CHARLOTTE, N.C. -- Three American missionaries, including the husband of Ebola patient Nancy Writebol, returned home from Liberia Sunday night and will remain quarantined to make sure they don't develop the disease.
David Writebol and the two others, whose names were not released, were working in Liberia with the Charlotte-based SIM USA missionary group. SIM USA says the two other missionaries were doctors who treated Ebola patients at a medical center in Monrovia, Liberia, where Nancy Writebol assisted.
The quarantine will continue for 21 days after the point when they were last exposed to people infected with the Ebola virus, the North Carolina Department of Health and Human Services said. Ebola can have up to a 21-day incubation period.
None of the three is sick or shows any signs of having Ebola, SIM USA president Bruce Johnson said in a statement. They underwent medical screenings and were cleared before they boarded the private charter flight home, and were checked again as soon as they arrived, the group said.
"We will continue to cooperate and collaborate with [public health officials] and adhere strictly to their guidelines in the return of our missionaries to the United States," Johnson said.
SIM USA said the three missionaries will be staying in a private section of the group's Charlotte compound until the quarantine period is over.
Before he left Liberia, David Writebol spoke to reporters by telephone and said he hoped to be reunited with his wife as soon as doctors allowed. CBS News chief medical correspondent Dr. Jon LaPook asked Writebol if he was waiting to see if he was infected, and Writebol replied, "Yes, I am taking my temperature every day."
Nancy Writebol was taken to Emory University Hospital in Atlanta last week after contracting Ebola in Liberia. Her husband said she is showing signs of improvement after being given three doses of an experimental serum.
The other American Ebola patient, Dr. Kent Brantly, 33, of Fort Worth, Texas, is also being treated at Emory. Brantly issued a statement Friday saying, "I am growing stronger every day, and I thank God for His mercy as I have wrestled with this terrible disease."
Since the Ebola outbreak began in March, the virus has killed at least 961 people in the West African countries of Liberia, Sierra Leone, Guinea and Nigeria.