(Source: DHS Science and Technology, Master Question List for COVID-19 (caused by SARS-CoV-2), Weekly Report, 18 March 2020)

Forensics (Part 11)

Natural vs intentional use? Tests to be used for attribution.

What is known?

• Genomic analysis has put SARS-CoV-2 into the beta-coronavirus clade, with close relationship to bat viruses. The SARS-CoV-2 virus is different from SARS and MERS viruses.¹
• According to genomic analysis, SARS-CoV-2 is a natural variant, and is unlikely to be human-derived or otherwise created by “recombination” with other circulating strains of coronavirus.^2,3  
• Some genomic evidence points to a close relationship with pangolin coronaviruses. Data indicate that pangolins may be a natural host for beta-coronaviruses.^4,5 Additional research is required.
• Genomic data support at least two possible origins of SARS-CoV-2: “(i) natural selection in a non-human animal host before zoonotic transfer, and (ii) natural selection in humans following zoonotic transfer.”² Either scenario is consistent with the observed genetic changes found in all known SARS-CoV-2 isolates.
• SARS-CoV-2 is not derived from any previously used virus backbone, reducing the likelihood of laboratory origin,² and genomic evidence does not support the idea that SARS-CoV-2 is a laboratory construct; however, it is currently not possible to prove or disprove the other theories of its origin. ²  

What do we need to know?

• What tests for attribution exist for coronavirus emergence?
• What is the identity of the intermediate species?
• Are there closely related circulating coronaviruses in bats or other animals with the novel PRRA cleavage site found in SARS-CoV-2?

References

1. Dong, N.; Yang, X.; Ye, L.; Chen, K.; Chan, E. W.-C.; Yang, M.; Chen, S., Genomic and protein structure modelling analysis depicts the origin and infectivity of 2019-nCoV, a new coronavirus which caused a pneumonia outbreak in Wuhan, China. bioRxiv 2020, 2020.01.20.913368.
2. Andersen, K. G.; Rambaut, A.; Lipkin, W. I.; Holmes, E. C.; Garry, R. F., The proximal origin of SARS-CoV-2. Nature Medicine 2020.
3. Zhou, P.; Yang, X.-L.; Wang, X.-G.; Hu, B.; Zhang, L.; Zhang, W.; Si, H.-R.; Zhu, Y.; Li, B.; Huang, C.-L.; Chen, H.-D.; Chen, J.; Luo, Y.; Guo, H.; Jiang, R.-D.; Liu, M.-Q.; Chen, Y.; Shen, X.-R.; Wang, X.; Zheng, X.-S.; Zhao, K.; Chen, Q.-J.; Deng, F.; Liu, L.-L.; Yan, B.; Zhan, F.-X.; Wang, Y.-Y.; Xiao, G.; Shi, Z.-L., Discovery of a novel coronavirus associated with the recent pneumonia outbreak in humans and its potential bat origin. bioRxiv 2020, 2020.01.22.914952.
4. Liu, P.; Chen, W.; Chen, J.-P., Viral Metagenomics Revealed Sendai Virus and Coronavirus Infection of Malayan Pangolins (Manis javanica). Viruses 2019, 11 (11), 979.
5. Liu, P.; Jiang, J.-Z.; Wan, X.-F.; Hua, Y.; Wang, X.; Hou, F.; Chen, J.; Zou, J.; Chen, J., Are pangolins the intermediate host of the 2019 novel coronavirus (2019-nCoV) ? bioRxiv 2020, 2020.02.18.954628.

Dr KK Aggarwal

President CMAAO