A 10-month-old infant presents to the emergency department with a 2-day history of watery diarrhea, vomiting, and fever. The parents report that the child has had seven episodes of diarrhea and four episodes of vomiting. The child has decreased oral intake and appears irritable and lethargic. Physical examination reveals sunken eyes, dry mucous membranes, and poor skin turgor. The child has not received vaccination for this preventable disease. What is the most likely causative organism for this infant’s condition?
