Background: Wenzhou virus (WENV), a member of the Mammarenavirus genus in the Arenaviridae family, has been detected in wild rodents from eight provinces in China, including Zhejiang, Shandong, Hainan, Xinjiang, Hunan, Guangdong, Yunnan, and Jiangxi provinces, and some countries from Southeast Asia. The IgG-antibodies of WENV have been detected in both healthy populations and patients with unknown fever and respiratory symptoms. However, the potential harmfulness of WENV to humans has been underestimated due to mild symptoms after infection, similar to respiratory diseases. Thus, it is imperative to enhance the surveillance of WENV in wild rodents, particularly Rattus norvegicus, and continuously monitor its prevalence.
Results: From 2017 to 2021, a total of 390 wild rodents were collected from six provinces in the eastern and southern coastal areas, containing nine species of rats. Samples of each tissue were collected, and PCR amplified for identification. Four R. norvegicus samples were detected to be WENV-positive. No genomic sequence of WENV was detected in Rattus flavipectus, Rattus losea, Suncus murinus, Apodemus agrarius, Mus musculus, Microtus fortis, Micromys minutus, and Niviventer niviventer from Jiangsu, Zhejiang, Fujian, Hainan, Guangdong and Guangxi provinces. Three genomic sequences were identified to be WENV by phylogenetic analysis. The full-length sequences of HAIKOU-40 were amplified in R. norvegicus from Hainan, which showed a close relationship to Wufeng/ WFS, sharing 84.5-89.4% homology at the nucleotide level and 91.6-98.9% homology at the amino acid level. Phylogenetic analysis revealed that HAIKOU-40 formed an Asia-specific cluster with all WENVs and Loie River mammarenavirus (LORV), provisionally named Asian ancestry. This cluster has diverged earlier from the remaining mammarenavirus. The sequences obtained in Xiamen, Fujian province showed more than 90% nucleotide identities with WENV, which may be a strain of WENV. Additionally, the sequence of Wuxi-87 which was a positive sequence detected in Wuxi, Jiangsu province exhibited 83% nucleotide identity with Lassa virus (LASV). Further efforts will be made to isolate and identify this virus strain, verify the relationship between Wuxi-87 and LASV, and confirm whether R. norvegicus is a new host of LASV.
Conclusions: In this study, we conducted a systematic examination of the prevalence of WENV among rodents on the southeast coast of China. Additionally, we characterized the genome of a newly discovered WENV strain, that confirmed the role of R. norvegicus in the transmission of WENV. This highlights the importance of investigating the prevalence of WENV in both wild rodents and humans.
Keywords: Epidemiology; Genomic characterization; Rodents; Southeast coastal region; Wenzhou virus.
© 2023. The Author(s).