Acute diarrhoea is the most common death reason of children in poor countries and a severe children disease worldwide. The most common cause of the disease is rota virus originating from faeces due to poor hygiene. The best time for detecting rota virus in faecal sample is 2-5 days after the appearance of the symptoms, but the faeces will contain the virus for the whole long length of the disease. Infections are most common during winter and can create epidemics resulting in the illness of thousands of people. Typically, rota virus is found in 50 % of children needing hospital care due to stomach disease. The virus multiplies in cell nuclei and seems to be species specific as to symptoms created. Cultivation of rota virus is very difficult and useless as a diagnostic tool. Fortunately, rota virus detection directly from faeces is easy.
A great majority of diarrhoea cases not linked to rota virus are caused by adeno virus types Ad40 and Ad41. Adeno virus causes stomach disease worldwide in every season. The victims are generally children under 2-year age, but all people are vulnerable. 4-15 % of the stomach diseases needing hospital care, are caused by adeno virus.