(Updates with new details on workers, experimental drug)
By Rich McKay
ATLANTA, Aug 4 (Reuters) - The second American aid worker who contracted the deadly Ebola virus while helping fight the disease in West Africa is in serious condition, but is expected to arrive in Atlanta on Tuesday for treatment, a relief organization said.
Missionary Nancy Writebol, 59, will fly on a medical aircraft from Liberia to be treated by infectious disease specialists in a special isolation ward at Emory University Hospital, according to Christian mission group SIM USA.
The specialists on Saturday began treating 33-year-old U.S. doctor Kent Brantly, who also returned home after being stricken with Ebola during the emergency response to the worst outbreak on record of the hemorrhagic virus, which has killed nearly 900 people since February.
Writebol and Brantly are believed to be the first Ebola patients ever treated in the United States. They served in Monrovia on a joint team run by Christian aid groups SIM USA and Samaritan's Purse and are returning separately because the plane equipped to transport them can carry only one patient at a time.
Writebol is in serious condition, SIM USA said on Monday.
"We are so grateful and encouraged to hear that Nancy's condition remains stable and that she will be with us soon," said Bruce Johnson, president of SIM USA.
"Her husband, David, told me Sunday her appetite has improved and she requested one of her favorite dishes - Liberian potato soup - and coffee," Johnson said in a statement.
Brantly's wife, who had returned home to Texas before he became ill, said in a statement late on Sunday that she had seen her husband and that he was in good spirits.
"He thanked everyone for their prayers and asked for continued prayer for Nancy Writebol's safe return and full recovery," Amber Brantly said.
SIM said a missionary group of two adults and six children it evacuated from Liberia due to the outbreak arrived on Sunday in Charlotte, North Carolina, where they will be housed temporarily on the organization's campus. None have shown symptoms of infection, the group said.
CNN reported on Monday that both Brantly and Writebol saw their conditions improve by varying degrees in Liberia after they received an experimental drug previously tested only on monkeys.
The drug was developed by San Diego-based private biotech firm Mapp Biopharmaceutical Inc. Shares for another company, Canada-based Tekmira Pharmaceuticals Corp, one of a few to have developed Ebola treatments advanced enough to be tested on people, slumped after the CNN report. [ID: L2N0QA0XK]
There is no proven cure for Ebola, and the death rate in the current epidemic is about 60 percent, experts say.
Standard treatment for the disease is to provide supportive care. Doctors at Emory will try to maintain blood pressure and support breathing of the workers, with a respirator if needed, or provide dialysis if they experience kidney failure, as some Ebola sufferers do.
The facility in Atlanta chosen to treat the two infected Americans was set up with the help of the U.S. Centers for Disease Control and Prevention.
The CDC has said it is not aware of any Ebola patient having been treated in the United States before. Five people entered the country in the past decade with either Lassa Fever or Marburg, both hemorrhagic fevers similar to Ebola.
White House spokesman Josh Earnest said there were no plans to stop flights to the United States from countries grappling with Ebola. Screening is being done to watch for travelers exhibiting symptoms, including some participants at a U.S.-hosted Africa summit in Washington.
Brantly and Writebol each had lived in Liberia since last year with their spouses and, in Brantly's case, two young children.
Brantly joined the Samaritan's Purse post-residency program after completing his residency in family medicine at John Peter Smith Hospital in Fort Worth, Texas, and then became part of the organization's medical team helping to fight Ebola.
Writebol, a mother of two from Charlotte, is longtime missionary who had been working for SIM USA as a hygienist who decontaminated the protective suits worn by medical workers inside the isolation ward at a treatment center in Monrovia.
None of the aid workers' family members have shown signs of illness, Samaritan's Purse and SIM USA have said.
Writebol's husband, a fellow missionary in Liberia, is expected to travel home separately in the next few days, SIM USA said. (Additional reporting by Mark Felsenthal; Writing by Daniel Wallis and Colleen Jenkins; Editing by Bill Trott and Eric Walsh)