Molecular detection, phylogenetic characterization, and inflammatory biomarkers of human torovirus in iraqi children with acute gastroenteritis

Human torovirus (HToV) is a recognized enteric pathogen associated with acute gastroenteritis, yet information regarding its circulation, molecular characteristics, and genetic diversity remains limited, particularly in developing countries. A total of 200 stool samples were collected from pediatric patients admitted to a tertiary care hospital in Baghdad, Iraq, between December 2023 and August 2024. Viral RNA was detected using one-step real-time RT‒qPCR. Selected positive samples were further analyzed by conventional RT‒PCR targeting the nucleocapsid (N) gene, followed by Sanger sequencing and phylogenetic analysis. HToV RNA was detected in 40 (20%) of the samples. The most common clinical manifestations among HToV-positive patients were watery diarrhea (100%), abdominal pain (100%), fever (85%), and vomiting (77.5%). Compared with HToV-negative gastroenteritis patients, HToV-positive gastroenteritis patients showed increased lymphocyte percentage and platelet count, accompanied by decreased neutrophil percentage and hemoglobin level. Serum IFN-γ, IL-6, and CRP levels were significantly elevated in infected children. Sequence analysis demonstrated approximately 99% nucleotide identity with previously reported HToV reference strains, whereas lower nucleotide similarity was observed with animal-derived Torovirus strains. Phylogenetic analysis revealed that the Iraqi isolates clustered with previously reported HToV lineages. This study provides the first molecular and sequence-based characterization of HToV among Iraqi pediatric patients with acute gastroenteritis. The analyzed HToV isolates showed a high degree of nucleotide conservation within the partial nucleocapsid (N) gene. HToV-positive children exhibited distinct hematological and immunological alterations compared with HToV-negative children with acute gastroenteritis, although these findings should be interpreted with caution because other enteric viruses were not investigated. These results support the inclusion of HToV in routine molecular surveillance.