Molecular detection and characterization of sapovirus in hospitalized children with acute gastroenteritis in the Philippines

Background: Human sapovirus (SaV) is a causative agent of acute gastroenteritis. Recently, SaV detection has been increasing worldwide due to the emerging SaV genotype I.2. However, SaV infection has not been reported in the Philippines. Objectives: To evaluate the prevalence and genetic diversity of SaV in hospitalized children aged less than 5 years with acute gastroenteritis. Study design: Stool samples were collected from children with acute gastroenteritis at three hospitals in the Philippines from June 2012 to August 2013. SaV was detected by reverse transcription real-time PCR, and the polymerase and capsid gene sequences were analyzed. Full genome sequencing and recombination analysis were performed on possible recombinant viruses. Results: SaV was detected in 7.0% of the tested stool samples (29/417). In 10 SaV-positive cases, other viruses were also detected, including rotavirus (n=6), norovirus (n=2), and human astrovirus (n=2). Four known SaV genotypes (GI.1 [7], GI.2 [2], GII.1 [12], and GV [2]) and one novel recombinant (n=3) were identified by polymerase and capsid gene sequence analysis. Full genome sequencing revealed that the 5[U+02B9] nontranslated region (NTR) and nonstructural protein region of the novel recombinant were closely related to the GII.1 Bristol/98/UK variant, whereas the structural protein region and 3[U+02B9] NTR were closely related to the GII.4 Kumamoto6/Mar2003/JPN variant. Discussion and conclusions: SaV was regularly detected in hospitalized children due to acute gastroenteritis during the study period. A novel recombinant, SaV GII.1/GII.4, was identified in three cases at two different study sites.