Antu Virus - A New Pathogenic Orthonairovirus Discovered Near The Borders Of China And North Korea
World Medical News - Antu Virus May 16, 2023 11 months, 3 days, 7 hours, 54 minutes ago
World Medical News: In the unending battle between humans and infectious diseases, the discovery of a new viral species is a monumental moment. In a recent breakthrough, researchers from the Chinese Center for Disease Control and Prevention-Beijing and the Yanbian Korean Autonomous Prefecture Center for Disease Control and Prevention-Jilin, have identified a novel virus now named as the Antu Virus, belonging to the Orthonairovirus genus, from the Dermacentor silvarum tick species. This discovery occurred near the border between North Korea and China.
The Viral Foe: Orthonairoviruses
Orthonairoviruses are no strangers to disease transmission. Viruses from this genus and the broader Nairoviridae family are known for their role in the spread of diseases like the Nairobi sheep disease and Crimean-Congo hemorrhagic fever (CCHF). Additionally, several other poorly characterized viruses belonging to these groups have been isolated from mammals and ticks as covered in previous
World Medical News coverages.
The viral particles of Orthonairoviruses are spherical, with diameters ranging between 80.0 and 120.0 nm, and enveloped by a membranous structure. They carry three segments of single-stranded RNA, with lengths varying between 17.0 and 23.0 kilobases. As vectors of disease, ticks play a significant role in the transmission of these viruses, emphasizing the need for continuous surveillance to identify new viral species. Early detection of these pathogens can facilitate prompt diagnosis and treatment, thereby reducing the global health burden they impose.
The Discovery of Antu Virus
The study unfolded in a forest in Antu, located proximal to the China-North Korea border. On April 17, 2021, researchers collected ticks by dragging corduroy through the forest. The ticks were identified based on their morphological characteristics, homogenized, and their supernatants inoculated onto Vero E6 cells. After three consecutive passages, the team observed cytopathic effects in the cells, suggesting viral infection.
Subsequent transmission electron microscopy (TEM) analysis of the infected cells revealed the presence of enveloped viruses resembling Bunyavirales viruses in morphology. Viral RNA was then extracted, and after a series of processes including cDNA synthesis, DNA library preparation, and Sanger sequencing, the viral reads were filtered and assembled to form contigs.
In total, researchers identified 264 ticks of three different species, with the Dermacentor silvarum tick inoculates, labeled as YB_tick_2021_24, showing cytopathic effects among Vero E6 cells four days post-inoculation. This indicated the presence of a pathogenic virus.
The team generated over 40 million viral reads and related contigs, three of which were identified as belonging to the Songling virus (SLV), a known Orthonairovirus.
Decoding the Antu Virus
Through RACE polymerase chain reaction (PCR), researchers quantified viral reads and determined the genomic lengths for the large, medium, and small segments of the virus. The results were uploaded to the GenBank genetic sequence database, and open reading
frames (ORFs) were identified. The analysis showed the viral strain belonged to the Orthonairovirus genus and the Nairoviridae family of viruses and was genetically similar to SLV.
Interestingly, the nucleotides at the terminal ends of the small segment were similar to those of other orthonairoviruses. However, those of the medium and large contigs differed, suggesting the uniqueness of the newly discovered strain. When compared with the SLV sample, the Antu virus showed varying degrees of similarity in amino acids and nucleic acids across the different segments, ranging from 72% to 85%.
These results indicated the strain was indeed a new species of Orthonairovirus, which was subsequently named the Antu virus.
Conclusions
The study's findings were consequential as they highlighted the isolation of a new Orthonairovirus species from Dermacentor silvarum ticks near the China-North Korea border. Genetic similarities and phylogenetic analysis results indicated that this new virus was genetically similar to the Songling virus. Given that the Songling virus and other Orthonairoviruses are known to infect livestock and humans, the discovery of the Antu virus underscores the importance of increased surveillance in the region.
The discovery of this novel Orthonairovirus could serve as a catalyst for future research into tick-borne diseases, and highlights the critical role of ongoing viral surveillance in safeguarding global health.
The study findings were published in the U.S. CDC’s journal: Emerging Infectious Diseases.
https://wwwnc.cdc.gov/eid/article/29/6/23-0056_article
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