Researchers from the Chinese Academy of Sciences claim the pandemic actually originated in India, explaining that a heatwave there from May to June 2019 spawned a water crisis, which in turn led to increased close contact between humans and wild animals such as monkeys.
In a preprint paper with the Lancet medical journal – meaning it has yet to be formally peer reviewed – the Chinese researchers outline their explanation of the “zoonotic transmission” of the SARS-CoV-2 virus from monkeys to humans as they shared water resources.
The researchers also say that India’s poor hygiene conditions and “less efficient” public medical system, as well as its “tropical climate” and “very young population”, were all contributing factors in the virus’s spread.
They estimate that the first “human-to-human transmission” of COVID-19 in India was in July or August.
Back in March, Chinese officials blamed the coronavirus outbreak on US soldiers visiting Wuhan, while last week China pointed the finger at Italy after a study from Milan suggested the virus had been circulating locally since last year.
The identification of India as the possible source of the virus comes after New Delhi last week fortified its military capabilities in Eastern Ladakh, the region by the Chinese border, by building camps for tens of thousands of soldiers. In June, 20 Indian soldiers and an undisclosed number of Chinese were killed as the two sides engaged in a skirmish in the contested border area.
The fresh accusations that coronavirus was first spread in India won’t help relations, and on Friday the Chinese Foreign Ministry appeared to back the claims.
“Although China was the first to report cases, it doesn’t necessarily mean that the virus originated in China,” spokesperson Zhao Lijian said during his regular press conference, in response to a question about the claims against India.
The researchers’ findings have been panned by some western academics, including Professor David Robertson from Glasgow University, who described their approach as “inherently biased.”
“The authors have also ignored the extensive epidemiological data available that shows clear emergence in China and that the virus spread from there,” he told the Daily Mail, “This paper adds nothing to our understanding of SARS-CoV-2.”
The World Health Organization (WHO) has tipped the “Huanan Wholesale Seafood Market in Wuhan City” as the likely source of the novel coronavirus, though the UN special agency is still investigating the pandemic’s origins.
Quotes quotes from the work of Chinese researchers
Methods: In this study, we developed a method to search the least mutated strain using SARS-CoV-2 whole genome sequences. By parsimony principle, the least mutated strain should be the phylogenetic root for all SARS-CoV-2s. We further investigated the SARS-CoV-2’s adaptive evolutionary process in human hosts using the least mutated strain as the phylogenetic root and analyzed its strain diversity in different countries/regions.
Findings: According to their coding region identity, we classified 4571 SARS-CoV-2 genome sequences into 2449 viral strains collected from human hosts between December 2019 and July 2020. We found that the SARS-CoV-2 (NC_045512) strain first identified in Wuhan is not the least mutated strain. There are 41 SARS-CoV-2 strains harboring fewer global point mutations than the NC_045512 strain in our dataset. The least mutated strain can be found in eight countries across four continents due to SARS-CoV-2’s low mutability. Eight positive selection sites are identified in five SARS-CoV-2’s genes and four of them were present in the early stage of SARS-CoV-2’s human-to-human transmission. The NC_045512 strain has two positive selection sites, one in RNA-dependent RNA polymerase (L314P) and the other in spike protein (G614D). The statistical analysis of the SARS-CoV-2’s strain diversity in different countries/regions shows that the Indian subcontinent has the highest strain diversity. Furthermore, based on the SARS-CoV-2’s mutation rate, we estimate that the earliest SARS-CoV-2 transmission in human hosts could be traced back to July or August of 2019.
Interpretation: Our result shows that Wuhan is not the place where human-to-human SARS-CoV-2 transmission first happened. Before it spread to Wuhan, SARS-CoV-2 has already experienced adaptive evolution during its human-to-human transmission. The positive selection sites could contribute to the different clinical features of different SARS-CoV-2 strains. Both the least mutated strain’s geographic information and the strain diversity suggest that the Indian subcontinent might be the place where the earliest human-to-human SARS-CoV-2 transmission occurred, which was three or four months prior to the Wuhan outbreak. Our study helps to elucidate the early cryptic transmission and evolution of SARS-CoV-2 in human hosts and provide the new thinking for the global management of the COVID-19 pandemic.