The World Health Organization declared Liberia free of Ebola on Saturday, making it the first of the three hardest-hit West African countries to bring a formal end to the epidemic.
“The outbreak of Ebola virus disease in Liberia is over,” the W.H.O. said in a statement read by Dr. Alex Gasasira, the group’s representative to Liberia, in a packed conference room at the emergency command center in Monrovia, the capital.
Just before Dr. Gasasira’s statement, Luke Bawo, an epidemiologist, showed a map depicting all of Liberia in green with the number 42 superimposed on it. This represented that two maximum incubation periods of the virus, a total of 42 days, had passed since the safe burial of the last person confirmed to have had Ebola in the country, fulfilling the official criteria for concluding that human-to-human transmission of the virus has ended.
The room, packed with reporters, workers from Doctors Without Borders and other aid agencies and dignitaries, including the American ambassador to Liberia, Deborah R. Malac, burst into applause, and some people cried, according to health officials who were present.
The president of Liberia, Ellen Johnson Sirleaf, then held a moment of silence for those who had died. She thanked Liberians who had fought Ebola and expressed her gratitude to the country’s international partners and others around the world “whose hearts were with us.” Ms. Johnson Sirleaf added, “Let us celebrate, but stay mindful and vigilant.”
Then she began shaking hands, a mundane act that seemed monumental in a country where people have been cautioned for months not to touch one another.
Throughout the morning, the president, wearing sneakers and a baseball cap emblazoned with the Liberian flag, visited hospitals and met with orphans, widows and survivors of Ebola.
“The health workers are dancing and clapping and singing ‘no more Ebola,’ ” Dr. Gasasira said by phone as he traveled with Ms. Johnson Sirleaf.
The W.H.O. says there were more than 3,000 confirmed Ebola cases in Liberia, and 7,400 suspected or probable cases, with more than 4,700 deaths estimated to have occurred since the outbreak was declared there in March 2014. Among the dead were 189 health care workers.
Tolbert Nyenswah, a senior Liberian health official who leads the country’s Ebola response efforts, said in an interview that the end of the epidemic was “a victory for Liberia and Liberians.”
“The only caution,” he said, is that “we are very much concerned about Guinea and Sierra Leone.”
The White House congratulated the people of Liberia but echoed those worries. It pledged to help rebuild the country.
On Saturday, the streets in downtown Monrovia, where ambulances had roared in August and September, were quiet and calm. Many people expressed a sense of relief.
“Thank God,” said Nathan Gull, who works at a hospital that lost staff members to the disease.
Abubakar Jabbie, a 32-year-old money changer, said, “We were in darkness — no trading, nothing was moving in this country.”
In the past week, Guinea and Sierra Leone each reported nine cases of the disease, the lowest weekly total this year. Dr. Bruce Aylward, head of the W.H.O.’s Ebola response efforts, cautioned that hidden chains of transmission were probably occurring in those two countries. “We don’t know where that virus is,” he said. Dr. Aylward said it had taken Liberia several months to get to zero cases after reaching single digits.
Mr. Nyenswah said Liberia would continue many of the measures that helped the country vanquish the epidemic, including surveying border areas for sick travelers, testing all dead bodies for the virus and conducting burials with specially trained teams wearing protective gear.
“We are being extremely cautious,” Dr. Bernice Dahn, the country’s incoming health minister, said in an email. She said the country’s priority now was to build its critically deficient health care work force. “Ebola highlighted our health system’s weaknesses,” she said.
An important question for Liberia is whether it can now draw foreign companies back to the country, whose economy has been battered. British Airways, for instance, which came under fire from aid officials after it and several other airlines stopped flying to Liberia and Sierra Leone last August, has not resumed services.
Last week, the Centers for Disease Control and Prevention stopped advising American citizens to avoid nonessential travel to Liberia, instead recommending that they “practice enhanced precautions” when going there.
“The country can get back to business,” Dr. Thomas R. Frieden, director of the disease centers, said Friday in an interview. “It’s a tribute to the enormous hard work done by Liberians, by the C.D.C., by partners throughout the U.S. government and the international community.”
For the time being, however, travelers from Liberia to the United States will still be subject to a 21-day monitoring program. “That’s something we’ll be discussing in the coming days with other parts of the U.S. government,” Dr. Frieden said.
The W.H.O. has recommended that Liberia maintain an additional three months of “heightened surveillance” for Ebola because of the continuing outbreak in neighboring countries, as well as the possibility that Ebola could re-emerge via sexual transmission from survivors.
On Friday, the W.H.O. revised its guidelines for survivors, urging men and their partners to abstain from sex or to practice protected sex for at least six months or until two semen tests have been negative for traces of the virus. That advice follows recent scientific evidence suggesting that the last patient to fall ill and die of Ebola in Liberia may have caught the virus from her boyfriend many months after his recovery. Studies have shown that Ebola can persist in semen for some time, even after a man has completely recovered and poses no risk to the general public.
The origins of the outbreak in West Africa remain undetermined, and some scientists believe Ebola is likely to be circulating in wildlife in the region. Four of six countries that suffered previous Ebola epidemics had a recurrence of the disease within three years, the W.H.O. said.
There are signs that some hygienic habits that were adopted during the epidemic may be sustained in Liberia, including hand-washing programs at schools. “That practice should become a way of life for us,” said Iris Martor, a nurse and the program director for the nonprofit organization More Than Me, which runs an academy for girls in the West Point slum area of Monrovia. “If we forget ourselves and go back to the careless way of life, there could be another outbreak,” Ms. Martor added.
One of Ms. Martor’s students, Benetter Kun, 18, is the daughter of Liberia’s last Ebola patient, Ruth Tugbah, who died at a treatment unit in late March. For Ms. Kun, as with many family members who lost loved ones, the end of the epidemic was bittersweet.
“It’s a sad moment for me and my family because we are not complete,” she said.