SINGAPORE: A rare strain of the Ebola virus with no approved vaccine has triggered a public health emergency of international concern, with the World Health Organization (WHO) chief warning that he is "deeply concerned about the scale and speed" of its spread across DR Congo and Uganda.The current outbreak involves the Bundibugyo strain, named after a province in Uganda.More than 500 cases and 131 suspected deaths have been reported so far. While Ebola outbreaks have historically been contained within Africa, the scale and geographic spread of this one are prompting countries, including in Asia, to step up vigilance.
Here's what we know about Ebola and why this outbreak is drawing global attention.What is Ebola?Ebola is a severe and often fatal disease caused by the Ebola virus. It spreads through direct contact with the blood and bodily fluids of an infected person, or through contact with contaminated surfaces.In some cases, transmission can also occur through contact with infected animals and bushmeat.Symptoms typically begin suddenly, and include fever, fatigue, malaise, muscle pain and headache. As the disease progresses, patients may develop vomiting, diarrhoea, abdominal pain, unexplained bleeding and organ failure.Importantly, infected individuals are not contagious until symptoms appear. The incubation period for Ebola ranges from two to 21 days.Why is the Bundibugyo strain significant?The Bundibugyo strain is rare, with only two previous outbreaks recorded - in 2007-2008 and in 2012.It has a mortality rate of 30 to 40 per cent, much lower than the Zaire strain, which causes death in up to 90 per cent of infected people, according to a study published in 2024.However, experts said the current concern lies elsewhere. There are no approved vaccines or drugs specifically for the Bundibugyo strain. "This is the third Bundabugio Ebola virus disease outbreak ever, and it is a species that we haven't seen that much," said Dr Nahid Bhadelia, founding director of Boston University's Center on Emerging Infectious Diseases."That means we don't have as much clinical experience, but also because it hasn't been that common, there haven't been as many investments in vaccines and therapeutics."She added that even if candidate vaccines are developed, they will take time to test, approve and deploy.Why are healthcare systems under strain?DR Congo and Uganda both have high-level laboratories at the central level, said Professor Hitoshi Oshitani from Tohoku University's Graduate School of Medicine.However, establishing laboratory capacity in remote areas, and in some instances, conflict-affected areas where outbreaks are occurring, is challenging. "During the recent Ebola outbreaks, a vaccination campaign was conducted. But there are no vaccines this time," Prof Oshitani added.Early detection has been challenging. Initial tests returned negative results in some cases, partly because they were not designed to detect the Bundibugyo strain. Health officials said the outbreak may have circulated undetected for weeks before it was identified.At the same time, overlapping outbreaks of endemic diseases such as malaria and cholera have made it harder to identify Ebola cases quickly.Cuts to international aid and public health funding have also weakened surveillance and response capacity on the ground, experts said, even as fresh funding is now being mobilised."Funding for things like malaria medications, bed nets and other sanitation programmes has gone down. That means other endemic diseases, like malaria and cholera, have increased in the area," Dr Bhadelia told CNA."So, if Ebola is kind of like a needle in a haystack, and the haystack of endemic infectious diseases has gone up, it makes it harder to find the Ebola cases out of that."What does the WHO declaration mean? The WHO on May 16 declared the Ebola outbreak in Congo and Uganda an emergency of international concern.This is the agency's highest formal alarm under international health law. It is used for extraordinary outbreaks that pose a cross-border public health risk and require a coordinated international response.The designation does not signal that the current outbreak is expected to become a global pandemic, but it is intended to mobilise funding, technical support and preparedness efforts.Dr Bhadelia stressed that Ebola does not pose the same global pandemic risk as airborne viruses like COVID-19, as it requires close contact to spread.The WHO's declaration was issued partly because this is DR Congo's 17th Ebola outbreak, she noted, most of which were "handled within a matter of weeks"."The trouble with this is that everything about this outbreak so far is telling us that we aren't discovering a new outbreak, we are just surfacing more details about an outbreak that has been going on for a while, so that's the number of suspect cases and deaths that we see, but also how widespread it is currently," Dr Bhadelia said. As the Ebola virus is not easily transmitted, Prof Oshitani said the risk of a large outbreak in Asia is low, although there could be "sporadic" cases imported into Asia."If these cases are not detected quickly, secondary cases among close contacts could occur," he told CNA."However, unlike COVID-19, preventing secondary transmission of the Ebola virus is not difficult. Early detection of potential cases is key to preventing secondary transmission."How are countries responding to the outbreak?While the outbreak is concentrated in Africa, its designation as a public health emergency has triggered precautionary measures worldwide, including in Asia.Countries such as Singapore, Thailand and Indonesia have stepped up surveillance, particularly at airports and border checkpoints, to reduce the risk of imported cases.Singapore has health advisories in place at all entry points, alongside requirements for travellers to declare their health status and travel history. Suspected cases must be reported immediately, and symptomatic travellers may be subject to on-site medical assessment.Thailand and Indonesia have similarly enhanced screening and coordination with healthcare providers, even though no cases have been detected locally.The United States was among the first to announce that it was screening air passengers from outbreak-hit areas and temporarily suspending visa services, after an American medical missionary contracted Ebola in DR Congo.It also urged Americans to avoid travel to the DRC, South Sudan and Uganda, and to reconsider travel to Rwanda.Experts said such measures are effective, particularly when implemented early."One of the things that has worked really well in the past is airport screenings, particularly for patients or passengers coming from those areas on both sides, when people are boarding and when they're leaving, and that's one of the things that all the affected countries are putting into place," Dr Bhadelia said.She added that while travellers should practise good hygiene, there is no need for alarm."It's always a good idea, if you're travelling for long flights, to, of course, maintain good hygiene, wash your hands, and wear a mask, particularly if you think there might be people who might be sick around you, or if you yourself might be sick," she said."But I wouldn't do it because of Ebola, I would do it just because it's good hygiene."
