The chairman of the US’s most important conservative conference, CPAC, has called for calm after reports he was exposed to a person infected with coronavirus before shaking hands with Donald Trump.

Matt Schlapp, who chairs the American Conservative Union, sent his message cautioning against panic as it emerged that an attendee at February’s conference had tested positive for the virus.

Writing on Twitter, Mr Schlapp told conference attendees that all was well.

“Woke up today and all the Schlapp’s are healthy. Same for entire CPAC staff …

“The State of Maryland did 2000 screenings around the Gaylord [conference venue] and found nothing concerning. We have no symptoms. Stay calm USA! Check your temp, if elevated call your doc.”

In a later tweet, he reiterated that the government had yet to call for attendees to take any unusual measures.

“We still have just one person who came to CPAC w/ Corona. He is being treated. NO NEW CASES. Department of Health has not called for any restrictions or quarantines. The key is symptoms. If you don’t have any that’s great news. If concerned check your temp. CPAC community is [thumbs up].”

This year’s conference was held in Washington, DC on 26-29 February, and several conference attendees are now in self-isolation. Among them are Texas senator Ted Cruz and Arizona congressman Paul Gosar.

In a twitter thread, congressman Gosar said that he and three of his senior staff are officially under self-quarantine “after sustained contact at CPAC with a person who has been hospitalised with the Wuhan virus".

“We are all asymptomatic and feel great. But we are being proactive and cautious.”

Mick Mulvaney says the United States is prepared for COVID-19 outbreak at CPAC

Others in Congress are also taking precautionary measures. A spokesman for Wyoming’s Liz Cheney said she declined to attend a Republican leadership retreat in the interests of safety: “Many of us have people in our families who are particularly vulnerable and, after consulting with physicians, Liz determined the best approach is to limit participation in non-essential gatherings.”