An 18-month old developed acute gastroenteritis with fever and watery diarrhea that lasted 10 days. She had been vaccinated against rotavirus at 2 and 4 months of age as recommended. Eight days later, both of her brothers, ages 3 and 6, developed acute gastroenteritis. Which of the following tests would most likely reveal the etiologic agent of their gastroenteritis?
Culture for Norovirus DFA for enterovirus on intestinal biopsy EIA for adenovirus 40/41 EM examination of stool for astrovirus