- Viruses in the family Reoviridae
- spherical, nonenveloped particles
- have an icosahedral structure. (MCQ)
- consists of 10 to 12 segments of double-stranded (ds) RNA. (MCQ)
- The virions contain all the enzymes needed to make positive-strand RNA transcripts, which are capped and methylated.
- Reoviruses replicate completely in the cytoplasm.
- The name “reovirus” stands for respiratory and enteric orphan virus..
- a characteristic morphology– appearance of wheels with spokes radiating from the center and a smooth outer rim (MCQ)
- The particles also have a large number of channels connecting the outer surface of the virion to the inner core
- These channels are necessary because viral replication in the cytoplasm occurs without complete uncoating of the virion particle.
- Rotaviruses are divided into seven serogroups (A through G)
- group A is the most important cause of outbreaks of disease in humans.
- Transmission is via the fecal–oral route.
- account for about 50 percent of cases of severe diarrhea in infants and young children (up to age 2 years). (MCQ)
- Viral replication
- Undergo attachment to and uptake by the host cell
- Become partially uncoated in a lysosome.
- genome has 11 segments of linear, dsRNA, each of which codes for a single protein. (MCQ)
- Reassortment of the RNA segments can occur when a cell is infected with two different rotaviruses.
- The viral particles contain enzymes (such as RNA-dependent RNA polymerase) that are needed to synthesize positive-sense RNA transcripts with a 5′ cap. (MCQ)
- These positive RNA strands function not only as mRNA but also as templates for the synthesis of negative-strand RNA
- After the negative-strand RNA is made, it stays associated with its positive-strand template, giving rise to a dsRNA segment that is packaged in the virion.
- Rotaviruses are released following cell lysis rather than by budding through the membrane, thus accounting for the lack of a viral envelope. (MCQ)
- Clinical significance
- infect the epithelial cells of the small intestine, primarily the jejunum (MCQ)
- Rotaviruses are able to reach the small intestine because they are resistant to the acid pH of the stomach.
- The incubation period is usually 48 hours or less.
- Laboratory identification
- identification can be made by detection of viral capsid antigens in stool samples using enzyme-linked immunosorbent assay (MCQ)
- An increase in the titer of antiviral antibody in a patient’s serum can also be diagnostic. (MCQ)
- Treatment and prevention
- The most important clinical intervention is the rapid and efficient replacement of fluids and electrolytes, usually intravenously.
- Two oral vaccines using weakened live virus
- highly efficacious in protecting infants against severe rotavirus gastroenteritis
- not associated with increased risk of intussusception (MCQ)
Rotavirus is the most common cause of severe diarrhea among infants and young children. It is a genus of double-stranded RNA virus in the family Reoviridae. Nearly every child in the world has been infected with rotavirus at least once by the age of five. Immunity develops with each infection, so subsequent infections are less severe; adults are rarely affected. There are five species of this virus, referred to as A, B, C, D, and E. Rotavirus A, the most common species, causes more than 90% of rotavirus infections in humans.
The virus is transmitted by the faecal-oral route. It infects and damages the cells that line the small intestine and causes gastroenteritis (which is often called “stomach flu” despite having no relation to influenza). Although rotavirus was discovered in 1973 and accounts for up to 50% of hospitalisations for severe diarrhoea in infants and children, its importance is still underestimated within the public health community, particularly in developing countries. In addition to its impact on human health, rotavirus also infects animals, and is a pathogen of livestock.
Infección Gastrointestinal por Rotavirus
Realización Audiovisual: Walter Waymann – Dirección de Contenidos: Ana María Campos – Producción Académica: Dr. Jonas Chnaiderman – Desarrollo de Contenidos: María Carmen Molina (Programa de Inmunología), Germán Hermosilla, Gonzalo Osorio, María Teresa Ulloa (Programa de Microbiología y Micología), Aldo Gaggero, Carmen Larrañaga (Programa de Virología) – Banda de Sonido Original: Christian Waymann – Unidad de Animación e Ilustración Científica – ICBM – Facultad de Medicina – Universidad de Chile.
To all parents in the world, vaccines are safe and protective for your children. Rota virus is one of the vaccine preventable diseases that can be easily get ride of the risk being infected with by vaccination. Whatever someone says about the vaccine safety, go to the reliable sources like CDC, NIH, and WHO to get the correct information.