Diversity and independent evolutionary profiling of rodent-borne viruses in Hainan,a tropical island of China

The risk of emerging infectious diseases(EID)is increasing globally.More than 60%of EIDs worldwide are caused by animal-borne pathogens.This study aimed to characterize the virome,analyze the phylogenetic evolution,and determine the diversity of rodent-borne viruses in Hainan Province,China.We collected 682 anal and throat samples from rodents,combined them into 28 pools according to their species and location,and processed them for next-generation sequencing and bioinformatics analysis.The diverse viral contigs closely related to mammals were assigned to 22 viral families.Molecular clues of the important rodent-borne viruses were further identified by polymerase chain reaction for phylogenetic analysis and annotation of genetic characteristics such as arenavirus,coronavirus,astrovirus,pestivirus,parvovirus,and papillomavirus.We identified pestivirus and bocavirus in Leopoldoms edwardsi from Huangjinjiaoling,and bocavirus in Rattus andamanensis from the national nature reserves of Bangxi with low amino acid identity to known pathogens are proposed as the novel species,and their rodent hosts have not been previously reported to carry these viruses.These results expand our knowledge of viral classification and host range and suggest that there are highly diverse,undiscovered viruses that have evolved independently in their unique wildlife hosts in inaccessible areas.

Phylogenetic Analysis of the Dengue Virus Strains Causing the 2019 Dengue Fever Outbreak in Hainan,China

Dengue virus is an arthropod-borne pathogen that is transmitted to humans primarily by Aedes spp.mosquitos,causing the acute infectious disease,dengue fever(DF).Until 2019,no dengue outbreak had been reported in Hainan Province for over 20 years.However,in early September of 2019,an increasing number of infected cases appeared and the DF outbreak lasted for over one month in Haikou City,Hainan Province.In our study,we collected 97 plasma samples from DF patients at three hospitals,as well as 1585 mosquito larvae samples from puddles in different areas of Haikou.There were 49(50.5%)plasma samples found to be strongly positive and 9(9.3%)plasma samples were weakly positive against the NS1 antigen.We discovered DENV both in the patient's plasma samples and mosquito larvae samples,and isolated the virus from C6/36 cells inoculated with the acute phase serum of patients.Phylogenetic analysis revealed that the new strains were the most closely related to the epidemic strain in the southern regions of China,belonging to lineageⅣ,genotypeⅠ,DENV-1.Compared to the seven closest strains from neighboring countries and provinces,a total of 18 amino acid mutations occurred in the coding sequences(CDS)of the new isolated strain,DENV1 HMU-HKU-2.Our data shows that dengue virus is re-emerged in Hainan,and pose new threats for public health.Thus regular molecular epidemiological surveillance is necessary for control and prevention of DENV transmission.