A second Ebola virus case in Dallas involves Thomas Eric Duncan's female health caregiver

Dallas has a second ebola virus infected case as a female health care worker was tested positive for the virus in a preliminary test administered last Saturday. The test came after the health worker showed signs associated with the dreaded disease.

It was discovered that Dallas's second ebola case provided health care services to Thomas Eric Duncan, the first person diagnosed with ebola in the U.S., according to reports from NBC News.

Records from the hospital show that Duncan was admitted to Texas Health Presbyterian Hospital on September 28, and it is possible that the health worker was infected after she had contact with Duncan, exposing herself to the virus.

NBC News said that the worker, whose name was requested to be withheld by her family was not among the 48 people undergoing a 21-day monitoring period after having been identified to have had contact with Duncan during his treatment.

Dr. Thomas Frieden, director of the federal Centers for Disease Control and Protection (CDC), in a news conference in Atlanta, expressed concerned that others not under the monitoring program might have been exposed as well.

He said the "CDC was working to identify other health care workers who also might have also come in contact with Duncan." He recommended hospitals to keep health care workers treating potential Ebola patients to a minimum.

Meanwhile, the hospital's officials who were also at the news conference said that protective gears, which include gown, gloves, mask and shield were worn by the afflicted health worker while administering health care services to Duncan, who died Wednesday because of the disease.

After tracking those who have had contact with the female health worker, a total of 19 people are being monitored for symptoms of ebola, including one who is already put in isolation, according to NBC News.

Dailymail also reported that the Dallas home of the worker has also "been sealed off with a police guard outside, and her car seized as reverse 911 call is sent out to a four-block radius to warn residents of risk."

The cause of the contagion was blamed by Dr. Frieden to a possible "breach of protocol" by the involved hospital when the hospital staff sent Duncan home the first time he came in for treatment.

Frieden opened the possibility that there would be people arriving to the U.S. with ebola, infecting other people, but is confident that the disease could be put under control.

The World Health Organization said that, as of Friday, more than 4,000 people in West Africa have already died of the disease. Almost all of those deaths have been in the three worst-affected countries, Liberia, Sierra Leone and Guinea.

Ebola spreads through close contact with an infected person's bodily fluids, such as saliva, urine, feces, blood, sweat, vomit, or semen. Symptoms include fever, flu-like body aches and abdominal pain, vomiting, and diarrhea.