DALLAS — As many as 18 individuals in the Dallas area are under observation by Dallas County health officials after coming in contact with a patient confirmed to be infected with the Ebola virus, officials said Wednesday.

The people being monitored include five individuals in the “immediate household” the patient was staying at while visiting from the West African nation of Liberia and five school-age children who were in contact with the patient after he was sent home from Texas Health Presbyterian Hospital of Dallas. The patient had disclosed to staff that he had traveled from an area affected by the recent outbreak of the Ebola virus, which has killed 3,000 people.

The patient, who has been identified as an adult male, arrived in the U.S. from Liberia on Sept. 20, showing no symptoms before the flight or when he arrived. He developed symptoms on Sept. 24 and first sought care for a fever and abdominal pain at the Texas Health Presbyterian emergency room on Sept. 26.

During a news conference Wednesday in Dallas, Dr. Mark Lester, executive vice president for Texas Health Resources, the parent company of Texas Health Presbyterian Hospital, confirmed that the patient volunteered during that visit that he had traveled to Africa when asked by a hospital nurse who was using a checklist that “was in place for Ebola in this hospital for several weeks.”

The Texas Tribune thanks its sponsors. Become one.

“That nurse was part of a care team, and it was a complex care team taking care of him in the emergency department. Regretfully that was not fully communicated throughout the full team, and as a result the full import of that information wasn’t factored into the clinical decision-making,” Lester said.

The patient was sent home with a prescription for antibiotics after hospital staff assessed his condition as a “low-grade viral disease.” The patient’s contact with the five children occurred days before he was admitted to the hospital on Sept. 28 and  placed in isolation.

Because he had already developed symptoms, the patient was infectious during the first hospital visit. Ebola is not easily spread because it can only be transmitted through direct exposure to the bodily fluids — including blood, sweat, saliva, vomit and diarrhea — of someone who is carrying the virus and is showing symptoms.

Mike Miles, superintendent of the Dallas Independent School District, said at the news conference that the students are being monitored in their homes but are not showing symptoms associated with the Ebola virus. The five students, who were not identified, attend Conrad High School, Tasby Middle School, Dandy Rogers Elementary School and Hotchkiss Elementary School.

Dallas County Health and Human Services officials, who are monitoring the individuals who came in contact with the infected Ebola patient, notified the school district Wednesday morning about the students’ contact with the patient at a family home “over the weekend.” The students were in class earlier this week.

It is expected that the individuals who came in contact with the infected Ebola patient will be observed for up to 21 days by county health officials and a team from the federal Centers for Disease Control and Prevention.

The Texas Tribune thanks its sponsors. Become one.

Officials indicated that the individuals who were in contact with the patient are not in quarantine. Zachary Thompson, director of the Dallas County health department, said the individuals were only given “recommendations” about limiting contact with other individuals.

“If they don’t follow our recommendations, more stringent guidelines will be put in place,” Thompson said. “That’s something we need to discuss in a more legal aspect.”

Officials did not provide additional details of what those guidelines would be and who would enforce them.

Gov. Rick Perry emphasized during the news conference that residents should not panic about a potential spread of the virus, saying it was likely it would be contained to the current case. Federal and state officials have reiterated this point since the Ebola case was first confirmed on Tuesday.

“This case is serious,” Perry said. “Rest assured that our system is working as it should.”

Representatives for the governor did not immediately respond to a request for comment about the hospital’s actions.

Jay Root reported from Dallas, and Alexa Ura reported from Austin.