Final answer:
Ebola first infected humans in 1976 in Central Africa. The largest outbreak was from 2014 to 2016 in West Africa, with significant cases in Guinea, Sierra Leone, and Liberia. The first U.S. case during this outbreak was diagnosed in Dallas, Texas, in September 2014.
Step-by-step explanation:
The first known cases of Ebola infecting humans occurred in 1976 in Central Africa, specifically in areas that are now part of the Democratic Republic of Congo. Later, the most extensive Ebola epidemic occurred between 2014 and 2016, predominantly affecting West African countries such as Guinea, Sierra Leone, and Liberia. This epidemic resulted in over 28,000 cases and 11,302 deaths, according to the CDC 2020 report.
In the United States, the first case associated with this epidemic was Thomas Eric Duncan, who arrived in Dallas, Texas, on September 24, 2014, showing symptoms consistent with Ebola infection. Despite initially being sent home with a misdiagnosis, he was later confirmed to be infected with the Ebola virus. The disease is highly contagious once symptoms are present and can be spread through direct contact with bodily fluids of an infected individual.