Ebola outbreak: why the WHO is so worried this time

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By Emma Wilkinson

The World Health Organization (WHO) has declared a current Ebola outbreak in the Democratic Republic of Congo (DRC) and Uganda is a “public health emergency of international concern”.

Doctors.net.uk looks at why the organisation is so worried about the virus:

How big is the outbreak?

It appears that a rare strain of Ebola has been spreading for weeks in an area of Africa where civil war, a highly mobile population and healthcare provided through a network of informal facilities makes it difficult to understand the true extent of the outbreak and keep it under control.

WHO director general Dr Tedros Adhanom Ghebreyesus warned there are currently "significant uncertainties to the true number of infected persons and geographic spread" of the outbreak.

The latest estimate is there have been 390 suspected cases and at least 100 reported deaths in Ituri Province in the DRC but only eight have been laboratory confirmed, the WHO said in an update on Monday.

Two other laboratory confirmed cases, including one death, with no apparent link to each other were reported in Kampala in Uganda.

The BBC has reported that at least six Americans have been exposed to the virus in the DRC.

The situation is far from the 28,600 people infected in West Africa in the largest outbreak in 2013 to 2016 - and health officials have said it does not yet meet the criteria of a pandemic emergency.

But the WHO is worried about unusual clusters of community deaths plus at least four deaths suggestive of viral haemorrhagic fever among healthcare workers.

This raises concerns about healthcare-associated transmission, gaps in infection prevention and control measures, and “the potential for amplification within health facilities”, WHO said.

Declaring a public health emergency of international concern means there is a risk to neighbouring countries and international effort is needed to coordinate the response, surveillance and prevention and infection control measures.

What is known about the strain of Ebola?

Ebola disease was first identified in 1976 after an outbreak in an area that is now the DRC and has been responsible for more than 40 outbreaks since.

Outbreaks start when an animal – usually a fruit bat - infects a human followed by human-human transmission which requires close contact with bodily fluids.

The current outbreak strain has been identified as Bundibugyo – one of four known Ebola strains and the most recently discovered.

Previously it has been implicated in two outbreaks in 2007 and 2017 where it had a fatality rate of 30%, compared with up to 90% of infections caused by the Zaire virus and 50% with the Sudan virus.

There are no approved vaccines or drug treatments for Bundibugyo virus disease although there are some experimental ones in development.

Another challenge is that tests for the infection do not seem to be accurate with more sophisticated laboratory techniques needed to identify that Bundibugyo was involved.

Current treatment for infected patients is early supportive care, including fluid, pain management and managing complications. Both patients in Uganda were admitted to intensive care facilities.

Symptoms manifest two to 21 days after exposure and initially feel flu-like before progressing to vomiting and diarrhoea and organs shutting down. Some patients develop internal and external bleeding.

What happens now?

Dr Anne Cori, associate professor in infectious disease modelling at Imperial College London, said the outbreak appears to have been detected very late, which is “concerning”.

Indications that the outbreak has been spreading for several weeks or even months, could make “standard control measures, such as contact tracing, considerably more difficult to implement effectively, especially in a setting which already faces other challenges such as conflict”, she explained.

The cornerstone of an Ebola response is active case finding and isolation, contact tracing, and safe burials because people are particularly infectious around the time of death

Deploying this approach is “feasible in theory” but can become very resource-intensive and challenging as soon as case numbers are large, and especially in large urban centres, highly connected areas, or areas impacted by conflict, she added.

Neighbouring countries, Rwanda and South Sudan have said they are on high alert.

But the risk to the UK remains very low, Cori stresses. There is no documented spread of Ebola outside Africa and even in the largest 2013-16 West African Ebola outbreak there were only a handful of cases exported to Europe despite almost 30,000 cases.

“These were mostly international healthcare workers repatriated after being infected,” she said.

WHO are putting in place an emergency committee to oversee the response.

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