Las Vegas casinos, open for months now, are a likely hotbed for the spread of COVID-19. For many reasons, contact tracing has proved next to impossible as tourists return to homes across the U.S.

When it comes to COVID-19, what happens in Vegas doesn’t stay in Vegas.

Las Vegas casinos reopened June 4, and they have become a likely hotbed for the spread of the novel coronavirus, public health experts said. But if tourists return home and then test positive for COVID-19, the limitations of contact tracing in the midst of a pandemic make it unlikely such an outbreak would be identified.