The Facts About Ebola - Dr Ed Wright
13 October 2014
The Ebola outbreak that began earlier in the year continues to spread in West Africa, with the official death toll now over 4,000. There has been a huge amount of media coverage surrounding the virus, particularly around the likelihood that it might reach the UK. We spoke to Society Champion Dr Ed Wright, a Senior Lecturer in Medical Microbiology at the University of Westminster, to get the facts about the disease.
What is the Ebola virus?
Ebola is a virus that resides in fruit bat populations. We’ve known about this virus for nearly 40 years – the first identified outbreak was in 1976, in Zaire (now The Democratic Republic of the Congo).
The Ebola virus can be passed to humans directly from bats, or via secondary hosts such as chimps, gorillas and antelope – primarily through bushmeat consumption. While the Ebola virus has previously been positively identified in Central African bats, the current outbreak suggests that the virus is in West African fruit bats too.
What are the symptoms of the disease?
In the first few days after infection, the disease presents as a fever and a rash, with symptoms very similar to flu. As the disease develops, an infected person starts vomiting and has diarrhoea. There can be blood loss in some people, but the catastrophic bleeding seen in Hollywood films is rare. Ebola targets immune cells, increases the permeability of the vascular system and impairs coagulation, which result in fluid loss from blood vessels.
When you start getting fluid and blood loss you know it is serious – this is what is responsible for the vast majority of deaths. When a patient gets to this stage they’re likely to die within days.
How is Ebola transmitted?
Ebola is a disease of contact – you need to have physical contact with the bodily fluid of an infected individual to contract the disease. This is especially true of blood, faecal matter or vomit, as the virus is present at higher levels in these fluids. If there is a break in the skin at the site of contact then it is possible to transmit the disease.
Ebola is not an airborne virus. There has been much speculation in the media as to whether it could mutate and become an airborne infection, like flu or the common cold. There is no evidence for this. Although some viruses undergo frequent mutations in their genetic code, there is no evidence from other viruses – HIV for example – that they are able to change their route of transmission.
Why is there an epidemic?
The virus is endemic in African bats and there is no way of removing it from the population. Before this year, the largest number of cases we’ve seen in a single outbreak has been in the high hundreds. These isolated outbreaks have primarily been in Central or East Africa and the populations in these areas know what to do when there have been potential cases of the disease. Until now, there’s only been one documented case in West Africa – in the Ivory Coast, in 1994 – so this outbreak appears to have rather caught the area by surprise.
The first patient in the current outbreak – the so-called ‘patient zero’ – has been traced back to December last year. The WHO wasn’t informed until March, so the virus had several months to spread into something that became difficult to contain. The lack of robust public health structures in many of the affected countries made it difficult for them to deal with the number of cases that had arisen by this point. Also, it took the international community months to respond to the outbreak. In September, Dr Joanne Liu, International President of Médecins Sans Frontières, described the international response as ‘totally, and lethally, inadequate’, a sentiment she repeated in October.
How can the epidemic be brought under control?
There is still a requirement for basic public health interventions: early diagnoses, isolation of infected individuals, proper protective equipment for medical staff and education campaigns for the local population. There also needs to be following up, or ‘contact tracing’, of people who’ve been in contact with infected individuals.
While we haven’t seen an outbreak on this scale before, these things have worked in the past and have in fact worked during this epidemic. Nigeria has been able to contain the virus and hasn’t had an Ebola case since the end of August; the country will be declared Ebola free on 20 October if this remains the case. This is partly due to the polio infections that still occur in Nigeria, which mean that the country already has health surveillance teams in place that were successfully put into action to help track Ebola when the first cases were identified. However, given the scale of this outbreak it is likely that vaccines and therapeutic drugs will be required in addition to a public health response.
What are the treatment options?
Currently, there are no approved treatments for the virus. There are some drugs and vaccines entering Phase 1 clinical trials; hopefully these will be available for frontline healthcare workers who are treating patients by early 2015. Of course, there is no guarantee that these will be effective, but the existing data is encouraging.
What are the chances of there being an outbreak in the UK?
I’d be surprised if there was an outbreak, but it would be naïve to believe that we won’t have an imported case in the future, as has happened in America. However, we’re in the fortunate position that our public health departments are well aware of the virus and they have plans in place to deal with any cases. We have excellent facilities for diagnosing, isolating and treating infected individuals, and we have a good surveillance network to follow up and quarantine anyone who’s been in contact with an infected individual.
There have been calls from some quarters to close airports – is this a good idea?
Closing ports and airports can make people’s movements unpredictable. If you keep them open, you at least have the potential to screen people for fever, for example, as they leave or enter a country. This screening can’t hurt, but the incubation period for Ebola can be up to 21 days. This timeframe gives a person unknowingly infected – who isn’t showing any symptoms – time to enter the UK or Europe. Also, it’s important that we keep the transit terminals open if we want to get aid and medical personnel to where they need to be.
Is this something we need to be afraid of?
While this is clearly a terrible and tragic disease, it’s important to remember that this outbreak remains relatively small. Millions of people are dying each year of malaria, HIV and tuberculosis, with the majority of deaths occurring in Africa. It’s right to be concerned, it’s imperative that we have a global response, but we need to keep the threat of this virus in perspective.
There are a number of papers relating to Ebola that have been published in our journals. We've collated these papers here.
Image: Dr Edward Wright, Society Champion and a Senior Lecturer at the University of Westminster..
