The progeny viruses are released from the cell by lysis. Pathophysiology
The diarrhoea is caused by multiple activities of the virus. Malabsorption occurs because of the destruction of gut cells called enterocytes. The toxic rotavirus protein NSP4 induces age- and calcium ion-dependent chloride secretion, disrupts SGLT1 transporter-mediated reabsorption of water, apparently reduces activity of brush-border membrane disaccharidases, and possibly activates the calcium ion-dependent secretory reflexes of the enteric nervous system. Healthy enterocytes secrete lactase into the small intestine; milk intolerance due to lactase deficiency is a symptom of rotavirus infection, which can persist for weeks. A recurrence of mild diarrhoea often follows the reintroduction of milk into the childs diet, due to bacterial fermentation of the disaccharide lactose in the gut. Diagnosis
Diagnosis of infection with 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 childs stool by enzyme immunoassay. There are several licensed test kits on the market which are sensitive, specific and detect all serotypes of rotavirus A. Other methods, such as electron microscopy and PCR, are used in research laboratories. Reverse transcription-polymerase chain reaction (RT-PCR) can detect and identify all species and serotypes of human rotavirus. Prevention
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.
The experience provoked intense debate about the relative risks and benefits of a rotavirus vaccine. In 2006, two new vaccines against rotavirus A infection were shown to be safe and effective in children, and in June 2009  the World Health Organization recommended that rotavirus vaccination be included in all national immunisation programmes to provide protection against this virus. Other animals
Rotaviruses infect the young of many species of animals and they are a major cause of diarrhoea in wild and reared animals worldwide. As a pathogen of livestock, notably in young calves and piglets, rotaviruses cause  economic loss to farmers because of costs of treatment associated with high morbidity and mortality rates. These rotaviruses are a potential reservoir for genetic exchange with human rotaviruses. There is evidence that animal rotaviruses can infect humans, either by direct transmission of the virus or by contributing one or several RNA segments to reassortants with human strains. References
Further reading
Ramig, RF (October 2004). "Pathogenesis of intestinal and systemic rotavirus infection". Journal of Virology. 78 (19): 10213–20. doi:10.1128/JVI.78.19.10213-10220.2004. PMC 516399. PMID 15367586. External links
WHO Rotavirus web page
CDC About Rotavirus