Rotavirus

The Humane rotaviruses are occurring human virus of the genus Rotavirus ( family Reoviridae ). The name is based on the wheel-like structure (Latin rota = wheel ) of the viruses under the electron microscope. They were discovered in 1973 by Ruth Bishop in the small intestine biopsies of affected children. Rotaviruses are the most common cause of severe diarrhea. At clinically relevant diarrhea rotaviruses are represented with a proportion of 35 to 52%. In developing countries, in particular die due to inadequate medical care according to estimates by the World Health Organization, approximately 850,000 children a year in a rotavirus -induced dehydration. The detection of rotaviruses is a notifiable disease in Germany according to § 7 of the Infection Protection Act.

Rotaviruses are widespread in the animal kingdom. In veterinary medicine rotavirus infection of calves have great economic importance.

Structure of rotavirus

Human Rotaviruses are 76 nm RNA viruses with a double-shell icosahedral capsid. A virus envelope is not present. The genome consists of eleven segments of double-stranded RNA from 0.6 to 3.3 kb in length. Each of said segments encoding a viral protein. The segmentation of the genome, there is a possibility of Reassortantenbildung. In total there are seven human pathogenic species within the genus Rotavirus known, which include a number of serotypes. The species classification is complex and includes serotypes, sub-types, G -and P- types. In groups A to C eleven human pathogenic serotypes and subtypes are included.

Transmission and disease patterns

The Rotavirus infection is usually classic fecal-oral route, with contaminated food or drinking water contaminated in some countries can play a role. Your multiplication takes place in the apical enterocytes of the small intestinal villi. After an incubation period of one to three days, its clinical symptoms, often vomiting, followed by high fever and diarrhea to acute diarrheal diseases on. In severe disease the diarrhea can last for four to five days and water and perform the consequent loss of electrolyte dehydration, which can be potentially life threatening. The usual duration of the disease is six to eight days. Worldwide die from this viral disease each year up to one million children due to inadequate medical care.

Presumably, by the viral protein ( NSP4 ), which has properties of an enterotoxin, the effect is increased.

Diagnosis

The diagnostic investigation of rotavirus from the stool usually occurs by means of an immunoassay, with the specific antigen ( capsid protein ) can be demonstrated. As much viral antigen in stool is present in the acute phase of the disease, antigen tests often have poor analytical sensitivity, for the detection of rotaviruses is but sufficient for acute diarrhea. A longer-term excretion of the virus without acute signs of infection (especially with immunodeficiency ) can not be detected due to the small amount of antigen in these cases by antigen test.

For specific questions on Ausscheiderstatus or to determine the subtypes for epidemiological studies, RT- PCR can be used. Only rarely a classical virus isolation, RNA electrophoresis or nucleic acid hybridization reaction used. Very easy is to demonstrate the virus in stool by electron microscopy, as the rotaviruses are with their typical morphology easy to recognize.

Rapid tests for the detection of antigen are possible, but these are due to low sensitivity and insufficient specificity ( false positives ) limited recyclable. Serological methods for detection of specific antibodies against rotavirus have diagnostically irrelevant.

Epidemiology

Rotaviruses are distributed worldwide. By the end of the third year of life, most children ( > 90 %) had already undergone a rotavirus infection. During the first years of life are increasingly antibodies formed as a result of contacts with rotavirus. Earlier diseases may protect against disease again at a later reinfection with the same or other rotavirus types. In adulthood diseases occur mainly as traveler's diarrhea, with only about 20% of Reisediarrhoen caused by rotavirus. The most severe courses of disease are found in the age group between six months and two years. In temperate climates, rotavirus infections are mainly observed during the winter months, as the pathogen spread in the warm, dry climate of heated homes easier. Except in children severe disease by rotavirus infection in the elderly or immunocompromised patients can be reported.

As a precautionary measure compliance with general standards of hygiene serves.

Vaccination

An oral vaccine against rotavirus ( RotaShield by Wyeth Lederle ) was started in 1998 in the United States in the normal vaccination schedule, but withdrawn on 15 October 1999 after 76 cases of intussusception ( intussusception, Darmeinstülpung ) had occurred and indicated a possible association with vaccination been. After extensive clinical trials of rotavirus vaccines approved for children aged up to six months in Europe and the U.S. since the second quarter of 2006. A clinical study on Rotarix - 615 investigated Intussuszeptionen from Brazil and Mexico - was published in June 2011 in the New England Journal of Medicine. Although Manish Patel and his team from the Centers for Disease Control and Prevention in Atlanta in their case-control study konstatierten a slightly increased risk, they see a positive benefit-risk balance for both countries.

According to a study by the Australian Therapeutic Goods Administration of Rotarix showed up with a by a factor of 3.5 ( 0.7 to 10.1 ) were significantly increased rate, whereas for RotaTeq, a trend toward increased risk by a factor of 5.3 ( 1.1 -15.4 ) was found.

Gestured Harry Greenberg of Stanford University in the NEJM, the results to the effect that " Intussuszeptionen a principal risk of all rotavirus vaccines are " as both vaccines consist of live viruses. The hypothesis that vaccination even lower the incidence of Intussuszeptionen average is, but only to show yet.

Therapy

Compulsory registration

A rotavirus infection is notifiable in Germany according to § 6 and 7 of the Infection Protection Act.