LAS VEGAS (AP) — Health officials have reported a second case of the new coronavirus in the Las Vegas area, bringing to four the total number of patients in Nevada.

Southern Nevada Health District spokeswoman Jennifer Sizemore told the Las Vegas Review-Journal the investigation of the new case of the COVID-19 respiratory illness in a Clark County resident is in preliminary stages. Patients have not been identified by name.

Sizemore didn’t immediately respond Monday to messages.

Nevada’s first two coronavirus cases were reported Thursday, including a man in his 50s who was being treated in isolation at a Veterans Administration hospital in North Las Vegas. Officials said he recently returned home after traveling to Texas and to Washington state, the epicenter of the outbreak in the U.S. with 18 deaths.

Washoe County officials reported the same day that a Reno-area man, also in his 50s, tested positive and was in stable condition in self-isolation at home. Another case was reported in the Reno area during the weekend.

Washoe County Health Officer Kevin Dick said Monday the new case is a man in his 30's who became ill after traveling recently to to Santa Clara, California.

Symptoms of the disease range from mild to severe, with some people developing pneumonia.