Dengue fever virus (DENV) is a mosquito-borne flavivirus that poses a serious risk to human health. Aedes albopictus is a widely distributed vector of dengue fever in China. Based on the impact of physiological activity, the microbiome in A. albopictus will provide a novel environment-friendly approach to control DENV transmission. We performed metagenomic sequencing on A. albopictus before and after exposure to DENV blood meal to detect microbiome variation of A. albopictus with different susceptibilities to DENV. The dominant phyla in A. albopictus microbiome were Proteobacteria and Ascomycota, and the dominant genera were Aspergillus and Metarhizium. Gammaproteobacteria bacterium, Lactobacillus harbinensis, and Neurospora crassa differed significantly after DENV infection. There were 15 different microorganisms found to be involved in mosquito immunity and metabolism, such as Alphaproteobacteria bacterium, Methyloglobulus morosus, and Shigella sonnei, which might have an impact on the DENV susceptibility of A. albopictus. It was hypothesized that the lack of specific bacteria may lead to increased susceptibility of A. albopictus to DENV. Interventions in the microbiome composition or specific bacteria of A. albopictus may affect the susceptibility to DENV and control the mosquito-borne diseases efficiently.

ObjectiveWild animal pathogen surveillance will help to understand the next possible pandemic in advance. Rodents, which have close contact with humans, are generally regarded as a key factor for zoonotic disease control. Given the variation in rodent virus composition in diverse ecologies, we conducted a study on the viral infection of rodents of diverse species in different typical environments of Heilongjiang and Yunnan Provinces, located in northeastern and southwestern China, respectively.MethodsViral metagenomics sequencing and bioinformatic analysis were performed to determine the different distributions of rodent-borne viruses in typical environments of Heilongjiang and Yunnan Provinces, China. After viral culture and PCR confirmation, genomic and phylogenetic quantitative analysis was performed on the detected hantaviruses (HVs) and Beilong viruses (BeiVs).ResultsNineteen rodents from three species and 35 rodents from five species of rodents were collected from Heilongjiang and Yunnan Provinces, respectively. Although the number and number of species of rodents trapped in the northeast were fewer than those in the southwest, viruses annotated from rodents in Heilongjiang were more diverse than those in Yunnan. Rodents carried 22 virus families in Heilongjiang and 13 families in Yunnan. Sequences assembled from Rattus norvegicus were annotated to the M, L, and S segments of HV, and all were clustered within the Seoul-type hantavirus (SEOV). There were 2 (R81Q, S698T) and 4 (K153R, M168I, I279S, and R1790K) amino acid site substitutions in M and L compared with the versions in the most homologous strains. Two BeiV isolates from Rattus norvegicus were closely related to BeiV from brown rats in Hong Kong, with high bootstrap values of >90% in the N segment and > 95% in the L segment. They were further clustered with Tailam virus, forming a distinct group in Paramyxoviridae.ConclusionThe rodents from Heilongjiang and Yunnan located in northeast and southwest China, respectively, had different viral spectra, and only one-third (10/32) of virus families were detected in both areas. The predominant viruses were HV and BeiV in the Hantaviridae and Paramyxoviridae families, respectively. Rodent-borne viruses in the same species were similar in different geographic disparate areas owing to their similar close contact with human habitats and human activities. Additional attention should be given to the monitoring of neglected rodent-borne viruses, especially opportunistic viruses with currently low loads.

The complete mitogenome sequence of the Eurasian least shrew (Sorex minutissimus) was determined using long PCR. The genome was 17,061 bp in length and contained 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, 1 origin of L strand replication and 1 control region. The overall base composition of the heavy strand is A (32.6%), C (24.7%), T (29.1%) and G (13.6%). The base compositions present clearly the AT skew, which is most obviously in the control region and protein-coding genes. The extended termination-associated sequence domain, the central conserved domain and the conserved sequence block domain are defined in the mitochondrial genome control region of the Eurasian least shrew. Mitochondrial genome analyses based on MP, ML, NJ and Bayesian analyses yielded identical phylogenetic trees. The ten Sorex species formed a monophyletic group with the high bootstrap value (100%) in all examinations.