The US is ramping up efforts to catch the Wuhan virus and stop it from spreading. But there are still gaps in the net.

On Tuesday, the US confirmed the first confirmed case of the Wuhan virus in the country — a man now being treated in Everett, Washington. The US government also announced more widespread screening measures at five airports, meant to slow the spread of the disease. The US plans to reroute all Wuhan passengers — even indirect ones —to one of these five airports for screening. But even this has limits. Other places in China and other countries have cases too. Plus there are potentially more s...