The current outbreak of Ebola in the Democratic Republic of Congo is on track to surpass the deadliest outbreak of the disease ever, the director-general of the World Health Organization (WHO) has said.

Tedros Adhanom Ghebreyesus told reporters that the 2026 outbreak, “at its current pace”, would “eclipse” that of the 2014-2016 occurrence, which killed at least 11,000 people.

The outbreak this year, declared on 15 May, has seen at least 4,300 cases and caused more than 2,000 deaths.

The WHO said on Wednesday it hoped to reverse the spread of the disease within three months but warned that this meant bringing transmission under control – not ending the outbreak entirely.

The epidemic was only officially declared in May, but it is believed the outbreak began at least three months before then, health officials said this week.

“We are chasing the virus, the virus is ahead of us,” WHO Africa director Dr Mohamed Janabi said at a news conference in the city of Bunia, near the centre of the outbreak.

He cited research showing that the virus started spreading in February and was initially misdiagnosed as malaria or typhoid.

The 2026 outbreak is caused by the rare Bundibugyo species of Ebola, which has previously caused only two known outbreaks – in 2007 and 2012.

No approved vaccine or recognised therapeutic drugs can treat this species of the virus.

Ongoing regional instability near the location of the outbreak, in the east of DR Congo, has added to challenges in controlling the spread of the disease. As a result, health workers are only reaching about 30% of cases, according to Janabi.

Ebola is a rare but deadly viral disease, with symptoms appearing within two to 21 days of infection.

Symptoms similar to the flu or malaria, including fever, headache and tiredness, can begin suddenly. As the disease progresses, vomiting and diarrhoea can develop, leading to organ failure.

The virus spreads from one person to another by contact with infected bodily fluids such as blood or vomit.

The UK’s medicines regulator, the MHRA, has given permission for the first human trials of a vaccine for Bundibugyo to go ahead.

The jab is being created by a team from the University of Oxford based on the same technology used in the Oxford-AstraZeneca Covid vaccine. Three other groups are also developing different vaccines for Bundibugyo although they have not yet entered clinical trials.

The WHO is also sponsoring a separate clinical trial in DR Congo to see whether two existing antiviral therapies can improve survival rates.