Coronavirus has been spreading for weeks in the US undetected, researchers say

Officials suggest 'cryptic transmission' may be the cause of an apparent outbreak in Washington state as fears grow of a potential pandemic

The coronavirus has been spreading in Washington state undetected, according to a new analysis, as health officials nationwide increasingly fear there are far more cases of the deadly virus that have not yet been confirmed.

Trevor Bedford, a computational biologist at the Fred Hutchinson Cancer Research Centre in Seattle, spearheaded a genetic analysis of two virus samples after multiple cases of the mysterious illness were confirmed throughout Washington in recent weeks.

His findings suggested the state was already facing a “substantial outbreak” that had not been previously detected because initial tests for coronavirus were limited to people who had recently visited China.

The virus samplings came from two patients living in the state, according to Washington Post: one of the patients, who was the first person identified to have coronavirus in the US, had recently travelled to China before returning to Snohomish County.

The second patient had not recently travelled and was not known to have any exposure to the coronavirus.

Such findings indicated that “cryptic transmission” had been occurring in Washington over the last six weeks, according to Mr Bedford.

In announcing his findings on Twitter, Mr Bedford wrote: “I believe we're facing an already substantial outbreak in Washington State that was not detected until now due to narrow case definition requiring direct travel to China."

An official with the US Centre for Disease Control told the Washington Post the centre was in contact with Mr Bedford and that more analysis would need to be done to determine how the virus has spread throughout Washington, calling the findings “far from definitive”.

Still, the genetic similarities between both strains assessed in Mr Bedford’s findings could suggest the virus had been spreading in Washington ever since the first patient returned to Snohomish County in January.

Both patients involved in the assessment were not known to have contact with each other before testing positive for the virus.

At least two people in the US died as a result of the coronavirus, as the death toll surpassed 3,000 worldwide, with the majority of those occurring in China where the coronavirus originated.

US health officials have meanwhile said the virus spreading throughout the country was all but inevitable, as the White House and federal agencies prepared for the outbreak to “substantially” impact everything from the strength of the economy to everyday life.

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