Boiled pangolin for lunch? The rampant trade that could spark a new pandemic

According to a paper in the journal Frontiers in Immunology, pangolins have fewer interferon receptors than humans and other mammals. This means their innate immune response does not go into an inflammation overdrive as soon as they’re infected, contributing to a “switch from resistance to tolerance of viral infections”.

“Pangolins have an unusual immune system and appear to lack parts of certain innate antiviral pathways,” said Dr Filip Claes, head of the Emergency Center for Transboundary Animal Diseases at the UN’s Food and Agriculture Organisation. “In practical terms, this likely means they mount a less rapid or less inflammatory early response to some viral infections. That may allow certain viruses to persist longer without causing severe disease.”

But he stressed that this tolerance is far lower than in bats – one review published in 2024 found the flying mammals host over 4,100 distinct viruses, including deadly pathogens like Ebola, Nipah and Sars.

This is because bats’ immune system has been suppressed, partly because of the stress physiology of flying, which allows them to co-exist with viruses for long periods of time – and gives pathogens ample opportunity to replicate, recombine and evolve. Bats also travel widely and live in colonies with millions of others, allowing diseases to spread between them.

“Pangolins are not considered a primary reservoir because they are relatively rare, solitary animals in the wild,” said Dr Claes. “They are not known to maintain stable, self-sustaining viral populations across large populations over time, and there is no strong evidence of long-term virus-host co-evolution, as seen in bats.”

Instead, pangolins are deemed high risk for zoonotic diseases because of the characteristics of the illegal wildlife trade.

“They are captured, stressed, transported long distances, and often mixed with other wildlife and humans. These conditions create ideal opportunities for pathogen transmission, adaptation, or recombination – and repeated human exposure,” said Dr Claes.