Public Health Emergency of International Concern second PHEIC was issued in May 2014 with the resurgence of polio after its near-eradication, deemed "an extraordinary event." On Friday, August 8, 2014, the World Health Organization declared its third Public Health Emergency of International Concern in response to the outbreak of Ebola in Western Africa. On Monday, February 1, 2016, the World Health Organization declared its fourth PHEIC in response to clusters of microcephaly and Guillain–Barré syndrome in the Americas, which at the time were suspected to be associated with the ongoing outbreak of Zika virus. Later research and evidence bore out these concerns; in April, the WHO
Ebola virus disease in Nigeria health care workers who had cared for Sawyer. In all, 529 contacts had been followed and of that date they had all completed a 21-day mandatory period of surveillance. On 9 October 2014, the European Centre for Disease Prevention and Control (ECDC) acknowledged Nigeria's positive role in controlling the effort to contain the Ebola outbreak. "We wish to thank the Federal Ministry of Health, Abuja, Nigeria, and the staff of the Ebola Emergency Centre who coordinated the management of cases, containment of outbreaks and treatment protocols in Nigeria." Nigeria's quick responses, including intense and rapid contact tracing, surveillance of potential