Asymptomatic Adults and Children Can Transmit Human Parechoviruses and Enteroviruses to Neonates and Young Infants

BACKGROUND: Human parechovirus (HPeV) type 3 and enteroviruses (EVs) are the common viruses causing severe diseases in neonates and young infants. Given no specific therapy is currently available and the morbidity and mortality of the diseases are high, understanding the detailed transmission routes is critical for the prevention. METHODS: This prospective study evaluated viral etiologies of neonates and young infants < 4 months suspecting sepsis and/or meningoencephalitis in 2016 in Niigata, Japan. DNA and RNA from serum/cerebrospinal fluid (CSF) were analyzed for HPeVs, EVs, and/or herpes simplex virus using real-time PCR. Bacterial infection was excluded based on blood/CSF culture results and their clinical course of the patients. To investigate the source of infection, we collected stool samples from available family members of the patients regardless of their symptoms. The stool samples were checked for each virus and if they were positive, the VP1 region for HPeVs and VP1/VP4-2 regions for EVs, were sequenced and typed. Furthermore, clinical information on symptomatic family members of HPeVs- and EVs-infected patients was compared. RESULTS: In total, 23/54 (43%) were positive for HPeVs (12/54, 22%) and EVs (11/54, 20%). Among the available family members for HPeVs and EVs, symptomatic family members were observed 28% (15/54) and 25% (13/53), and their stool samples were positive; 87% (13/15) and 100% (13/13), respectively. For available stool samples from asymptomatic family members, 36% (14/39) was positive for HPeV3 and 50% (20/40) were positive for EVs. Genetic sequence analyses confirmed the identical HPeVs and EVs; 92% (12/13) and 92% (12/13) in symptomatic patients, and 64% (9/14) and 70% (14/20) in asymptomatic patients, respectively. Rhinorrhea was the only symptom commonly observed in symptomatic family members infected with HPeVs (12/13, 92%) compared with those infected with EVs (4/13, 31%) (P = 0.004). CONCLUSION: Symptomatic, and even asymptomatic children and adults can be a source of HPeVs- and EVs-infected neonates and young infants. Careful hand hygiene and other standard precaution may contribute to decrease the risk of the transmission during the outbreak of HPeV3 and EVs. DISCLOSURES: All authors: No reported disclosures.