## 1 Introduction  
Acute gastroenteritis (AGE) is one of the most common infectious diseases globally, affecting individuals across all age groups but disproportionately impacting young children and immunocompromised populations. AGE is characterized by symptoms such as diarrhea, vomiting, and abdominal pain, which can lead to significant morbidity and mortality, especially in resource-limited settings [1]. While mortality due to AGE has decreased in high-income countries due to advancements in healthcare and the introduction of vaccines, particularly for rotavirus, it remains a leading cause of child mortality in low-income regions [2]. Globally, rotavirus, norovirus, sapovirus, adenovirus, and astrovirus are among the most frequently identified viral agents causing AGE, each contributing to unique clinical and epidemiological patterns [3]. Rotaviruses (RVs), members of the Reoviridae family, are non-enveloped, double-stranded RNA viruses classified into 10 different species (A-J), with Rotavirus A being the leading cause of severe gastroenteritis in children under five years of age. They are responsible for over 200,000 deaths annually, predominantly in low-income countries. RV infects enterocytes in the small intestine, inducing diarrhea through mechanisms such as malabsorption due to enterocyte destruction, intestinal secretion stimulated by its enterotoxin (NSP4), and activation of the enteric nervous system. Despite widespread vaccination efforts since 2006, the effectiveness of live attenuated oral vaccines like Rotarix and RotaTeq remains suboptimal in low-income countries, likely due to factors such as environmental enteropathy and co-administration with other vaccines. Rotavirus infection can also manifest extra-intestually, with potential associations with conditions like encephalitis and biliary atresia, though its systemic effects are not fully understood [4]. Norovirus (NoV) is a non-segmented, positive-stranded RNA virus and a member of the Caliciviridae family. It has only a single species, Norwalk virus, which is divided into six genogroups and 30 genotypes. NoV is a highly infectious gastrointestinal virus, requiring as few as 10 viral particles to initiate infection, and spreads through fecal-oral transmission, contaminated food or water, and contact with infected individuals. Therefore, norovirus has worldwide distribution, frequently causing outbreaks in healthcare facilities, schools, and the food service industry. Genogroup II genotype 4 (GII4) strains dominate outbreaks due to their ability to rapidly evolve and escape herd immunity. While infections are typically self-limiting in healthy individuals, they can lead to severe complications in immunocompromised individuals, the elderly, and young children. Despite advances in understanding its pathogenesis, there is still no licensed vaccine available [5; 6; 7; 8]. Effective prevention strategies include rehydration therapy and hygiene measures, with ondansetron showing promise as an adjunct to oral rehydration by reducing vomiting, though it may increase diarrhea temporarily [9]. Sapoviruses (SaVs) are members of the Caliciviridae family and are emerging as significant causes of AGE, particularly in young children. First identified in an orphanage in Sapporo, Japan, SaVs are non-enveloped, positive-sense, single-stranded RNA viruses classified into five genogroups, with GI, GII, GIV, and GV infecting humans. Globally, SaVs have a pooled prevalence of 3.4% among children with AGE, with genogroup I (GI) and genogroup II (GII) strains being predominant. SaV infections are often associated with milder symptoms compared to norovirus or rotavirus. Given the increasing prevalence of SaVs and their significant role in NoV-negative AGE cases, there is a growing need for improved surveillance and vaccine development targeting the most prevalent genotypes [10; 11; 12; 13].