Rotavirus
Date: 2 سال قبل
author: AmirAbad
Rotavirus
Rotavirus is
a genus of double-stranded RNA viruses in
the family Reoviridae. Rotaviruses are the most common cause
of diarrhoeal disease among infants and young children. Nearly
every child in the world is infected with a rotavirus at least once by the age
of five. Immunity develops with each infection, so subsequent
infections are less severe; adults are rarely affected.[3] There are
nine species of the genus, referred to as A, B, C, D, F, G, H, I and
J. Rotavirus A, the most common species, causes more than 90% of rotavirus
infections in humans. Rotavirus E, which is seen in pigs, has not
been confirmed as a distinct species.
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).
Signs
and symptoms
Rotaviral
enteritis is a mild to severe disease characterised
by nausea, vomiting, watery diarrhoea and low-grade fever. Once
a child is infected by the virus, there is an incubation period of
about two days before symptoms appear. The period of illness is acute.
Symptoms often start with vomiting followed by four to eight days of profuse
diarrhoea. Dehydration is more common in rotavirus infection than in
most of those caused by bacterial pathogens, and is the most common cause of
death related to rotavirus infection.
Disease
mechanisms
Rotaviruses
replicate mainly in the gut, and infect enterocytes of
the villi of the small intestine, leading to structural and
functional changes of the epithelium. There is evidence in humans,
and particularly in animal models of extraintestinal dissemination of
infectious virus to other organs and macrophages.
The
diarrhoea is caused by multiple activities of the virus.
Diagnosis
Diagnosis
of infection with a rotavirus normally follows diagnosis
of gastroenteritis as the cause of severe diarrhoea. Most children
admitted to hospital with gastroenteritis are tested for rotavirus
A. Specific diagnosis of infection with rotavirus A is
made by finding the virus in the child's stool by enzyme
immunoassay. Other methods, such as electron
microscopy and PCR (polymerase chain reaction), are used in
research laboratories. Reverse transcription-polymerase chain reaction
(RT-PCR) can detect and identify all species and serotypes of human
rotaviruses.
Treatment
and prognosis
Treatment
of acute rotavirus infection is nonspecific and involves management of symptoms
and, most importantly, management of dehydration. If untreated,
children can die from the resulting severe dehydration.Rotavirus infections
rarely cause other complications. Probiotics have been shown to
reduce the duration of rotavirus diarrhoea.
Prevention
Rotaviruses
are highly contagious and cannot be treated with antibiotics or other drugs.
Because improved sanitation does not decrease the prevalence of
rotaviral disease, and the rate of hospitalisations remains high despite the
use of oral rehydrating medicines, the primary public health intervention is
vaccination.
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