Detection rate, clinical characteristics, and molecular characterization of enterovirus and parechovirus infections in Thai infants during the first three months of life

OBJECTIVES: To determine the detection rate, molecular characteristics, and clinical features of enterovirus and parechovirus infections in young infants with sepsis-like illness. METHODS: A prospective study conducted from September 2023 to February 2025 at four Thai tertiary hospitals enrolled infants aged 0-3 months with sepsis-like symptoms who underwent routine laboratory tests and real-time reverse transcription polymerase chain reaction for enterovirus, human rhinovirus, and parechovirus. RESULTS: Of 56 infants with sepsis-like illness, 15 tested positive (26.8%; 95%CI 17.0-39.6%) for enterovirus, human rhinovirus, or parechovirus. Detected viruses included echovirus 3 and 9 (n = 3), human rhinovirus types A, B, and C (n = 8), coxsackievirus A6 and B3 (n = 2), and parechovirus type 3 (n = 2). Virus-positive infants had a higher median age than virus-negative infants (39 vs. 15 days, p = 0.004), and neonates ≤ 1 month of age were usually virus-negative (p = 0.03). Virus-positive infants older than one month were more likely to have a temperature ≥ 37.5 °C (p = 0.03). Cough was more common in virus-positive infants, while abdominal distension was more frequent in virus-negative infants (p = 0.04). CONCLUSION: Enteroviruses were commonly detected in Thai infants with sepsis-like illness, with most positives attributable to enterovirus/rhinovirus group viruses, whereas parechovirus was infrequent and limited to HPeV3. Genotyping indicated established circulating lineages.