Lying in wait: the resurgence of dengue virus after the Zika epidemic in Brazil

After the Zika virus (ZIKV) epidemic in the Americas in 2016, both Zika and dengue incidence declined to record lows in many countries in 2017–2018, but in 2019 dengue resurged in Brazil, causing ~2.1 million cases. In this study we use epidemiological, climatological and genomic data to investigate dengue dynamics in recent years in Brazil. First, we estimate dengue virus force of infection (FOI) and model mosquito-borne transmission suitability since the early 2000s. Our estimates reveal that DENV transmission was low in 2017–2018, despite conditions being suitable for viral spread. Our study also shows a marked decline in dengue susceptibility between 2002 and 2019, which could explain the synchronous decline of dengue in the country, partially as a result of protective immunity from prior ZIKV and/or DENV infections. Furthermore, we performed phylogeographic analyses using 69 newly sequenced genomes of dengue virus serotype 1 and 2 from Brazil, and found that the outbreaks in 2018–2019 were caused by local DENV lineages that persisted for 5–10 years, circulating cryptically before and after the Zika epidemic. We hypothesize that DENV lineages may circulate at low transmission levels for many years, until local conditions are suitable for higher transmission, when they cause major outbreaks.

Detection of dengue virus serotype 1 in central nervous system of a child in Bandung, West Java: A case report

Central nervous system involvement of dengue virus is increasingly reported from endemic areas. This study describes the clinical characteristics and laboratory features of a pediatric patient enrolled in a central nervous system illness study conducted in 2017–2018 to identify viral and bacterial etiologies in Indonesian children. Dengue diagnostics including molecular and serological testing were performed on an encephalitis patient who presented with both classical dengue and neurological clinical symptoms. Dengue virus serotype 1 RNA was detected in both cerebrospinal fluid and serum by serotype-specific reverse transcription polymerase chain reaction, and the E gene was successfully sequenced. Anti-dengue virus immunoglobulin M was detected in both admission and discharge sera, whereas anti-dengue virus immunoglobulin G was identified only in the discharge serum. This study describes the central nervous system complications in a case with dengue virus infection in West Java, Indonesia, and highlights the potential for dengue virus serotype 1, a serotype rarely associated with neurotropism, to cause encephalitis.

Frequency of Dengue Virus Serotype 1 in Lahore by In-house assay

Dengue is an important systemic viral infection that is caused by the dengue virus. Ribonucleic acid (RNA) from dengue NS1 positive samples, collected randomly during dengue epidemic from October 2016 to October 2017 at Chugtai Lab, was extracted for nucleic acid. Both the detection and serotyping of dengue samples were performed using real-time PCR on Rotor Gene Q. From the 70 NS1 positive samples, 57 (81.4%) samples were confirmed to be positive for dengue virus RNA, while the remaining 13 (18.6%) were negative. Serotype 1 (DEN-1) were verified among all samples by in-house assay and using commercial kit FTD (Fast Track Diagnostics) dengue differentiation; it was concluded that our in-house assay is in 100% concordance with commercial kit. Serotype 2 (DEN-2) and serotype 3 (DEN-3) have been documented in Pakistan since 1994. Continuous...

Molecular characterization of the viral structural protein genes of 2018 dengue virus serotype 1 epidemic in Yunnan, Southwest China

Background There was a dengue virus serotype 1 (DENV-1) epidemic from October to December in 2018 in Xishuangbanna, Yunnan, southwest China, neighboring Myanmar, Laos and Vietnam. And the molecular characterization, evolution and potential source of DENV from Xishuangbanna were investigate. Methods C (capsid)/prM(premembrane)/E (envelope) genes of DNEV isolated from 87 serum samples obtained from local patients were amplified and sequenced, then evaluated using mutation, phylogenetic and homologous recombination analyses and secondary structure prediction. Results Phylogenetic analysis show that all the DENV strains from Xishuangbanna can grouped in two branch of DENV-1. Out of 52, 50 of isolates were grouped in branch one, and were most similar to Fujian (DQ193572) and Singapore 2016(MF314188) strains. The other two isolates have the closest relationship to Myanmar 2017 (MG679801) . When compared with DENV-1SS (standard strain), we found the amino acid residue of E155 was mutation from T to S,which may related to the virulence of virus and no obvious homologous recombination signals. Secondary structure prediction showed that some changes were found in the helical of MN123849 and MN123854 strains and few changes observed in disordered region. Conclusions This study revealed the molecular characterization of structural genes of xishuangbanna, 2018 epidemic strain, providing a reference for molecular epidemiology, infection, pathogenicity and vaccine development .

Complete Genome Sequence Analysis of an Imported Dengue Virus Serotype 1 Strain from Myanmar

It has been determined that recent dengue virus epidemics in Yunnan, China, originated from Southeast Asian strains. Here, we report the first complete genome sequence and molecular characterization of the imported dengue virus serotype 1 strain YNPE1.