Rotavirus

Medical Virology
Rotavirus: Dr. Jawad Kadhum Tarrad

Important properties:
• It is belong to family Reoviruses.
• Non-envelope(naked).
• Surrounded by double-layer icosahedral capsid.
• Genome is consist of 11 segments of dsRNA.
• It has several outer surface proteins(aka: viral hemagglutinin), and it divided into 7 serogroups(A-G).
Transmission:
It is transmitted by fecal-oral route. Massive shedding of virus occur in stool during diarrhea. Many animals are infected ,but these are not source of human disease.
Replication:
Virus attaches to surface of epithelial cell of small intestine at site of beta-adrenergic receptor. After entry of virion into cytoplasm of cell, RNA polymerase synthesize mRNA from each of 11 segments . The 11 segments of mRNA are translated into viral proteins. dsRNA are synthesized by RNA polymerase. Complete virions are released from infected cell by lysis (not by budding)|.
Path.
Virus infects villi of mucosa in small intestine, then replicates in cytoplasm of epithelial cell. NSP4(non-structural protein) act as viral enterotoxin ,resulting in inability of small intestine to re-absorption and decreased production of digestive enzymes. Excess secretion of fluid and electrolytes into bowel lumen, consequent loss of salt(Na), glucose and water lead to watery diarrhea(non-bloody).
Intestinal sIgA protects against re-infection, and colostrums IgA protect neonates up to age of 6 months.
C/F:
Rotavirus is most common cause acute viral gastroenteritis ,primarily in infants and young children. After IP(1-3 days) , the acute gastroenteritis disease is characterized by sudden onset , fever , nausea, vomiting watery diarrhea lasting 4-5 days, dehydration due to electrolytes imbalance. Rotavirus infects all age groups , peak incidence in 6-24 months. The disease is most serious and more severe in infants, children under 2 years develop mild disease. Adults usually have minor symptoms.
Epidemiology:
Rotavirus infection occurs worldwide. Acute gastroenteritis is very common with significant public health. It causes high morbidity and mortality in children, estimates range from 3-5 billion cases annually in children under 5 years of age resulting in 3-5 million death( 1 million death in infants).The rotavirus infection usually predominate during winter season. 50% of acute gastroenteritis of hospitalized children are caused by rotavirus.