A 1-year-old child develops voluminous watery diarrhea and vomiting. She is brought to the pediatrician by her parents and evaluated, then sent home with instructions for the parents to give the child an electrolyte replacement solution. Which of the following viruses is the most likely cause of the child's diarrhea?

Rotavirus is the major cause of diarrhea in infants and children under the age of 2. The replicates in the intestinal mucosa, producing a profuse, watery, non-bloody diarrhea, often coupled with nausea and vomiting. Transmission is by the fecal-oral route. Coronaviruses usually cause cold-like illnesses. Lymphocytic choriomeningitis virus can cause headache, malaise, myalgia, conjunctivitis, and, occasionally, meningitis. Norwalk agent can also cause diarrhea, but usually affects patients older than 2 years. Ref: Brooks G.F. (2013). Chapter 37. Reoviruses, Rotaviruses, and Caliciviruses. In G.F. Brooks (Ed), Jawetz, Melnick, & Adelberg's Medical Microbiology, 26e.