ROTAVIRUS INFORMATION

Rotavirus is a genus of viruses belonging to the family Reoviridae. There are seven groups, three of which (Group A, B and C) infect humans. Group A is the most common and most widespread, causing 90% of infections.

They cause vomiting and diarrhea are the most common cause of severe diarrhea in infants, causes approximately 55,000 hospitalizations each year in the United States and kills about 600,000 children each year in developing countries. New vaccines have proven effective and safe in 2006. Virtually all children under five years have been infected by rotavirus.

They are transmitted by the fecal-oral route, infecting cells of the small intestine, causing gastroenteritis can lead to diarrhea and even dehydration. Through the viral protein (NSP4), which possesses the characteristics of an enterotoxin, is further reinforced this effect diarrhea.1 Although producer were discovered in 1973 and are responsible for more than 50% of hospital admissions of children with severe diarrhea, are still underestimated by the medical community, especially in developing countries. Besides infect humans, they also affect some animals and is a pathogen for cattle.

Microbiology

Types of Rotavirus

There are seven species rotavirus, designated A, B, C, D, E, F and G. Humans are infected by types A, B and C, mainly by A. All species attack any animal. In type A there are variations, called serotypes. As with the influenza virus, using a dual system of classification, based on two types of capsid proteins. The glycoprotein VP-7 defines the type G and protease-sensitive protein VP-4 defines the type P. The type P is defined as a number for serotype P and as a number in brackets for genotype P. G serotypes have a nomenclature similar, with the number of serotype G the same genotype G. For example, the chain is denoted as Wa P1A [8] G1.
Structure

Rotavirus (from Lat. Broken: wheel) have a characteristic appearance similar to a wheel, when viewed by electron microscopy. Rotaviruses are non-enveloped viruses (naked), capsid observed in 3 layers (outer, middle and inner). The genome is composed of 11 segments of double-stranded RNA, which code for six structural proteins and six nonstructural (one of its segments encodes two proteins). The virus is stable in the environment. May reach 76.5 nm in diameter.

Proteins

The virion is composed of six proteins (VP). These are called structural proteins VP1, VP2, VP3, VP4, VP5 and VP6. Apart from the structural proteins, there are six more non-structural (NSP), produced only in infected cells. They are called NSP1, NSP2, NSP3, NSP4, NSP5 and NSP6. At least six of the twelve proteins encoded by the viral genome RNA are associated, and the function of these proteins in rotavirus are not fully explained, are believed to be involved in RNA synthesis and packaging, transport of the mRNA into the area genome replication and translation of mRNA and the regulation of gene expression.

Structural proteins

VP1 is located in the core of the virus and is an RNA polymerase. In an infected cell produces mRNA transcripts to synthesize viral proteins and genome doubled to produce new virus particles.

VP2 is part of the innermost layer of the virion and is attached to the RNA genome.

VP3 is also part of the inner layer of the virion and is an enzyme called guanylyl transferase. Is an enzyme that produces the cap 5 'RNA (capping enzyme), during post-transcriptional modification of mRNA. This cap stabilizes the 5 'end of messenger and prevents it from being attacked by nucleases, enzymes which degrade nucleic acids.

VP4 is located in the outer part of the virion and forms a protuberance, which is capable of binding to cellular receptors of the cell to enter inside. VP4 must be modified by an intestinal protease, to yield VP5 * and VP8 *, before the virus particle is infectious. VP4 structure determines the virulence of the virus and which is of type P

The VP6 is the major capsid protein. Is highly antigenic and may be used to determine the species of rotaviruses. It is used in clinical trials to determine the existence of rotavirus A.

VP7 is a glycoprotein that is part of the outer layer of the virion. Apart from their structural functions, determines the type G of the chain, and together with VP4, is involved in the immune response to virus.

NSP
NSP1 is transcribed from the gene 5 and is a nonstructural protein RNA binding.

NSP2 is an RNA binding protein that accumulates in cytoplasmic inclusions (viroplasm) and is necessary for genome replication.

NSP3 is joined to the mRNA in the infected cells and is responsible for the completion of cellular protein synthesis.
NSP4 is a viral enterotoxin that induces diarrhea and was the first viral enterotoxin was discovered.

NSP5 is encoded by the viral genome segment 11 of rotavirus A, and in infected cells is accumulated in the viroplasm.

NSP6 is a binding protein nucleic acid is encoded by gene 11, into an open reading frame offset.

Rotavirus Infections

The nature of the disease

Rotavirus gastroenteritis and foster strong abdominal pain. "Infantile diarrhea", "winter diarrhea", "nonbacterial acute infection" and "acute viral gastroenteritis" are the other names he is called to this condition. The infective dose is presumed to be of 10-100 infectious viral particles, since a person with rotavirus often excreted a large amount of viral particles: in the order of (108-1010 infectious particles / ml feces). The route of infection is through contact with hands or objects contaminated utensils. The incubation period for rotavirus disease is approximately 2 days. The disease is characterized by vomiting and watery diarrhea 3 to 8 days, and fever with abdominal pain occur frequently. Immunity occurs after infection. Infections tend to be less severe than the original infection.

Prognosis and prevention

Usually the development of the infection resolves spontaneously. Severe dehydration due to diarrhea is one of the major complications. We recommend the use of electrolytes, but should first consult the doctor.

The best defense is to use clean utensils and wash hands after leaving the baño.También be careful when handling diapers do not promote a subsequent infection.

Vaccines

In 2006, two rotavirus vaccines were shown to be safe and effective in children: Rotarix developed by GlaxoSmithKline and is created based on live attenuated and RotaTeq developed by Merck and is created with human and bovine recombinant viruses. Both are administered orally and live attenuated viruses. In 2006, the FDA approved RotaTeq for use in the United States and announced a price of 187.50 for the standard regimen of three doses. It is therefore one of the most expensive childhood immunization, despite the discount becomes an option unavailable to third infants world.and But WHO strongly recommends the inclusion of the rotavirus vaccine to immunization programs in all regions of the world. A previous vaccine, RotaShield developed by Wyeth-Ayerst, was withdrawn from the market in late 90's when it was discovered in rare cases be linked to severe complications of type-intestinal occlusion.

Complications

Repeated rotavirus infections may increase the risk of Celiac disease in children usually susceptible. Always believed that intestinal infections contribute to its development, a common digestive disorder triggered by eating wheat-based products and other foods containing gluten protein. Some studies, however, have reviewed the role of specific infectious agents in disease development. As participants in a study of environmental agents of disease desatadores, 1931 children in the Denver metropolitan area who were genetically susceptible to celiac disease, were monitored from infancy to verify whether they had experienced rotavirus and later development of celiac disease as well.

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