What is Ebola? A guide to the virus (and how we’re fighting it)

Over the last decade, we’ve seen the two largest Ebola outbreaks take place in West Africa (2014-16) and the Democratic Republic of the Congo (2018-20). With a new outbreak confirmed, global anxiety about the disease has been renewed while communities in the DRC and Uganda are being hit hard with rising caseloads, fatalities, and additional pressure on an already-fragile health system. 

In the last few years, however, advances in treatment, vaccinations, and outbreak response have improved the ability to contain the disease and save lives. Here’s what you need to know about the Ebola virus, including how it spreads, how it’s treated, and how organisations like Concern respond to outbreaks.

Ebola, also known as Ebola virus disease (EVD), is a rare but serious disease that can cause severe illness and death in humans. 

Several related viruses can cause Ebola virus disease. These viruses belong to a genus known as Orthoebolavirus, similar to how different influenza viruses belong to the same broader family. Three types of Orthoebolavirus are known to cause major outbreaks in humans: Ebola virus (also known as the Zaire virus), Sudan virus, and Bundibugyo virus.

The disease was first identified in 1976 during two simultaneous outbreaks in what are now South Sudan and the Democratic Republic of the Congo. The DRC outbreak happened near the country’s Ebola River, which is how the virus got its name.

Ebola is highly infectious, but it isn’t airborne. 

Experts suggest that fruit bats are natural hosts of the virus and that it can be passed to other animals in their ecosystem. It can then be transmitted to humans who have close contact with infected animals, including eating them. 

The disease passes from person to person through direct contact with bodily fluids from a person who is sick or has died from the disease – or by contact with surfaces that have been contaminated with bodily fluids. Caring for people sick with Ebola and burials for its victims are two of the main ways the virus spreads. 

Per the World Health Organisation, people cannot transmit the disease before they have symptoms. They remain infectious as long as the virus remains in their bloodstream. 

Early Ebola symptoms are often similar to those of the flu and may include:

• Fever
• Fatigue
• Muscle pain
• Headache
• Sore throat

As the disease progresses, symptoms can become more severe and may include vomiting, diarrhea, abdominal pain, rash, and symptoms of impaired kidney and liver function. Severe infections can lead to other life-threatening complications.

Ebola virus disease can be deadly, but survival rates have improved significantly in recent years thanks to earlier diagnosis, better supportive care, and new treatments. Patients are treated in isolation centres with what the WHO calls optimised supportive care: replenishing fluids and electrolytes, controlling symptoms, monitoring vitals, and managing possible co-infections like malaria. 

In 2022, the WHO also made strong recommendations for two monoclonal antibody treatments for the Zaire Ebolavirus: mAb114 (Ansuvimab; Ebanga) and REGN-EB3 (Inmazeb). These lab-made proteins act like human antibodies and help the immune system fight disease.

During the previous Ebola outbreak in the DRC (2018-20), a new vaccine was also piloted. The rVSV-ZEBOV vaccine (sold under the brand name Ervebo) had a 97.5% efficacy rate through a system known as “ring vaccination” – in which close contacts of infected patients are vaccinated to help stop the spread. Another two-dose regimen of the vaccines sold as Zabdeno and Mvaeba has also been recommended by the WHO.

These vaccines, however, only prevent the spread of the Zaire Ebolavirus, and not Sudan or Bundibugyo viruses, though several candidates for these strains are in different stages of development. 

The two largest Ebola outbreaks on record happened in the last decade. 

The 2014-16 West African Ebola outbreak remains the largest in history, originating in Guinea and soon spreading to Liberia, Sierra Leone, Nigeria, and Senegal and being declared a global health emergency.

In early May 2016, the WHO estimated a total of over 28,600 cases and 11,300 deaths. The outbreak officially ended on June 9 of that year. 

Concern had been working in the two countries hardest hit by the outbreak (Sierra Leone and Liberia) for decades prior to the epidemic. We were one of the first NGOs to respond to the crisis, immediately diverting existing resources to help fight the spread of the disease. Our safe and dignified burials programme in Sierra Leone was honoured at the 2015 EU Health Awards.

Beginning in August 2018, an outbreak in the eastern DRC region of Kivu spread to other parts of Central Africa through June 2020, leading to over 3,400 reported cases. Conflict in the DRC, including Kivu, furthered the spread of the disease, and hindered access for emergency response. By November of 2018, it had become the second-largest outbreak, though fortunately a spread to Uganda in 2019 was contained. 

In the DRC, Concern reached 400,000 people as part of a massive awareness campaign in the province of North Kivu, close to the outbreak’s epicentre in Goma. This helped to curb the spread, as did our efforts to support 23 health centres with prevention and control kits and training for 1,150 health workers in the area, based on our experience in Sierra Leone and Liberia.  

A new Ebola outbreak in the Democratic Republic of the Congo was announced on May 15, 2026, originating in the country’s northeastern province of Ituri. The WHO declared a public health emergency related to the outbreak, which had also been traced to Kampala, Uganda. 

As of May 25, 101 cases have been confirmed in the DRC, with 10 confirmed deaths. However, the WHO notes that “the epidemic in DRC is much larger,” with over 900 suspected cases and 119 suspected deaths. This outbreak is the rarer Bundibugyo virus, and its spread has been further complicated by the ongoing crisis in eastern DRC, as well as last year’s cuts to foreign aid. 

Ebola outbreaks can have devastating effects on communities, health systems, and local economies. Responding effectively means supporting not only patients, but also the frontline workers, families, and communities working to stop the spread of disease.