There is some welcome good news about the Ebola epidemic today: The outbreak in Nigeria is officially over. Today the World Health Organization (WHO) reported that the country has gone the required 42 days since the last new case was isolated and is “free of Ebola virus transmission.” The news follows several other hopeful notes. On Friday, Senegal received the same designation, after following up on contacts from a case imported from Guinea. Yesterday, the U.S. Centers for Disease Control and Prevention (CDC) said that close contacts of the first case diagnosed in the United States had completed their 21-day isolation period and were uninfected. In addition, a nurse in Spain and a Norwegian worker for Doctors Without Borders have both recovered from their infections.
Nigeria’s success at stopping the outbreak was due to a rapid response by health authorities, as well as a healthy dose of good luck—a patient who exposed many people to the virus but infected few. As the WHO statement details, the outbreak began when a Liberian man infected with the virus flew to Lagos for a meeting. He was visibly ill before boarding the plane, vomited on the flight, and collapsed on arrival. He died a few days later, but infected several of the people who met him at the airport as well as nine health care workers.
One of the close contacts escaped the epidemiological monitors who were tracking people who had been exposed. He secretly flew to Port Harcourt, the capital of Rivers state in Nigeria and was treated by a private doctor in a hotel room. He survived and flew back to Lagos, but the doctor became infected. The doctor continued working after developing symptoms, and he did not tell anyone he had had contact with an Ebola patient even after he was admitted to a hospital. He was diagnosed with Ebola only 5 days after his death. His behavior exposed at least 200 people to the virus, 60 of whom WHO considered high-risk or very high-risk exposures. Just a few of those became infected, however: his wife and his sister, who both recovered, and one other patient at the hospital where he was treated, who died.
*The Ebola Files: Given the current Ebola outbreak, unprecedented in terms of number of people killed and rapid geographic spread, Science and Science Translational Medicine have made a collection of research and news articles on the viral disease freely available to researchers and the general public.