COVID-19 News: Could The SARS-CoV-2 Coronavirus Have Originated From Southern Thailand? Could Southern Thailand Be A Hub Of Coronaviruses?

COVID-19 News: A new research by scientists from the Thai Red Cross Emerging Infectious Diseases Health Science Centre,  Chulalongkorn University-Thailand, King Chulalongkorn Memorial Hospital-Thailand, Duke-NUS Medical School-Singapore, Yangzhou University-China,  Kasetsart University-Thailand, CSIRO Australian Animal Health Laboratory and the Biological Threat Reduction Program, Defense Threat Reduction Agency-USA have found that SARS-CoV-2 related coronaviruses are present in bats and various other animals including pangolins in the Southern parts of Thailand and also in other South-East Asian regions and could have been present for a while now.


 
According to the study abstract there are many questions unanswered for the COVID-19 pandemic are the origin of SARS-CoV-2 and the potential role of intermediate animal host(s) in the early animal-to-human transmission. The discovery of RaTG13 bat coronavirus in China suggested a high probability of a bat origin. Here the study team report molecular and serological evidence of SARS-CoV-2 related coronaviruses (SC2r-CoVs) actively circulating in bats in Southeast Asia. Whole genome sequences were obtained from five independent bats (Rhinolophus acuminatus) in a Thai cave yielding a single isolate (named RacCS203) which is most related to the RmYN02 isolate found in Rhinolophus malayanus in Yunnan, China. SARS-CoV-2 neutralizing antibodies were also detected in bats of the same colony and in a pangolin at a wildlife checkpoint in Southern Thailand. Antisera raised against the receptor binding domain (RBD) of RmYN02 were able to cross-neutralize SARS-CoV-2 despite the fact that the RBD of RacCS203 or RmYN02 failed to bind ACE2. Although the origin of the virus remains unresolved, the study extended the geographic distribution of genetically diverse SC2r-CoVs from Japan and China to Thailand over a 4800-km range. Cross-border surveillance is urgently needed to find the immediate progenitor virus of SARS-CoV-2.
 
The study findings were published in the peer reviewed journal: Nature Communications. https://www.nature.com/articles/s41467-021-21240-1
 
The study stopped short of any implications that the SARS-Cov-2 coronavirus could have originated from Southern Thailand. However it is interesting to note that prior to the COVID-19 pandemic, the traffic flow of Chinese individuals and even Thais travelling between both countries was extremely huge…running into tens of millions every month and so was the trade between both countries. Furthermore it is interesting to note the COVID-19 disease never had a big impact in Thailand compare to other countries as most locals were either asymptomatic or merely experienced very mild symptoms, maybe due to past immunity from numerous circulating coronaviruses. Perhaps the Southern Thailand regions could have been the ‘Hub Of Coronaviruses’ without anyone even knowing! (Thailand has an obsession with the word Hub…always only trying to be the Hub of everything!)
 
The World Health Organization (WHO) meanwhile is on its mission to Wuhan investigating the origin and early transmission of SARS-CoV-2 but this news study shows that SARS-CoV-2-related coronaviruses (SC2r-CoVs) are circulating in animals as far away as Thailand and for a while now.
 
The research findings reports that high levels of neutralizing antibodies against the SARS-CoV-2 virus were present in both bats and pangolins found in the Southern regions of Thailand.
 
The findings further indicate that more SC2r-CoVs are likely to be discovered in the region. Southeast Asia with its large and diverse bat populations may be a more likely hotspot for such viruses.
 
Dr Supaporn Wacharapluesadee, from Thai Red Cross Emerging Infectious Diseases Health Science Centre, Faculty of Medicine, Chulalongkorn University, Bangkok Thailand told media, "This is an important discovery in the search for the origin of SARS-CoV-2, which was made possible by rapid application of cutting-edge technology through transparent international collaboration."
 
The study team examined Rhinolophus bats in a Thai cave. SARS-CoV-2 neutralizing antibodies were detected in bats of the same colony and in a pangolin at a wildlife checkpoint in Southern Thailand.
 
Dr Chee Wah Tan, Senior Research Fellow with Duke-NUS' Emerging Infectious Diseases (EID) program and co-author of this study added, "Our study extended the geographic distribution of genetically diverse SARS-CoV-2-related coronaviruses from Japan and China to Thailand over a 4,800-km range. Cross-border surveillance is urgently needed to find the immediate progenitor virus of SARS-CoV-2.”
 
The study team conducted serological investigations using the SARS-CoV-2 surrogate virus neutralization test (sVNT) developed at Duke-NUS in early 2020.
 
Professor Dr Wang Linfa from Duke-NUS' EID program and corresponding author of this study further added, "Our study demonstrates that our SARS-CoV-2 surrogate virus neutralization test, developed mainly for determining neutralizing antibodies in humans to monitor vaccine efficacy and detect past infections, can also be critical for tracing the animal origin and animal-human spillover events.”
 
Dr Wang's team invented the sVNT assay, trade named cPass, which has been granted Emergency Use Authorization by the US FDA to determine SARS-CoV-2-neutralising antibodies in human sera, due to its good performance concordance with live virus-based assays.
 
Dr Patrick Casey, Professor, Senior Vice Dean for Research, Duke-NUS Medical School concluded, “Studies like this are crucial in furthering our understanding of the many SARS-CoV-2-related viruses that exist in the wild. This work is also timely as investigations into the origins of SARS-CoV-2 are ongoing and may provide further leads on the origin of this outbreak. Such studies also play a key role in helping us be better prepared against future pandemics as they provide a more detailed map of zoonotic threats."
 
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