A third case of travel-related COVID-19 was confirmed in a San Antonio resident Sunday evening.

The San Antonio Metropolitan Health District said the person who contracted the virus recently traveled to Spain, where the number of cases has increased dramatically in recent days.

A detailed investigation into who the person has been in contact with is underway, and affected individuals will be notified. The person is currently in isolation from the public, Metro Health officials said.

In an effort to minimize the number of local cases, Mayor Ron Nirenberg on Friday declared a second public health emergency, as a previous declaration on March 2 expired after seven days. The new declaration prohibits indoor and outdoor gatherings of 500 people or more and “strongly recommends” against gatherings with more than 250 people.

“Based on what we know about the spread of this disease and any other, limiting public gathering is our first line of defense,” Nirenberg said.

Following the declaration, San Antonio school districts extended spring break for students, universities are holding classes online, and local businesses are asking employees to work from home in an effort to do what epidemiologists call “flattening the curve” of the pandemic. The idea is to increase social distancing to slow the spread of the virus and to avoid a large spike in the number of people getting sick all at once.

“We are working to contain the spread,” said Metro Health Director Dawn Emerick. “Our community can help minimize the spread of the virus by practicing good hygiene habits, social distancing, and staying home if they are sick.”

Metro Health officials are asking anyone showing symptoms of COVID-19, which includes fever, shortness of breath, and a runny nose, to not visit emergency rooms for testing and instead seek care from a primary care physician or urgent care provider, as a health care provider must order the test after ruling out flu and other respiratory illnesses.

The new case confirmed in San Antonio is the 53rd in Texas, not including repatriated cruise ship passengers, according to the Department of State Health Services.

In addition to the San Antonio diagnoses, the Centers for Disease Control and Prevention confirmed Saturday that a repatriated U.S. citizen who arrived at Joint Base San Antonio-Lackland last week tested positive for COVID-19. That person was one of two taken to the Texas Infectious Disease Hospital for testing last week.

Roseanna Garza reports on health and bioscience for the San Antonio Report.