Background
Rotaviruses are the primary pathogens to cause non-bacterial acute gastroenteritis and diarrhea, especially in children from 6 months to 2 years of age, premature infacts, the elderly, and the immunocompromised. Rotaviruses have been identified in almost 40% of the feces of children with gastroenteritis. Rotavirus is the cause of up to 50% of the hospitalized cases of diarrhea in infants and young children; over 3 million cases of rotavirus gastroenteritis occurs annually in the U.S and 120 million infections worldwide. Studies also indicate that a high frequency of rotavirus infections may increase the risk of celiac disease autoimmunity in children with genetic predisposition.
Rotaviruses have a genome consisting for 11 double-stranded RNA segments surrounded by a distinctive three-layered icosahedral protein capsid. The first layer is formed by the protein VP2, with each vertex having a copy of the proteins VP1 and VP3. The second layer is formed by the protein VP6. The outermost protein layer is composed of the structural glycoprotein VP7 and the spike protein VP4. Viral particles are up to 100nm in diameter and have a buoyant density of 1.36 g/mL in CsCl.
Rotaviruses tend to affect gastrointestinal epithelial cells that are at the tip of the villus. Their triple protein coats make them very resistant to the normally prohibitive pH of the stomach, and also digestive enzymes (lipases and proteases) in the gastrointestinal tract. during the infection, rotavirus produces mRNA to support both protein translation and genome replication.
Rotavirus transmission is by oral-fecal contact with an incubation period of 1-3 days. Characteristic symptoms include vomiting, hydrodiarrhea for 3-8 days, high temperature, and stomach pains. A large amount of rotavirus particles are shed during infection.
Specific diagnosis of the rotavirus infection is made by identification of the virus in the patient's stool. Enzyme linked immunosorbent assay (ELISA) is the test most widely used to screen clinical specimens. Electron microscopy and polyacrylamide gel electrophoresis are used in some laboratories in addition or as an alternative to ELISA.
