A look at major Ebola outbreaks and when the disease was first identified

Health workers wearing protective suits tend to an Ebola victim kept in an isolation tent in Beni, Congo, July 13, 2019. (AP Photo/Jerome Delay, File)

CAPE TOWN, South Africa — Health authorities say there is a new Ebola outbreak in the Central African country of Congo, with more than 300 suspected cases and at least 88 deaths. Cases have also been reported in neighbouring Uganda.

The outbreak was declared a public health emergency of international concern by the World Health Organization on Sunday.

The severe disease that is often fatal was first identified in 1976 after two outbreaks in quick succession in what is now South Sudan and Congo, according to the WHO.

All the major Ebola outbreaks have been in sub-Saharan Africa, where the viruses that cause it are native. The worst have been in West and Central Africa.

Ebola disease is caused by different viruses

Ebola disease is caused by a group of viruses. Three of them are known to cause large outbreaks: Ebola virus, Sudan virus and Bundibugyo virus, the WHO says. The current outbreak is caused by the Bundibugyo virus, which is rare and has been responsible for only two previously reported outbreaks.

A family of fruit bats is believed to be the natural hosts of the viruses that cause Ebola, and other animals like apes and monkeys can also be infected, according to the WHO.

People can be infected by these animals, and the viruses can spread from person to person through contact with the body fluids like the blood, feces or vomit of an infected person, or surfaces that have been contaminated by body fluids.

Symptoms appear from two days to three weeks after exposure, though they usually emerge within about a week, according to the U.S. Centers for Disease Control and Prevention.

Illnesses begin with flu-like symptoms, including fever, aches, fatigue and sore throat. Later, patients can experience gastrointestinal problems, rashes, seizures and bleeding.

The average fatality rate for Ebola is around 50 per cent, according to the WHO, with rates varying from 25 per cent to 90 per cent in previous outbreaks.

There are approved vaccines and treatments only for the Ebola virus.

2013-2016: The worst outbreak on record

An outbreak a decade ago across several countries in West Africa is the worst on record.

There were more than 28,000 cases and more than 11,000 deaths as the highly contagious disease spread widely in Guinea, Liberia and Sierra Leone and spilled over into nearby nations. A small number of cases were also reported in the United States, the U.K., Italy and Spain linked to travellers from Africa or health workers returning home after helping with the outbreak.

The epidemic linked to the Ebola virus type was believed to have started in southeastern Guinea when a child — “patient zero” — came into contact with infected fruit bats, according to researchers.

2018-2020: Congo and Uganda

The second-biggest outbreak in history occurred soon after in Congo’s North Kivu, South Kivu and Ituri provinces, with some cases in neighboring Uganda. The latest outbreak announced Friday is also in Ituri, on the border with Uganda.

The outbreak eight years ago had more than 3,400 reported cases and more than 2,200 deaths with a fatality rate of 66 per cent, according to the CDC.

Like the 2013-2016 outbreak, it was also caused by the Ebola virus.

Congo has had more than a dozen significant previous outbreaks, including one as recent as late 2025.

2007-2008: Uganda

An outbreak of Ebola disease in 2007 in western Uganda on the border with Congo was the first reported occurrence of the Bundibugyo strain.

There were 131 reported cases and 42 deaths, according to the U.S. CDC, which said that the fatality rate for the Bundibugyo strain appeared to be lower than the others. However, there is still no specific treatment or vaccine for the Bundibugyo virus.

Uganda has also had several Ebola outbreaks.

1976: The first known outbreaks

The first known outbreak of Ebola occurred 50 years ago in towns in what was then Sudan and now part of South Sudan. Scientists believe it originated in a cotton factory where workers had contact with bats in warehouses, though the source has not been confirmed. It was caused by what later became known as the Sudan virus.

At least 151 people died and 284 cases were reported, many after sick people were taken to hospitals and spread the disease to health workers and others while it was still unknown, according to later studies.

An outbreak months later in northern Congo — which was then called Zaire — had 280 deaths and an extremely high fatality rate and first led scientists to identify the Ebola virus. That outbreak started in a remote village near the Ebola River, which the disease was named after.

The first known Ebola infection outside Africa occurred the same year when a British laboratory technician accidentally pricked himself with a needle while studying samples. He recovered.

Very few cases have been recorded outside Africa since Ebola was identified.

Gerald Imray, The Associated Press