How dog coronavirus jumps to humans

US researchers have identified a shift that occurs in canine coronavirus that may provide clues as to how it transmits from animals to humans.

A new canine coronavirus was first identified in two Malaysian human patients who developed pneumonia in 2017-18. A group of other scientists isolated the canine coronavirus, sequenced it, and published their findings in 2021.

Now, a team led by researchers from Cornell and Temple University in the US has identified a pattern that occurs in a terminus of the canine coronavirus spike protein - the area of the virus that facilitates entry into a host cell.

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This pattern shows the virus shifts from infecting both the intestines and respiratory system of the animal host to infecting only the respiratory system in a human host.

The researchers identified a change in the terminus - known as the N terminus - a region of the molecule with alterations also detected in another coronavirus, which jumped from bats to humans, where it causes a common cold.

"This study identifies some of the molecular mechanisms underlying a host shift from dog coronavirus to a new human host, that may also be important in the circulation of a new human coronavirus that we previously didn't know about," said Michael Stanhope, Professor of public and ecosystem health at Cornell.

In the study, published in the journal Viruses, the researchers used state-of-the-art molecular evolution tools to assess how pressures from natural selection may have influenced the canine coronavirus' evolution.

The same variant of canine coronavirus found in Malaysia was also reported in 2021 in a few people in Haiti, who also had respiratory illness.

Stanhope believes more study is needed to understand if the viral shifts and jumps to humans occurred spontaneously in different parts of the world or if this coronavirus has been circulating for perhaps many decades in the human population without detection.