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What is Ebola virus? WHO declares emergency amid DR Congo-Uganda outbreak

Ebola outbreak has triggered a global health concern as WHO monitors rising suspected cases and deaths reported in Congo and Uganda.

There have been more than 500 suspected cases and 131 deaths recorded across the DR Congo and Uganda. (AP Photo)

5 min readMay 19, 2026 09:16 PM IST First published on: May 19, 2026 at 08:48 PM IST

The World Health Organisation (WHO) has declared the Ebola virus a public health emergency of international concern amid more than 500 suspected cases and more than 130 suspected deaths across the Democratic Republic of Congo (DRC) and Uganda.

An epidemic of Ebola disease caused by the Bundibugyo virus broke out across these two countries, triggering a public health emergency of international concern on May 17.

Also Read | At least 131 dead in Ebola outbreak in DR Congo, official says

Jean-Jacques Muyembe, director of Congo’s National Institute for Biomedical Research, told Reuters that Butembo, a city home to hundreds of thousands of people in North Kivu province, has recorded its first two confirmed cases of the disease on Monday.

According to Associated Press, Congo’s health minister, Samuel Roger Kamba, said investigations were underway to determine whether the deaths and 513 suspected cases were actually linked to the disease.

What is Ebola disease?

According to the WHO, Ebola disease is a rare but extremely serious illness in humans, often fatal. It is caused by viruses belonging to the Orthoebola virus genus within the filoviridae family.

Also Read | WHO concerned about speed and spread of Ebola: How prepared is India at airports?

Scientists have identified six species of Orthoebola viruses so far, with three of them known to trigger large outbreaks. They are-

Ebola virus (EBOV), which causes Ebola virus disease (EVD)
Sudan virus (SUDV) causes Sudan virus disease (SVD)
Bundibugyo virus (BDBV), which causes Bundibugyo virus disease (BVD)

History

The first recorded Ebola outbreaks occurred in 1976. One emerged in Nzara, in present-day South Sudan, where the Sudan virus disease was identified. The other was reported in Yambuku, in present-day Democratic Republic of the Congo, and was caused by the Ebola virus. Between 2014 and 2016, the region witnessed the largest Ebola outbreak in history, severely affecting parts of Central and West Africa.

How is the virus spread?

Fruit bats from the Pteropodidae family are believed to be the natural hosts of the Orthoebola virus. According to the WHO, the virus can enter the human population when people come into close contact with the blood, bodily fluids or organs of infected animals such as fruit bats, chimpanzees, gorillas, monkeys, forest antelope or porcupines found sick or dead in the rainforest.

It is also said the virus can spread from one person to another through direct contact with the blood or bodily fluids of someone who is sick with or has died from Ebola disease. Also spread through contact with objects or surfaces contaminated with bodily fluids such as blood, faeces, or vomit from an infected or deceased person.

Also, if any person comes in contact with a dead body can also be infected with the Ebola disease.

Possible symptoms

From the start of the symptoms, it varies from two to 21 days.

Detected symptoms can go from as basic as fever, fatigue, malaise, muscle pain, headache and sore throat, which are further followed by vomiting, diarrhoea, abdominal pain, rash and can show symptoms of impaired kidney and liver functions as noted by the organisation.

Some patients may even develop both internal and external bleeding, which can include blood in vomit and stools, as well as bleeding from the nose, gums and vagina. Bleeding at the sites where needles have been inserted into the skin may also occur in some cases. Hence, people must look out for such occurrences.

In the central nervous system, it can result in confusion, irritability and aggression.

The prevention criteria

According to the WHO, community engagement plays a central role in bringing any Ebola outbreak under control. Managing an outbreak requires a combination of approaches, including proper clinical care, surveillance and contact tracing, along with laboratory services and strict infection prevention measures in health facilities. Safe and dignified burials, vaccination where applicable and active community outreach are also essential parts of an effective response.

HEALTH — EXPLAINER

Ebola explained: What the Bundibugyo outbreak is, and why there's no vaccine for it

The WHO has declared a public health emergency over an Ebola outbreak in DR Congo and Uganda. Here is what the disease is, how it spreads, its symptoms, and where the response stands.

1What is Ebola? 2How it spreads 3Symptoms 4This outbreak

Step 1 of 4 — What is Ebola?

THE DISEASE

A rare but often fatal illness

Ebola disease is a rare but extremely serious illness in humans, often fatal. It is caused by viruses in the Orthoebola virus genus, part of the filoviridae family. Scientists have identified six species so far; three are known to trigger large outbreaks.

EBOV

Ebola virus (EBOV)

Causes Ebola virus disease (EVD). First recorded in 1976 in Yambuku, in present-day DR Congo.

SUDV

Sudan virus (SUDV)

Causes Sudan virus disease (SVD). Also first recorded in 1976, in Nzara, in present-day South Sudan.

BDBV

Bundibugyo virus (BDBV)

Causes Bundibugyo virus disease (BVD) — the strain behind the current outbreak.

HISTORY

From 1976 to the largest outbreak on record

The first recorded Ebola outbreaks occurred in 1976 — one in Nzara (South Sudan) and one in Yambuku (DR Congo). Between 2014 and 2016, the region saw the largest Ebola outbreak in history, severely affecting parts of Central and West Africa.

Step 2 of 4 — How it spreads

ORIGIN

From wildlife to people

Fruit bats of the Pteropodidae family are believed to be the natural hosts of the virus. It can enter the human population through close contact with the blood, bodily fluids or organs of infected animals.

●

Infected animals

Contact with sick or dead fruit bats, chimpanzees, gorillas, monkeys, forest antelope or porcupines found in the rainforest.

➞

Person to person

Direct contact with the blood or bodily fluids of someone who is sick with, or has died from, Ebola disease.

■

Contaminated surfaces

Contact with objects or surfaces carrying bodily fluids such as blood, faeces or vomit from an infected or deceased person.

✖

Contact with the dead

A person who comes into contact with the body of someone who has died from Ebola can also be infected.

Step 3 of 4 — Symptoms

ONSET WINDOW

2 to 21 days from infection

The time from infection to the start of symptoms varies from two to 21 days. Symptoms typically progress in stages, as noted by the WHO.

Early symptoms

Fever, fatigue, malaise, muscle pain, headache and sore throat.

Followed by

Vomiting, diarrhoea, abdominal pain, rash, and signs of impaired kidney and liver function.

Severe cases

Internal and external bleeding — blood in vomit and stools, and bleeding from the nose, gums and other sites, including where needles have been inserted.

■

Central nervous system

Can result in confusion, irritability and aggression.

Step 4 of 4 — This outbreak

513

Suspected cases reported

131

Suspected deaths

Countries: DR Congo & Uganda

WHERE & WHEN

Emergency declared over Ituri Province outbreak

The WHO Director-General determined the Ebola disease caused by Bundibugyo virus in DR Congo and Uganda a public health emergency of international concern on May 16, announced May 17. The outbreak is centred in Ituri Province. Congo's health minister Samuel Roger Kamba said investigations were underway into whether the deaths and 513 suspected cases were linked to the disease.

THE VACCINE GAP

No approved vaccine for this strain

Most approved Ebola vaccines target the Zaire strain — not Bundibugyo or Sudan. Vaccines also take about 10 to 14 days to build a full immune response, and no vaccine is 100% effective: someone already incubating the virus before a shot can still develop Ebola, though vaccination significantly reduces the risk of severe illness and death.

Sources: World Health Organization · Reuters · Associated Press

Express InfoGenIE

Are any vaccines available?

Most approved vaccines target the Zaire ebolavirus, not the Bundibugyo or Sudan strains. Besides, vaccines require about 10 to 14 days to generate a complete immune response. Individuals exposed just before or shortly after vaccination can still develop the disease. According to the WHO, no vaccine is 100 per cent effective.

A vaccinated individual may still be infected, though the vaccine significantly reduces the risk of severe illness and death. If a person was already incubating the Ebola virus before receiving the shot, they will still develop Ebola.

(Written by Paramita Datta, who is an intern with The Indian Express)