Fast surveillance response reveals the introduction of a new yellow fever virus sub-lineage in 2021, in Minas Gerais, Brazil

BACKGROUND In Brazil, the yellow fever virus (YFV) is maintained in a sylvatic cycle involving wild mosquitoes and non-human primates (NHPs). The virus is endemic to the Amazon region; however, waves of epidemic expansion reaching other Brazilian states sporadically occur, eventually causing spillovers to humans. OBJECTIVES To report a surveillance effort that led to the first confirmation of YFV in NHPs in the state of Minas Gerais (MG), Southeast region, in 2021. METHODS A surveillance network was created, encompassing the technology of smartphone applications and coordinated actions of several research institutions and health services to monitor and investigate NHP epizootics. FINDINGS When alerts were spread through the network, samples from NHPs were collected and YFV infection confirmed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and genome sequencing at an interval of only 10 days. Near-complete genomes were generated using the Nanopore MinION sequencer. Phylogenetic analysis indicated that viral genomes were related to the South American genotype I, clustering with a genome detected in the Amazon region (state of Pará) in 2017, named YFVPA/MG sub-lineage. Fast YFV confirmation potentialised vaccination campaigns. MAIN CONCLUSIONS A new YFV introduction was detected in MG 6 years after the beginning of the major outbreak reported in the state (2015-2018). The YFV strain was not related to the sub-lineages previously reported in MG. No human cases have been reported, suggesting the importance of coordinated surveillance of NHPs using available technologies and supporting laboratories to ensure a quick response and implementation of contingency measures to avoid YFV spillover to humans.

Application of nanopore sequencing technology in viral genome research / 中华实验和临床病毒学杂志

MinION is a commercial nanopore sequencer developed by Oxford Nanopore Techno-logies. Compared with the second-generation sequencing platform, MinION is characterized by ultra-long reads, simple and fast sequencing, high portability and real-time data analysis. MinION has been widely applied to the fields of virus identification, whole genome sequencing, new virus discovery, quasispecies and virus evolution. In this article, we review the application of nanopore sequencing technology in the research of the viral genome in recent years, and discuss the existing problems. We also present the prospect for the development trend of nanopore sequencing in the future.

Rapid and Accurate Sequencing of Enterovirus Genomes Using MinION Nanopore Sequencer / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Knowledge of an enterovirus genome sequence is very important in epidemiological investigation to identify transmission patterns and ascertain the extent of an outbreak. The MinION sequencer is increasingly used to sequence various viral pathogens in many clinical situations because of its long reads, portability, real-time accessibility of sequenced data, and very low initial costs. However, information is lacking on MinION sequencing of enterovirus genomes.</p><p><b>METHODS</b>In this proof-of-concept study using Enterovirus 71 (EV71) and Coxsackievirus A16 (CA16) strains as examples, we established an amplicon-based whole genome sequencing method using MinION. We explored the accuracy, minimum sequencing time, discrimination and high-throughput sequencing ability of MinION, and compared its performance with Sanger sequencing.</p><p><b>RESULTS</b>Within the first minute (min) of sequencing, the accuracy of MinION was 98.5% for the single EV71 strain and 94.12%-97.33% for 10 genetically-related CA16 strains. In as little as 14 min, 99% identity was reached for the single EV71 strain, and in 17 min (on average), 99% identity was achieved for 10 CA16 strains in a single run.</p><p><b>CONCLUSION</b>MinION is suitable for whole genome sequencing of enteroviruses with sufficient accuracy and fine discrimination and has the potential as a fast, reliable and convenient method for routine use.</p>

MinION(TM): New, Long Read, Portable Nucleic Acid Sequencing Device

The MinION(TM) is a miniature nanopore-based analysis device in which the characteristics of an analyte, as it passes through the nanopore, cause changes in the flow of ions through the pore, which are measured, as current flow, by a low noise amplifier and analogue-to-digital converter. Potentially any molecular analyte capable of passing through the nanopore may modify the flow of ions and generate a signal which might be diagnostic. In practice the current device is focussed on DNA sequencing, directly sequencing RNA is a likely development. With the MinION Access Program making the MinION(TM) widely available a flood of applications exploiting its real time, long read capabilities have been published. We review the background to the technology and compare it to current next generation sequencing.