Recent advances in electron microscopy and tomography have revealed distinct virus-induced endoplasmic reticulum (ER) structures unique for dengue virus (DV) and other flaviviruses in cell culture models, including hepatocytes. These altered ultrastructures serve as sites for viral replication. In this study, we used transmission electron microscopy to investigate whether such structures were present in the liver of fatal dengue hemorrhagic fever (DHF) autopsy cases. In parallel, electron microscopic examination of suckling mouse brains experimentally infected with DV was performed as an in vivo model of acute DV infection. Typical features of ER changes containing abundance of replicative virions were observed in neurons and microglia of DV-infected suckling mouse brains (SMB). This indicated that the in vivo DV infection could induce similar viral replication structures as previously described in the in vitro DV-infected cell model. Nevertheless, liver tissues from autopsy of patients who died of DHF showed scant changes of ER membrane structures and rare particles of virions in hepatocytes, despite overwhelming evidence for the presence of viral antigens and RNA–indicating active virus replication. Instead hepatocytes contained an abundance of steatotic vesicles and structural damages. This lack of structural changes indicative of virus replication in human hepatocytes is discussed.

Here, we present the genome sequences of dengue viruses (DENV) isolated from adult patients in Thailand during 2016–2017: DENV2 (412749), DENV3 (416384), and DENV4 (416709). These sequences provide valuable genetic and evolutionary information for dengue research and antiviral development.

We sequenced the genome of dengue virus serotype 1 (DENV1) strain 4101301, isolated from a child with dengue fever in Thailand and cultured in C6/36 mosquito cells. These data are crucial for studying DENV1’s genetic diversity, evolution, and epidemiology and advancing the knowledge for developing antiviral drugs and vaccines targeting DENV.