Vietnamese-American nurse infected with Ebola despite wearing protective gear.

Nina Pham wore a mask, gloves, a gown, and a face shield while caring for Ebola patients. She tested positive for the virus, and authorities couldn't figure out how that happened.

Nurse Nina Pham. Photo: Facebook

"Something went wrong, and we need to find out what it was and why," said Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases.

Nina, 26, followed basic precautions when she joined a team of 50 doctors and nurses treating Thomas Eric Duncan, a Liberian patient, at a hospital in Dallas, Texas. Duncan died last week, and just one day later, the Centers for Disease Control and Prevention (CDC) announced that Nina had tested positive for the Ebola virus. She became the first person infected with the deadly virus on American soil.

According to CNN, Nina graduated from the nursing program at Texas Christian University in 2010. She only received her intensive care nurse certification on August 1st, less than two months before joining Duncan's treatment team.

Yesterday, Nina received a blood transfusion from Kent Brantly, an Ebola survivor. Brantly contracted the virus while working in Liberia.

Dr. Tom Frieden, director of the CDC, said it is unclear how Nina contracted Ebola and that a "protocol error" in patient care may have occurred.

Federal officials are reviewing these protocols, including the removal of protective equipment after contact with Ebola patients, and whether spraying disinfectant on healthcare workers as they leave isolation rooms is actually effective.

How did the virus spread?

CDC officials interviewed Nina several times and noted "inconsistencies" in the personal protective equipment she used, as well as the way she put it on and took it off.

According to Frieden, it's possible that when Nina removed her protective gear, some fluid containing the virus from the patient somehow came into contact with her. Or it could have happened during Duncan's kidney dialysis and intubation.

"You have to remove gloves, masks, or other items that have been contaminated with the virus without letting these tools come into contact with your hands, then your clothes, your face, or your skin—that's not easy to do," Frieden said.

Even taking extra precautions beyond CDC recommendations can increase the risk of infection. Nurses are permitted to wear two gloves in some situations, but wearing three gloves violates CDC guidelines because it increases the number of steps and prolongs the time spent removing protective equipment beyond what is necessary.

The CDC acknowledges that Nina's case is very concerning. "It's possible that in the coming days we will see more Ebola cases," Frieden said.

Other nurses who cared for Duncan are also being monitored because they may be like Nina. They will be checked twice a day for symptoms of fever.

The public areas around Nina's apartment building have also been disinfected, and her neighbors have been informed of the situation. However, officials say the public should not be overly concerned about the outbreak.

Tom Ha, a friend of Nina's family, described her as someone who always "put the interests of others before her own." "That's a philosophy she shared with her family," he said. "They were always helpful and proud to help others."

According to VnExpress.