By the time health officials confirmed new Ebola infections in eastern Democratic Republic of Congo last week, the total number of suspected cases meant the outbreak was already one of the largest on record.

A series of challenges and missteps delayed detection, two Congolese officials familiar with the response told Reuters, allowing the disease to spread undetected into rebel-held territory in the east and across the border to the capital of Uganda.

Local funeral practices helped the virus spread before any alarm was raised, diagnostic tests in a local laboratory were calibrated for the wrong strain of Ebola, and samples sent to Kinshasa were not stored or shipped properly, the officials said.

Experts say the resulting delays risk hobbling efforts to contain the outbreak, which the World Health Organisation (WHO) at the weekend declared a public health emergency of international concern.

“It’s just a scattered mess right now. I don’t think we have anything close to a real idea of how many cases there are,” said Craig Spencer, an emergency physician and public health professor at Brown University.

“Its going to be quite some time before you’re able to piece this together.”

Health worker was first known case

The outbreak is centred in the northeastern province of Ituri, a remote part of Congo grappling with poor health infrastructure and armed conflict.

The WHO has so far reported 80 suspected deaths, eight laboratory-confirmed cases and 246 suspected cases in Congo, though the true number may be much higher.

The first known patient developed fever, vomiting and hemorrhaging and died at a medical centre in Bunia, Ituri’s capital, on April 24, Samuel Roger Kamba, Congo’s health minister, told reporters on Saturday.

The person was a health worker, meaning there is little chance they were the first to become sick, Spencer said. The dead bodies of Ebola victims are contagious, but mourners gathered for a funeral, believing the death was caused by a mystical illness, Kamba said.

“Everyone is touching him, everyone is doing this… and that’s when the cases start to explode,” Kamba said.

Jean-Pierre Badombo, a former mayor of Mongbwalu town, told Reuters there were an estimated 60 to 80 deaths in Mongbwalu alone, with “six, seven, eight deaths per day”, prompting local officials to alert health authorities.

Botched testing and shipping of samples

The WHO has said it was informed of an unknown illness with high mortality in Mongbwalu on May 5, including four health workers who had died within four days, and dispatched a rapid response team.

Jean-Jacques Muyembe, director of Congo’s National Institute for Biomedical Research (INRB), said local health officials in Ituri began taking samples for testing in Bunia.

The laboratory there used testing cartridges specific to the Zaire strain of Ebola, which is the strain behind 15 of Congo’s previous Ebola outbreaks, including a 2018-2020 epidemic in the country’s east that killed more than 2,200 people.

But the current outbreak is caused by the Bundibugyo strain, which last surfaced in Congo in 2012 and, according to MSF, has an estimated case mortality rate of 25-40 per cent.

The Bunia laboratory lacks the genetic sequencing equipment needed to identify strains other than Zaire, Muyembe said, noting that only laboratories in Kinshasa and in the eastern city of Goma, which is under rebel control, can do that work.

After the tests in Bunia came back negative for the Zaire strain, the laboratory set the samples aside rather than escalating them, Muyembe said.

“The reflex should have been to contact Kinshasa and send them to our laboratory here for further investigation,” he said.

When the samples were finally sent to Kinshasa, the process was botched, Muyembe said.

The specimens arrived at 17 degrees Celsius (63° Fahrenheit), when they should have been kept at 4°C (39°F), he said. They were also shipped in microlitre rather than millilitre quantities, limiting the number of tests INRB could run, he said.

Funding cuts loom over response

Africa’s top public health agency finally announced the outbreak on May 15, and WHO Director-General Tedros Adhanom Ghebreyesus made his declaration of a public health emergency the following day.

To do so, he made the ruling personally, without consulting an emergency committee of experts, the first time he has done so in the history of the International Health Regulations, the global rulebook for responding to disease outbreaks. A committee is now being convened.

In internal documents seen by Reuters, the WHO has lamented “a critical four-week detection gap” between when the first known case started showing symptoms and laboratory confirmation of the outbreak, saying this “suggests a low clinical index of suspicion among healthcare providers”.

Lievin Bangali, senior health coordinator for the International Rescue Committee in Congo, said foreign aid cuts affecting Congo could be partly to blame.

Years of under-investment and recent funding cuts have severely weakened health services across eastern DRC, including critical disease surveillance systems that are essential for detecting and containing outbreaks early,” Bangali said.

The cuts also pose challenges as officials race to make up for lost time.

“Certain activities previously received budgetary support from donors, notably the provision of PPE kits to healthcare facilities,” Bangali said.

“Today, Ituri serves as a case in point, with virtually no PPE kits available.”