Pangolins confiscated from the illegal wildlife trade in Vietnam harboured coronaviruses related to SARS-CoV-2, something previously detected only in China, reports a study in Frontiers in Public Health.
The study offers further evidence that the wildlife trade can add to coronavirus transmission.
“This confirms the presence of coronaviruses in the SARS-CoV family in trafficked pangolins in Vietnam. Eliminating the trade in pangolins and other wild mammals and birds will eliminate this high-risk pathway for viral spillover and pathogen emergence,” said lead author Nguyen Thi Thanh Nga of Vietnam’s Wildlife Conservation Society (WCS).
To conduct the study, researchers at the WCS and elsewhere in Vietnam and the United States tested specimens from 246 pangolins confiscated in Vietnam from 2015 to 2018. Seven of those animals from a group of 15 confiscated tested positive for a SARS-CoV-2–related coronavirus.
From 2016 to 2020, law enforcement officials carried out 91 independent pangolin confiscations in 23 Vietnamese provinces and the cities of Ha Noi and Ho Chi Minh, the authors said. Pangolins have been discussed as possible “bridge species” for the jump of SARS-CoV-2 from animals to humans.
Study details
Evidence of SARS-CoV-2 Related Coronaviruses Circulating in Sunda pangolins (Manis javanica) Confiscated From the Illegal Wildlife Trade in Viet Nam
Nguyen Thi Thanh Nga, Alice Latinne, Hoang Bich Thuy, Nguyen Van Long, Pham Thi Bich Ngoc, Nguyen Thi Lan Anh, Nguyen Van Thai, Tran Quang Phuong, Hoang Van Thai, Lam Kim Hai, Pham Thanh Long, Nguyen Thanh Phuong, Vo Van Hung, Le Tin Vinh Quang, Nguyen Thi Lan, Nguyen Thi Hoa, Christine Johnson, Jonna Mazet, Scott Roberton, Chris Walzer, Sarah Olson and Amanda Fine.
Published in Frontiers in Public Health on 9 March 2022
Despite the discovery of several closely related viruses in bats, the direct evolutionary progenitor of SARS-CoV-2 has not yet been identified. In this study, we investigated potential animal sources of SARS-related coronaviruses using archived specimens from Sunda pangolins (Manis javanica) and Chinese pangolins (Manis pentadactyla) confiscated from the illegal wildlife trade, and from common palm civets (Paradoxurus hermaphroditus) raised on wildlife farms in Viet Nam.
A total of 696 pangolin and civet specimens were screened for the presence of viral RNA from five zoonotic viral families and from Sarbecoviruses using primers specifically designed for pangolin coronaviruses.
We also performed a curated data collection of media reports of wildlife confiscation events involving pangolins in Viet Nam between January 2016 and December 2020, to illustrate the global pangolin supply chain in the context of Viet Nam where the trade confiscated pangolins were sampled for this study. All specimens from pangolins and civets sampled along the wildlife supply chains between February 2017 and July 2018, in Viet Nam and tested with conventional PCR assays designed to detect flavivirus, paramyxovirus, filovirus, coronavirus, and orthomyxovirus RNA were negative.
Civet samples were also negative for Sarbecoviruses, but 12 specimens from seven live pangolins confiscated in Hung Yen province, northern Viet Nam, in 2018 were positive for Sarbecoviruses.
Our phylogenetic trees based on two fragments of the RdRp gene revealed that the Sarbecoviruses identified in these pangolins were closely related to pangolin coronaviruses detected in pangolins confiscated from the illegal wildlife trade in Yunnan and Guangxi provinces, China. Our curated data collection of media reports of wildlife confiscation events involving pangolins in Viet Nam between January 2016 and December 2020, reflected what is known about pangolin trafficking globally.
Pangolins confiscated in Viet Nam were largely in transit, moving toward downstream consumers in China. Confiscations included pangolin scales sourced originally from Africa (and African species of pangolins), or pangolin carcasses and live pangolins native to Southeast Asia (predominately the Sunda pangolin) sourced from neighboring range countries and moving through Viet Nam toward provinces bordering China.
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Coronaviruses closely related to SARS-CoV-2 discovered outside China
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