Favipiravir is an oral broad-spectrum inhibitor of viral RNA-dependent RNA polymerase that is approved for treatment of influenza in Japan. We conducted a prospective, randomized, open-label, multicenter trial of favipiravir for the treatment of COVID-19 at 25 hospitals across Japan. Eligible patients were adolescents and adults admitted with COVID-19 who were asymptomatic or mildly ill and had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. Patients were randomly assigned at a 1:1 ratio to early or late favipiravir therapy (in the latter case, the same regimen starting on day 6 instead of day 1).

Sixty-two new Japanese encephalitis virus (JEV) isolates were obtained from mosquitoes, biting midges, human cerebrospinal fluid and human blood samples in China during 2002–2005. The E and prM genes were sequenced and phylogenetic analyses were performed with 38 JEV other isolates from China and 36 JEV strains from other countries. Phylogenetic trees based on the E and prM gene sequences were similar. The results indicate that: (i) recent JEV isolates from China are divided into two genotypes, genotype 1 and genotype 3; (ii) recent JEV isolates from China are grouped into the same clusters within genotypes 1 and 3; and (iii) genotype 1 JEV strains have been isolated in China since 1979, whilst genotype 3 JEV strains were isolated before the 1970s. The results suggest that genotype 1 JEV was introduced to China around 1979 and that JEV strains belonging to genotypes 1 and 3 circulate in China.

The fluorogenic TaqMan reverse transcriptase PCR (RT-PCR) assay was developed for detecting each of the dengue virus (DV) types 1 to 4. DV genome was detected in all the 35 serum samples from confirmed dengue cases by the TaqMan RT-PCR, although it was not detected in 13 and 21% by conventional type-specific and cross-reactive RT-PCR, respectively.

The reemergence of dengue virus (DENV) infection has created a requirement for improved laboratory diagnostic procedures. In this study, DENV genome detection in urine was evaluated as a diagnostic method. The DENV genome was detected by real-time reverse transcriptase PCR (RT-PCR) in urine and serum of dengue patients. The detection rate of DENV genome in urine was 25% (2/8) on disease days 0 to 3 and 32% (7/22) on days 4 to 5. The rate was 50% or higher on days 6 to 16, 52% (11/21) on days 6 to 7, 78% (7/9) on days 8 to 9, 80% (4/5) on days 10 to 11, 50% (2/4) on days 12 to 13, and 60% (3/5) on days 14 to 16. The last positive urine sample was on day 16. The detection rates in serum were highest on days 0 to 3 and were greater than 50% on days 0 to 7. Detection rates decreased thereafter, and the last positive detection was on day 11. These results indicate that the time frames for positive detection differ between urine and serum samples, whereby detection rates of 50% or higher are evident between days 6 to 16 for urine samples and days 0 to 7 for serum samples. Nucleotide sequences of PCR products were identical between urine and serum samples. The detection of DENV genome in urine samples by real-time RT-PCR is useful to confirm DENV infection, particularly after viremia disappears.

Dengue virus (DENV) infectious disease is a major public health problem worldwide; however, licensed vaccines or specific antiviral drugs against this infection are not available. To identify novel anti-DENV compounds, we screened 1280 pharmacologically active compounds using focus reduction assay. Bromocriptine (BRC) was found to have potent anti-DENV activity and low cytotoxicity (half maximal effective concentration [EC50], 0.8-1.6 μM; and half maximal cytotoxicity concentration [CC50], 53.6 μM). Time-of-drug-addition and time-of-drug-elimination assays suggested that BRC inhibits translation and/or replication steps in the DENV life cycle. A subgenomic replicon system was used to verify that BRC restricts RNA replication step. Furthermore, a single amino acid substitution (N374H) was detected in the NS3 protein that conferred resistance to BRC. In summary, BRC was found to be a novel DENV inhibitor and a potential candidate for the treatment of DENV infectious disease.