The patient was a 1-year-old male admitted to the hospital in December because of dehydration. His parents reported that he had a 1-day history of fever, diarrhea, emesis, and decreased urine output. On admission, his vital signs revealed a temperature of 39.5EC, slight tachycardia with a pulse of 126 beats/min, and respiration of 32/min. He was less interested in play than usual. His general physical examination was remarkable for dry mouth, decreased tears when crying and hyperactive bowel sounds. Urinalysis was significant for a high specific gravity and ketones (consistent with the patient's dehydration). Stool, blood, and urine samples were sent for culture. A stool sample was also checked for ova and parasites. There were no fecal leukocytes. The patient was given intravenous normal saline and had nothing by mouth. Over the next 48 h his emesis abated. Once he was rehydrated and was tolerating oral feedings, he was discharged home. All routine cultures gave negative results, but a rapid test for rotavirus in stool was positive.

1. What type of isolation should the patient be in while in the hospital? 
   

2. Why does rotavirus cause a watery diarrhea instead of a bloody diarrhea?
   

3. Describe the rapid test for rotavirus detection. 
   

4. What is the best treatment for rotavirus infection?
   

5. Can patients get this infection again?
   

6. Are other family members likely to acquire this infection?
   

7. Is there an effective vaccine to prevent illness? 
   

BACKGROUND

This child has a rotavirus infection. Rotavirus is a member of the family Reoviridae (double strand RNA viruses with segmented genomes). Group A rotavirus is the most common diarrheal pathogen seen in children less than 5-years-old in the United States. The clinical spectrum varies from asymptomatic infection to severe disease.

It generally is self-limited, lasting approximately 1 week in most cases. This disease is often referred to as "winter vomiting disease". It may be responsible for as many as 50% of pediatric hospitalizations during the winter. Characteristically, rotavirus illness occurs sporadically and not in widespread outbreaks. Group B rotavirus has caused a large outbreak of diarrheal disease in Chinese adults, but is very uncommon in the United States.

The differential diagnosis for acute diarrhea includes bacterial, parasitic, and viral etiologies of gastroenteritis. Because of the absence of fecal leukocytes, agents of invasive diarrhea such as Salmonella, Shigella, and Campylobacter spp. and Entamoeba histolytica are less likely, although certainly possible. The leading parasitic possibilities include Giardia and Cryptosporidium spp., especially if this child was in a day-care center. The viruses that can cause gastroenteritis include rotavirus (most frequent), enteric coronaviruses and unclassified small round viruses, Norwalk and Norwalk-like viruses, enteric adenovirus, calicivirus, and astrovirus. Norwalk virus infections can result in community outbreaks of diarrheal illness primarily in adults.