She is credited with having curbed a wider spread of the Ebola virus in Nigeria by placing the patient zero, Patrick Sawyer, in quarantine despite pressures from the Liberian government.
She is known for preventing the Nigerian index case from leaving the hospital at the time of diagnosis, thereby playing a key role in curbing the spread of the virus in Nigeria. On 4 August 2014, it was confirmed that she had tested positive for Ebola virus disease and was being treated. Adadevoh died in the afternoon of 19 August 2014.She was survived by her husband Afolabi and son Bankole among other relatives.

Dr. Adadevoh correctly diagnosed Liberian Patrick Sawyer as Nigeria’s first case of Ebola at First Consultant Hospital in Lagos, Nigeria in July 2014. Dr. Adadevoh kept Patrick Sawyer at hospital despite his insistence that he had a bad case of Malaria. Sawyer wanted to attend a business conference in Calabar, Nigeria. Adadevoh led the team who oversaw the treatment of Patrick Sawyer a Liberian, the first patient diagnosed with Ebola in Nigeria. Dr. Adadevoh also kept Patrick Sawyer at the hospital despite receiving a request from a Liberian ambassador to release him from the hospital. Dr. Adadevoh tried to create an isolation area, despite the lack of protective equipment, by creating a wooden barricade outside Patrick Sawyer's door. Her heroic effort saved the nation from widespread infection, as of these events, Nigerian Doctors were on strike, and that could have caused severe crises.

The professionalism and thorough medical examination carried out by Dr. Ameyo Adadevoh was impeccable Adadevoh also provided staff with relevant information about the virus, procured protective gear and quickly contacted relevant officials. As a result of her report, the Nigerian government declared a national public health emergency and the Nigerian Ministry of Health set up an Ebola Emergency Operations Center.WHO declared Nigeria to be Ebola free on October 20, 2014.