained: