Ebola timeline: tracking a deadly virus

With startling regularity, Ebola, a disease that causes deadly hemorrhaging, has made headlines over the past several decades. Ebola disease is caused by a group of viruses known as orthoebolaviruses. The most severe outbreak of Ebola disease was in 2014, when nearly 30,000 people contracted the virus and more than 11,000 died from the disease across the West African nations of Guinea, Liberia, and Sierra Leone.

But you may not know that 2014 wasn’t the only time the virus became international news—nor that it was the first time it was reported in the United States. Read on for a timeline of significant Ebola outbreaks since the disease was first discovered nearly 50 years ago.

The first person to be diagnosed with Ebola disease showed symptoms after being treated for malaria near the Ebola River in Zaire (now the Democratic Republic of the Congo). Of the 318 cases that followed in Zaire that year, nearly all had either received injections at the same hospital or had close contact with another patient. The clinic was closed and 280 people died.

Monkeys imported from the Philippines and infected with Reston virus, a strain of orthoebolavirus, introduced the virus in Virginia, Pennsylvania, and later, Texas. None of the lab workers who came into contact with the animals became sick. More study of Reston virus is needed to understand its dangers to humans.

After eating a chimpanzee found dead in the forest, a group of Gabonese hunters contracted Ebola disease. More people became ill a few months later, again contracting the virus from a dead chimpanzee. One healthcare worker from South Africa treating Gabonese patients fell ill and a nurse treating him contracted the virus and died. In all, at least 67 people died from the epidemic between Gabon and South Africa.

Outbreaks of various strains of orthoebolaviruses occurred in Uganda, Gabon, and Republic of the Congo. Of the 727 reported cases, 478 people died.

Starting in March 2014 and continuing through much of 2015, Ebola outbreaks caused an estimated 11,308 deaths in several African countries, including Guinea, Liberia, Sierra Leone, Nigeria, Mali, and the Democratic Republic of the Congo. Isolated cases spread outside the region, including to the U.S., as the Centers for Disease Control and Prevention and other organizations worked to contain the virus. Health authorities began testing experimental Ebola vaccines in Africa as the outbreak started to wind down.

Despite a lull in 2015 and 2016, Ebola reemerged in 2017 with a relatively small outbreak in the Democratic Republic of the Congo, claiming 4 lives. Cases surged again in 2018, however, with two outbreaks in the Democratic Republic of the Congo, accounting for more than 3,500 cases and an estimated 2,320 deaths.

The year 2020 saw 55 more deaths in the Democratic Republic of the Congo, with another 27 deaths across the Democratic Republic of the Congo and Guinea in 2021. The year 2022 saw a resurgence in cases across two countries, with 6 deaths reported in the Democratic Republic of the Congo and 55 in Uganda. The outbreak in Uganda was declared over on January 11, 2023.