Several authors have tested the efficacy of immunoglobulin preparations with antibody activity against human rotavirus as a means of providing passive immunity to children. For example, children consuming a defatted colostrum preparation from cows immunized against a strain of human rotavirus had no improvement of symptoms when the infection was established (patients admitted to a hospital with rotavirus infection), however the preparation was effective in limiting diarrhea in children when consumed prior to the infection [56, 57] . In another study, cessation of excretion of rotavirus in the stool of infants with acute rotavirus gastroenteritis was correlated with the presence of neutralizing activity in the stool after ingestion of a bovine whey protein concentrate from rotavirus-hyperimmunized cows [58] , although there was not a significant decrease in duration of diarrhea in that study. Other studies have found that treatment of children with hyperimmune bovine colostrum from cows immunized with human rotavirus serotypes reduces the duration and severity of diarrhea due to rotavirus [59] , and can provide significant protection from rotavirus infection [60] .