The West African nation where last year's deadly Ebola epidemic began has been declared free of the virus by the World Health Organization, two years after the first transmissions were detected there.Guinea was home to the first transmissions of the outbreak, which sickened an estimated 28,000 and left more than 11,000 dead across four West African countries in 2014.But in November, the last known patient, an infant named Nubia whose infected mother died the day of her birth , was released from a clinic after overcoming the virus. Nubia is believed to be the first infant born to an infected mother to survive Ebola, according to Doctors Without Borders.

There have been no new cases in the 42 days since Nubia's recovery, a milestone that allowed health officials to officially declare the country free of Ebola transmissions.The Guinea announcement was the latest positive news in the region's fight to bring an end to the debilitating outbreak.“This is the first time that all three countries — Guinea, Liberia, and Sierra Leone — have stopped the original chains of transmission that were responsible for starting this devastating outbreak two years ago,” Dr. Matshidiso Moeti, WHO regional director for Africa, said in a statement . “I commend the governments, communities, and partners for their determination in confronting this epidemic to get to this milestone. As we work towards building resilient healthcare systems, we need to stay vigilant to ensure that we rapidly stop any new flares that may come up in 2016.”Still, officials caution that countries and health workers must remain vigilant amid concerns that "flare-ups" of new cases could emerge. It is believed that traces of Ebola can remain in the systems of some survivors for nine to 12 months.“The coming months will be absolutely critical,” Dr. Bruce Aylward, special representative of the director-general for the Ebola Response, WHO, said in a statement. “This is the period when the countries need to be sure that they are fully prepared to prevent, detect, and respond to any new cases.The Ebola outbreak spread through multiple countries throughout 2014, becoming the largest in history, according to the Centers for Disease Control and Prevention . Women faced an especially great risk, pubic health experts warned , because their traditional roles as caretakers put them in direct contact with possibly contagious family and friends, as well as contaminated materials.