الفهرس 
Classification of Rotaviruses
Structural ProteinsOnly 14 pages are availabe for public view
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Abstract
Rotavirus has remained a consistent and significant cause of gastroenteritis diarrhoea since its identification in 1973. Worldwide, rotavirus is associated with 5 percent of deaths in children younger than 5 years. The highest incidence of deaths is found in developing nations of Asia, Africa, and the Americas. The incidence of disease is staggering. Each year, rotavirus causes approximately 111 million episodes of gastroenteritis requiring home care, 25 million clinic visits, million hospitalizations, and approximately 500,000 deaths.
All children around the world, regardless of economic or geographic boundaries, become infected with rotavirus in the first few years of life. The disease in the majority of children is mild to moderate and self-limited. Once infected, natural immunity generally prevents children from acquiring subsequent episodes of severe rotavirus diarrhea, but asymptomatic or mildly symptomatic re-infection is common. However in 10 to 20 percent of the infected children, the diarrhea will be severe enough to require medical attention. When available, oral rehydration therapy is usually effective in treating acute watery diarrhea, but in some cases of severe dehydration, hospitalization with intravenous rehydration may be required.
Rotavirus infection is spread primarily by the fecal-oral route. After ingestion, the rotavirus particles are carried to the small intestine where they infect the mature enterocytes in the mid and upper part of the villi of the small intestine, leading to diarrhoea. Rotaviruses induce a clinical illness characterized by vomiting, diarrhea, abdominal discomfort, fever, and dehydration that occurs primarily in infants and young children. The highest attack rate is usually among infants and young children 6 to 24 months old. However in the infected children, the diarrhea will be severe enough to require medical attention. Deaths from rotavirus gastroenteritis may occur from dehydration and electrolyte imbalance.
Rotavirus is classified as a genus in the family Reoviridae. The rotavirus genus currently has five species (Rotavirus A to Rotavirus E), with two possible additional species (Rotavirus F and Rotavirus G). The intact virion is about 60 – 80 nm in diameter and is characterized by a distinctive triple-layered capsid. The inner capsid encompasses the core containing the virus genome. The genome consists of 11 segments of dsRNA, which encodes six structural and six nonstructural proteins. The members of each species share a common group antigen located in the middle layer of the mature viral particle (VP6). Fecal-oral rout and person-to-person spread through contaminated hands is the most important means by which rotaviruses are transmitted.
The laboratory diagnosis of rotavirus infection is based either on the direct isolation of organism by culture which is insensitive, difficult to perform and time consuming or its Ag detection in stool using EM and serological (EIA, LA) or molecular genetic techniques (RT-PCR, PAGE). Other diagnosis is done indirectly by the detection of its specific antibodies in serum using serological techniques (IEM, CF, HAI, and EIA).