Methods: We first determined the sensitivity and quantitative capability of NGS by comparing the NGS-determined number of sequences of human herpesvirus-6 (HHV-6) in clinical serum samples with the HHV-6 load measured using real-time PCR. HHV-6 was measured as it occasionally causes neurologic disorders in children. Next, we investigated the ability of NGS to detect viral sequences in 18 pediatric patients with acute encephalitis/encephalopathy of unknown etiology. DNA and RNA sequencing libraries were prepared using a Nextera XT and ScriptSeq v2, respectively. Indexed samples were pooled and sequenced on MiSeq with 2×75 bp or HiSeq 2500 with the 2×150 bp pair-end protocol to obtain an average of 8,674,293 reads.
Results: The sensitivity of NGS for detection of HHV-6 sequences was equivalent to that of real-time PCR, and the number of HHV-6 reads was significantly correlated with HHV-6 load. In patients with acute encephalitis/encephalopathy, substantial reads of Coxsackievirus A9 and mumps viral sequences were detected in the cerebrospinal fluid of 2 and 1 patients, respectively. Additionally, Torque teno virus and Pepper mild mottle viral sequences were detected in the sera of one patient each.
Conclusion: These data indicate that NGS may be useful for detection of causative viruses in patients with pediatric encephalitis/encephalopathy.
Y. Torii, None
K. Horiba, None
T. Suzuki, None
S. Ando, None
Y. Kamiya, None
Y. Ito, None