The Ebola virus has been developing into an epidemic  in western African countries such as Guinea, Liberia and Sierra Leone since December of 2013. As of late, however, it has become a threat to other areas of the world, including the United States. American medical professionals infected with the virus returned to the U.S. after helping out with the epidemic in west Africa, and the deadly ailment has already caused a U.S. casualty since a case was first confirmed in Dallas, TX.

According to ABC News, Thomas Eric Duncan, who was being treated for Ebola in a confined ward in a Dallas hospital called the Texas Health Presbyterian Hospital, passed away at 7:51 a.m. on Oct. 8. Duncan was a Liberian citizen who had traveled to Texas to visit his family, and upon arrival, became the first person in America to be diagnosed with and lost to the sickness. Duncan’s family is distraught over the loss, and has thanked the medical professionals and community for their help and attempts to heal Duncan. Duncan’s girlfriend and several other people have been placed under quarantine, as they were exposed to Duncan when he was exhibiting symptoms of the disease.

Dallas mayor Mike Rawlings said they had hoped they would not lose him, and that his death is truly painful.

Rawlins has emphasized that precautions are being taken to keep Ebola from spreading in Dallas.

“We will stop the Ebola virus in its tracks from spreading into our community. I want to reinforce to the public, that this was an isolated incident of the Ebola virus; contracted by the individual while residing in another country,” he said.

Unfortunately, Rawlins’ hopes of stopping the devastating disease in its tracks may be endangered. In the first case of Ebola contracted while in the United States, one of Duncan’s nurses, Nina Pham, who only cared for Duncan while wearing protective gear, has tested positive for the illness. Those who have come in contact with her has been quarantined as well. According to CNN, the nurse was exposed to Duncan quite a bit during his time in the hospital, and her contraction of the virus is the result of a breach of protocol at the hospital. However, thus far the nurse has remained in stable condition. According to USA TODAY, the hospital where Duncan was treated is now under great scrutiny from a national nurse’s group, who claims the hospital was negligent in their care for Duncan and exposed him to other patients and hospital workers.

According to ABC Action News, a second hospital worker, Amber Vinson, who was exposed to Duncan during his sickness, has tested positive for Ebola. The Centers for Disease Control and Prevention (CDC) said that Vinson was on a plane on Oct. 13, the day before her diagnosis. The CDC is working to contact those who were on the Dallas/Fort Worth of Oct. 13, and the flight’s crew claim that Vinson exhibited no symptoms of the illness the day of the flight.