**1. Introduction**

Higher cases of diarrhea are seen in developing countries. In which 14% of children aged fewer than five years had diarrhea, reported in a health survey of Nepal Demographic 2011. During the last three years, diarrhea cases in Nepal were increasing with time. It is estimated that out of 1000 children, 528–629 children are affected by it. During 2013–2014, in Nepal, 36 children per 1000 under less than five years of age die due to this infection [1]. In 2015, 9% of children less than five years of age are affected by diarrhea worldwide 1400 children are died due to it each day and annually 530,000 children are died due to it. Death rates of diarrhea are high in less than two years of children in Asia and Africa [2].

In Ethiopia, it is a very serious health problem for children in the region. In 2011, 13% of Children, less than five years of age were affected by this disease [3] 24–30% of the infant died due to diarrhea in this country [4]. The Ethiopian region is the very poorest region in the world and shows a high mortality rate of diarrhea [5] 15% of children having an age of fewer than five years are died due to it in developing countries. Acute diarrhea is a major cause of health problems worldwide. In 1973, rotavirus was the first time introduced as the cause of diarrhea when it was collected from epithelium cells of the upper villi surface in the gastrointestinal tract. Rotavirus was first seen in electro micrograph in 1973 and the word rotavirus has an origin from the Latin word, which means wheel-like. At the end of 1973, many types of research were conducted by doctors to determine the virus that caused diarrhea in infants and young children [6].

In the same year, the first-time rotavirus was identified in humans, when the first child is admitted to the hospital due to acute diarrhea. It was present in the cytoplasm of duodenal epithelial cells [7]. In Pakistan every year one child dies due to diarrhea. 400,000 infants die in his/her first years of life, published in the annual report in 2011 of Pakistan Medical Association. Acute diarrhea is a major problem in most developing countries. Most children remain under the threat of acute diarrhea infection during the first five years of life. It is estimated that 4.6 million deaths of children occurred annually in which acute diarrhea is the main factor of 25–30% of death of children aged less than five years [8]. 1.7 million children are infected by diarrhea worldwide, according to the world health organization. 760,000 mortalities of children occur each year due to diarrhea, which is why it is considered as the second major cause of death in children aged less than five years [9, 10].
