Texas Ebola patient Thomas Eric Duncan has been listed in critical condition. Officials at Texas Health Presbyterian Hospital Dallas changed the patients prognosis after his symptoms worsened on Saturday night.

Duncan traveled back to the United States from Liberia last month. The patient began showing symptoms of the disease after he had already arrived in Dallas.

Health officials from the CDC were forced to act quickly, developing a database of nearly 50 people who had come in contact with Duncan since his return. Officials revealed that nine people were believed to be at a higher risk of contracting the device. None of those people have shown symptoms at this time. The Ebola virus has an incubation period of 2 to 21 days.

On Friday a hazardous-materials crew hauled out items from Duncan’s apartment.

U.S. Officials have stated on numerous occasions that they believe controlling the virus in the United States is possible, however, following Duncan’s hospitalization, new concerns over the diseases spread began to occur on social media. Health officials on Saturday said they have received more than 100 inquiries about suspicious cases in the last several months.

Ebola is not airborne and can only be spread through direct contact with bodily fluids, including blood, sweat, vomit, feces, urine, saliva or semen.

Thomas Eric Duncan arrived in Dallas on September 20, and several days later he showed symptoms of the disease. After visiting  Texas Health Presbyterian Hospital, he was sent home. Two days later he returned to the hospital by way of ambulance, and he has remained in isolation in an intensive care unit since his second arrival to the health facility.

Health officials are now urging hospitals to take a more robust travel history of patients to ensure they have not traveled to an Ebola-stricken part of the world. It wasn’t until Duncan returned two days later, that the hospital learned of his trip to West Africa. In Duncan’s case, a system breakdown failed to alert hospital officials to his travel itinerary.

Health officials have not revealed any new details about Texas’ Ebola patient at this time.