Pangolins briefly became global media stars at the dawn of the Covid-19 pandemic as the suspected intermediate animal hosts that transmitted SARS-CoV-2 from bats to humans, before later being dismissed in internet mockery when that transmission hypothesis was invalidated.
As theconversation.com reported, that initial 99% claim vanished when the team shared a preprint on bioRxiv about ten days later, revealing the genome similarity was actually around 90%.
- Genomic Similarity: Early claims of a 99% match between pangolin coronaviruses and SARS-CoV-2 were miscommunications regarding a partial gene sequence, not the entire viral genome.
- The Receptor Binding Domain (RBD): Pangolin viruses share a striking resemblance to SARS-CoV-2 in the specific spike protein region that binds to human cells, sparking initial recombination theories.
- The Current Scientific Consensus: Subsequent discoveries of closer bat coronaviruses, such as BANAL-20-52 found in Laos, mean researchers no longer rely on pangolins to explain the evolutionary origin of the viral spike receptor binding domain.
The pangolin coronavirus presented in early 2020 was not actually a newly discovered pathogen. It originated from animals seized by customs officers in Guangdong province in 2019, with raw sequencing data deposited under an embargo on a United States database on September 20, 2019, according to theconversation.com.
When the original 2019 study was published a month later, the data embargo remained active. Following inquiries prompted by the unfolding pandemic, database managers lifted the embargo on January 22, 2020, making the sequences public.
Researcher Matt Wong subsequently posted a note on the Virological platform on January 30, 2020, drawing attention to these public Guangdong sequences. Simultaneously, a Hong Kong team analyzed separate pangolin samples from Guangxi province and submitted their findings to the journal Nature on February 7, 2020.
Following the February 7 press conference, six preprints concerning pangolin coronaviruses appeared on bioRxiv within a single week. The simultaneous release dates stemmed from moderator processing queues rather than coordinated action among authors, theconversation.com reported.
Two papers utilizing the 2019 Guangdong samples failed to explicitly state they were reusing existing data, leading to interchanged sample names. These publication errors prompted formal corrections in journals including PLOS Pathogens and Nature, though the Hong Kong team’s paper featuring original Guangxi samples required no such corrections.
| Viral Strain / Sample | Discovery / Sampling Date | Genomic Similarity to SARS-CoV-2 |
|---|---|---|
| Guangdong Pangolin Coronavirus (2019) | Seized in 2019 (Data public Jan 2020) | ~90% whole genome (~99% in RBD region) |
| RaTG13 (Bat Coronavirus) | Published late January 2020 | 96.2% complete sequence |
| BANAL-20-52 (Bat Coronavirus) | Sampled July 2020 (Published autumn 2021) | 96.8% complete sequence |
Inventories of animals sold in Wuhan markets before the pandemic published in June 2021 contained no pangolins. Genetic studies of environmental samples collected from the Huanan seafood market in Wuhan in early 2020 revealed no genetic traces of pangolins.
Nevertheless, researchers continue to study these scaly mammals because they represent the only wild animals besides bats known to harbor distinct pre-pandemic coronavirus infections across Southeast Asia and southern China. Whether those infections occurred in natural habitats or during transport remains undetermined.
- bioRxiv. Virological est un site web où des chercheurs en virologie partagent leurs résultats.
- Nature.
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