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Rotaviruses are a genus of viruses belonging to the Reoviridae family. Seven major groups have been identified, three of which (groups A, B, and C) infect humans, with group A being the most common and widespread one.
Vomiting and DiarrheaThey cause vomiting and diarrhea and are the most common cause of severe diarrhea in children, killing about 600,000 children every year in developing countries (as of 2005). New vaccines have been shown to be safe and effective in 2006. Rotaviruses cause acute gastroenteritis. "Infantile diarrhea", "winter diarrhea", "stomach flu", "acute nonbacterial infectious gastroenteritis", and "acute viral gastroenteritis" are other names applied to this disease.
Rotavirus gastroenteritis is a self-limiting, mild to severe disease characterized by vomiting, watery diarrhea, and low-grade fever. The infective dose is presumed to be 10-100 infectious viral particles. Because a person with rotavirus diarrhea often excretes large numbers of virus (108-1010 infectious particles/ml of feces), infection doses can be readily acquired through contaminated hands, objects, or utensils.
Asymptomatic rotavirus excretion has been well documented and may play a role in perpetuating endemic disease.
Incubation periodThe incubation period ranges from 1-3 days.
Symptoms often start with vomiting followed by 4-8 days of diarrhea.
Temporary lactose intolerance may occur. Recovery is usually complete. However, severe diarrhea without fluid and electrolyte replacement may result in death.
MortalityChildhood mortality caused by rotavirus is relatively low in the U.S., with an estimated 100 cases/year, but reaches over 500,000 cases/year worldwide (as of 2005). Association with other enteric pathogens may play a role in the severity of the disease.
Who gets rotavirus?Humans of all ages are susceptible to rotavirus infection.
Children 6 months to 2 years of age, premature infants, the elderly, and the immunocompromised are particularly prone to more severe symptoms caused by infection with group A rotavirus.
Group A rotavirus is endemic worldwide. It is the leading cause of severe diarrhea among infants and children, being responsible for about 20% of cases, and accounts for about half of the cases requiring hospitalization. Almost every child has been infected with rotavirus by age 5. Over 3 million cases of rotavirus gastroenteritis occur annually in the U.S. In temperate areas, it occurs primarily in the winter, but in the tropics it occurs throughout the year. The number attributable to food contamination is unknown.
Group B rotavirus, also called adult diarrhea rotavirus or ADRV, has caused major epidemics of severe diarrhea affecting thousands of persons of all ages in China. In a group B epidemic in China in 1982, more than a million people were affected.
Group C rotavirus has been associated with rare and sporadic cases of diarrhea in children in many countries. However, the first outbreaks were reported from Japan and England.
About 120 million rotavirus infections occur every year, causing the death of 600,000 to 650,000 children.
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