A viral outbreak at a retirement center has left two people dead and sickened more than 40 residents and workers, authorities said.

Clark County health officials said Thursday they have asked the 180 residents of the Cascade Inn to stay in their rooms and urged friends and family not to visit until the outbreak of norovirus runs its course. Social activities have been canceled.

The voluntary quarantine will remain in effect until four days after the last new diagnosis — perhaps another week, said Marni Storey, manager of the county health department's infectious disease program.

One of the patients died late Wednesday and the other Thursday morning, officials said.

The norovirus is common and often takes the form of a mild stomach disorder. Symptoms can include nausea, diarrhea and vomiting.