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Hemorrhagic fever with renal syndrome (HFRS) is caused by hantavirus (HV) infection, and is prevalent across Europe and Asia (mainly China). The genetic variation and wide host range of the HV family may lead to vaccine failure. In this study, we analyzed the gene sequences of HV isolated from different regions of China in order to trace the molecular evolution of HV and the epidemiological trends of HFRS. A total of 16,6975 HFRS cases and 1,689 HFRS-related deaths were reported from 2004 to 2016, with the average annual incidence rate of 0.9674 per 100,000, 0.0098 per 100,000 mortality rate, and case fatality rate 0.99%. The highest number of cases were detected in 2004 (25,041), and after decreasing to the lowest numbers (8,745) in 2009, showed an incline from 2010. The incidence of HFRS is the highest in spring and winter, and three times as many men are affected as women. In addition, farmers account for the largest proportion of all cases. The main hosts of HV are Rattus norvegicus and Apodemus agrarius, and the SEOV strain is mainly found in R. norvegicus and Niviventer confucianus. Phylogenetic analysis showed that at least 10 HTNV subtypes and 6 SEOV subtypes are endemic to China. We found that the clustering pattern of M genome segments was different from that of the S segments, indicating the possibility of gene recombination across HV strains. The recent increase in the incidence of HFRS may be related to climatic factors, such as temperature, relative humidity and hours of sunshine, as well as biological factors like rodent density, virus load in rodents and genetic variation. The scope of vaccine application should be continuously expanded, and surveillance measures and prevention and control strategies should be improved to reduce HFRS infection in China.

An electrochemical biosensor was prepared for nucleic acid-based hantavirus detection using a Cu-based metal-organic framework (CuMOF) as a signal tag. The CuMOF was synthesized by the solvothermal method and then covalently bonded with signal DNA (sDNA) probes. The Au nanoparticles and reduced graphene oxide composite were deposited on the electrode surface by electroreduction as support substrate and was then functionalized with capture DNA (cDNA) probes by self-assembly. Through the complementary base pairing, the target DNA (tDNA) fragment of hantavirus hybridized with the cDNA and the sDNA in a sandwich-type format. The tDNA was detected according to the current signal of the CuMOF catalyzed reaction using o-phenylenediamine as redox substrate. The peak current of the biosensor at − 0.55 V increased linearly in proportion to the logarithmic value of the tDNA concentration from 10−15 to 10−9 mol/L, with a detection limit of 0.74 × 10−15 mol/L. Moreover, the proposed biosensor was successfully applied to detect hantavirus and was able to distinguish hantavirus from other arboviruses.

Background: By the end of August 2020, >23 million cases and 800,000 deaths were attributed to SARS-CoV-2 in >200 countries. The improvement of simple, rapid, and efficient detection methods is of great significance for the early detection, timely isolation, and protection of susceptible populations. This study aimed to provide an alternative method for the rapid detection of viral nucleic acid.Methods: This study provided a rapid nucleic acid detection method mediated by recombinant enzyme based on the novel coronavirus (SARS-CoV-2). Primers and probes were designed based on the N gene sequence of coronavirus. The method was performed at 39 °C, the detection time was short (1 copies/mL.Results: The primer-probe did not show any cross-reaction with adenovirus, Zika virus, influenza B virus, and chikungunya virus, with good specificity. A total of 106 clinical throat swab samples were compared by reverse transcription recombinase-aided amplification (RT-RAA) and commercial reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR); the results were identical.Conclusions: The novel coronavirus RT-RAA method established in this study had high sensitivity, strong specificity, simple operation, and fast detection speed, and hence, is suitable for the rapid detection of novel coronavirus under the current epidemic situation.

Dabieshan tick virus (DBV) belongs to Phlebovirus and its pathogenicity to human and animals is unknown. To investigate the presence of Dabieshan tick virus in Zhoushan, 353 ticks were collected from May 2018 to October 2019. The detection result showed that the average prevalence rate among these samples was 30.3% (107 positives out of 353 samples), which means DBVs are widely distributed in tick populations in Zhoushan of China. In a phylogenetic analysis based on the nucleotide sequences of the L and S segments of the virus (ZS-DBS-2018 tick virus) in the study, it clustered with Dabieshan tick virus (KM817666.1, KM817733.1) with a 97.1% and 99.6% nucleotide identity, respectively. Further studies involving virus isolation are required to characterize Dabieshan tick virus and to expand the geographical distribution of the sampled ticks.

Background As of 2 March, 2020, at least 80 151 coronavirus disease 2019 (COVID-19) cases were reported in China. Most of the patients had a history of visiting Hubei Province or contacting with people who had ever stayed in or passed by Hubei Province or were exposed to symptoms. Some patients got infected through only asymptomatic contact. This study aimed to report the epidemic features and lab identification of a patient confirmed with COVID-19 infection through only asymptomatic contact. Case presentation A 44-year-old man, who lived in Nanchang, Jiangxi Province, China until 6 March 2020, suffered from cough on 27 January 2020. Fever symptoms appeared on 28 January, with a maximum temperature of 38.8 °C, accompanied by cough, sore throat, headache, fatigue, muscle ache, joint ache, and other symptoms. The symptoms continued until he was hospitalized on 30 January. Coronavirus conventional polymerase chain reaction assay was positive for the throat swab sample. The patient, along with his wife and son, drove from Nanchang to back to Honghu City, Hubei Province, on 23 January 2020. After staying with his parents and brother’s family for 3 days, the patient drove back to Nanchang and arrived on 25 January. On the way back home, they stopped by Tongshan service area, Hubei Province, without any close contact with other people. After arriving home in Nanchang City, Jiangxi Province, none of them left their residence. In addition, his parents stayed at home for 20 days with his younger brother’s family before they got back. His younger brother and one of his brother’s children visited Wuhan on 5 January and came home on 6 January 2020. Conclusions This report suggested that, in the early phase of COVID-19 pneumonia, routine screening could miss patients who were virus carriers. Highlighting travel history is of paramount importance for the early detection and isolation of severe acute respiratory syndrome coronavirus 2 cases.

Background Anopheles sinensis is one of the major malaria vectors in China and other southeast Asian countries, including Vietnam, Cambodia, Thailand. Vector control is considered to be the critical measure for malaria control, while the increasing prevalence of insecticide resistance caused by long-term use of insecticides, especially pyrethroids, is threatening the successful control of An. sinensis. In order to understand the underlying resistance mechanisms involved and molecular basis, the principal malaria vector, An. sinensis from Jiangsu and Anhui provinces, Southeast China, was investigated. Methods The adult Anopheles mosquitoes were sampled from multiple sites across Jiangsu and Anhui provinces, and sufficient mosquitoes collected from eleven sites for insecticide susceptibility bioassays. The DIIS4–DIIS6 region of the para-type sodium channel gene was amplified and sequenced, then multiple PCR and Taqman assays were used to assess the frequencies of kdr mutations at the target gene. Results In the present study, most of the adult An. sinensis populations were pyrethroids resistant, which indicated the presence of kdr resistance mutations in the para-type sodium channel gene. Sequence analyses demonstrated the kdr mutation existed at codon 1014 in Jiangsu and Anhui provinces. In adult An. sinensis, three mutant types (TTT L1014F, TTC L1014F, and TGT L1014C) of kdr alleles were detected, while no wild type (TTG L1014) was observed. The TTC L1014F mutation was first reported in Anhui province. Conclusions The highly polymorphic kdr alleles were observed in all the adult An. sinensis populations, which suggested that in-depth studies are required for carrying on insecticide resistance monitoring and specific resistance mechanisms studying into establish effective long-term malaria vector control program in eastern China.

SARS coronavirus (SARS-CoV), the causative agent of the large SARS outbreak in 2003, originated in bats. Many SARS-like coronaviruses (SL-CoVs) have been detected in bats, particularly those that reside in China, Europe, and Africa. To further understand the evolutionary relationship between SARS-CoV and its reservoirs, 334 bats were collected from Zhoushan city, Zhejiang province, China, between 2015 and 2017. PCR amplification of the conserved coronaviral protein RdRp detected coronaviruses in 26.65% of bats belonging to this region, and this number was influenced by seasonal changes. Full genomic analyses of the two new SL-CoVs from Zhoushan (ZXC21 and ZC45) showed that their genomes were 29,732 nucleotides (nt) and 29,802 nt in length, respectively, with 13 open reading frames (ORFs). These results revealed 81% shared nucleotide identity with human/civet SARS CoVs, which was more distant than that observed previously for bat SL-CoVs in China. Importantly, using pathogenic tests, we found that the virus can reproduce and cause disease in suckling rats, and further studies showed that the virus-like particles can be observed in the brains of suckling rats by electron microscopy. Thus, this study increased our understanding of the genetic diversity of the SL-CoVs carried by bats and also provided a new perspective to study the possibility of cross-species transmission of SL-CoVs using suckling rats as an animal model.

Bats have been shown as important mammal resevoirs to carry a variety of zoonotic pathogens. To analyze pathogenic species in bats from southeast coastal regions of China, we performed metagenomic sequencing technology for high throughput sequencing of six sentinels from southeast coastal area of China. We obtained 5,990,261 high quality reads from intestine and lung tissue of 235 bats, including 2,975,371 assembled sequences. 631,490 reads predicted overlapping sequences for the open reading frame (ORF), which accounts for 2.37% of all the sequences (15,012/631,490). Further, the acquired virus sequences were classified into 25 viral families, including 16 vertebrate viruses, four plant viruses and five insect viruses. All bat samples were screened by specific PCR and phylogenetic analysis. Using these techniques, we discovered many novel bat viruses and some bat viruses closely-related to known human/animal pathogens, including coronavirus, norovirus, adenovirus, bocavirus, astrovirus, and circovirus. In summary, this study extended our understanding of bats as the viral reservoirs. Additionally, it also provides a basis for furher studying the transmission of viruses from bats to humans.