FREETOWN, Sierra Leone (AP) -- The president of Sierra Leone declared a public health emergency as the Ebola crisis blamed for nearly 700 deaths deepened across West Africa, vowing to quarantine sick patients at home and conduct house-to-house searches for others who may have been exposed.
The announcement from President Ernest Bai Koroma late Wednesday came as neighboring Liberia also ramped up its efforts to slow the virulent disease's spread, shutting down schools and ordering most public servants to stay home from work.
The U.S. Peace Corps also was evacuating hundreds of its volunteers in the affected countries. Two Peace Corps workers are under isolation outside the U.S. after having contact with a person who later died of the Ebola virus, a State Department official said.
Ebola has been blamed for more than 670 deaths in four West African countries this year, and has shown no signs of slowing down particularly in Liberia and Sierra Leone. Among the dead was the chief doctor treating Ebola in Sierra Leone, who was to be buried Thursday.
The government said Dr. Sheik Humarr Khan's death was "an irreparable loss of this son of the soil." The 39-year-old was a leading doctor on hemorrhagic fevers in a nation with very few medical resources.
Ebola cases first emerged in the nation of Guinea back in March, and later spread across the borders to Liberia and Sierra Leone. The outbreak is now the largest recorded in world history, and has infected three African capitals with international airports. Officials are trying to step up screening of passengers, though an American man was able to fly from Liberia to Nigeria, where authorities say he died days later from Ebola.
Ebola has no vaccine and no specific treatment, with a fatality rate of about 60 percent. But experts say the risk of travelers contracting it is considered low because it requires direct contact with bodily fluids or secretions such as urine, blood, sweat or saliva. Ebola can't be spread like flu through casual contact or breathing in the same air.
Patients are contagious only once the disease has progressed to the point they show symptoms, according to the World Health Organization. The most vulnerable are health care workers and relatives who come in much closer contact with the sick.
Associated Press writers Krista Larson in Dakar, Senegal; and Jonathan Paye-Layleh in Monrovia, Liberia contributed to this report.