Ebola: can we contain this killer disease?
In western countries Ebola is confined to thrillers and horror movies, but the biggest outbreak of the disease has health workers worried that the virus will get out of control
Airlift: western health workers have been flown home for treatment. Photograph: Ignacio Gil/ABC/Reuters
Threat: in Sierra Leone and other African countries, victims are being buried. Photograph: Tarik Jasarevic/WHO/Reuters
Experimental: ZMapp, a possible treatment for Ebola, is made with specially grown tobacco leaves. Photograph: Kentucky Bioprocessing/EPA
It starts with flu-like symptoms, progresses to nausea and vomiting and, in fatal cases, ends in confusion and unstoppable bleeding, internally and externally.
Ebola-virus disease has held the public imagination – and not in a good way – since it was first identified, in the mid 1970s, probably because of its gruesome symptoms and high death rate. Since then it has inspired bestselling books about future plagues, as well as Hollywood movies about killer microbes.
This summer the virus is back with a vengeance, with the biggest outbreak yet spanning four west African countries. The World Health Organisation (WHO), which has so far counted 1,711 cases and 932 deaths, says the current epidemic is beyond the national capacity of any affected country to control on its own.
For the first time the disease has come to Europe and the US, as infected aid workers and missionaries are airlifted out of Africa so they can receive the kind of treatment not available to sufferers back on the ground in impoverished Liberia, Sierra Leone and Guinea. Several leading airlines have stopped flights to the region in an effort to contain the spread of the virus.
“The fear is palpable. People are terrified of each other,” says Sr Anne Kelly, one of a number of Irish Missionary Sisters of the Holy Rosary working on literacy and land projects in the heart of the Ebola-affected area in rural Liberia. “If someone is suspected of having the disease they can be left high and dry by the side of the road.”
Kelly says Ebola first struck in her area more than three months ago; it was quickly – and briefly – contained. “It took a long time for anyone to believe this was real. At first people were saying their water was being poisoned, when what was actually happening was the spraying of chlorine and water for infection control.” Relief was short-lived, as the virus came back in a second wave. “It’s much more out of control and scattered around the place, even across the border with Sierra Leone.”
Borders in this part of west Africa are porous, she points out, with much intermarriage across frontiers. Efforts to contain the virus are hampered in some quarters by distrust of western medicine and an adherence to unsafe burial practices.
The scale of the outbreak, the first in the region, forced the closure of many hospitals and caused overcrowding in the treatment centres that remained open. The deaths of so many nurses and doctors has further exacerbated the situation. With the borders closed, the fragile local economy has gone into a slump.
Infecting citiesThe present epidemic is noteworthy not just for its scale. For the first time, Ebola, which until now was largely confined to the rainforests, has reached the cities. That’s a terrifying prospect, although as Prof Sam McConkey, head of the department of international health and tropical medicine at the Royal College of Surgeons in Ireland, points out, four cases out of a total population of 150 million in urbanised Nigeria is a tiny figure.
But with the world more mobile than it ever has been, the fact that some victims travelled on airlines before being properly diagnosed has spooked health experts and caused western countries to fret about their potential exposure to the disease.
The number of health workers killed in the present epidemic is also striking: doctors and nurses account for about 10 per cent of victims. If the professionals can’t protect themselves, what chance have ordinary people, some might be led to think. But this figure is most of all an indication of the paucity of facilities and basic equipment in the health services of west African countries.
McConkey believes the risk of Ebola spreading in Ireland is very low, principally because there are no direct flights with the affected areas. “The question for Ireland is not whether we’re at risk but how we can respond to the outbreak in west Africa when we’ve been asked for help,” he says. “It’s clear after six months that west African countries are failing to control this outbreak and they need a huge injection of money, staff and equipment. Otherwise it will continue to spread.”
McConkey attributes the failure of control measures so far to the basic dysfunction of the states in which the epidemic is spreading. “The ability to mobilise the 3,000-4,000 people that are needed to stop the disease through effective control mechanisms just isn’t there.”
Ebola first appeared in 1976 in simultaneous outbreaks in Sudan and the Democratic Republic of Congo. The origin of the virus remains unknown, but fruit bats are considered the likely host.
Wrong focus?Some have questioned the intense focus on Ebola over other long-running health challenges in Africa. Since it was identified, almost 40 years ago, the virus has killed a total of 5,000 people, yet measles killed 122,000 in 2012 alone. More sub-Saharan Africans die in a day from contagious diarrhoea than have died in the current Ebola outbreak, and tuberculosis isn’t far behind. And what about malaria, HIV and syphilis, all of which continue to ravage the region?
Dr Cillian de Gascun, a virologist and director of the National Virus Reference Laboratory at University College Dublin, reckons Ebola deserves the notoriety it attracts. The current strain of the virus kills between 70 and 90 per cent of its victims, he says, compared to 50 or 60 per cent for H5N1 (the cause of bird flu) and just 1 per cent for the 2009 influenza epidemic.
Downplaying its significance, while understandable, misses the point, he says. “Ebola is unique. The mortality rate is very high, and, in contrast to malaria or H5N1, the virus can be transmitted person to person. Also, in contrast to malaria, HIV, measles or influenza, there is no vaccine or antiviral treatment for the virus.”
The present outbreak began last December. It was the subject of an international alert by WHO in March, but it began getting coverage only in recent weeks, as it claimed its first western victims. “We always knew the local health services and infrastructure would struggle to control an outbreak of this nature, but if organisations like the WHO, the Centers for Disease Control and Prevention [in Atlanta], and Médecins Sans Frontières are present on the ground, and are still struggling, that is disconcerting,” de Gascun says. “It’s not unreasonable to say that the present number of those dead or infected may not in isolation stand out, but it’s the apparent potential of this outbreak to genuinely spread out of control that is the greatest cause for concern.”
Nonetheless, Ebola is readily containable with the right infrastructure, because patients are not typically infectious before symptoms appear, he points out. This isn’t the case with infections such as hepatitis A or influenza, which people can pass on before they’re even aware they have them.
In addition, we know how Ebola is transmitted. We can stop it being passed on by preventing exposure to infected bodily fluids or secretions – blood, vomit, semen, faeces, for example. Of course, first we have to identify those exposed to the virus so they can be isolated.
The HSE’s Health Protections Surveillance Centre, which has responsibility for monitoring the threat posed by infectious diseases such as Ebola, says it is well prepared to deal with any cases in Ireland. Its first guidance for health professionals on Ebola was written in 2002 and updated in 2012, and GPs have recently been issued with a leaflet on Ebola and other viral threats, such as Middle East respiratory syndrome coronavirus (MERS-CoV) and H7N9, another strain of avian flu.
Potentially lethal The centre’s director, Dr Darina O’Flanagan, emphasises the need to retain a sense of proportion in preparing for threats that are remote but potentially lethal. “The risk of Ebola coming here is low, but because it’s there and because the disease is so severe, you have to be prepared.”
Protocols have been developed to guide the work of medical officers liaising with sea and air ports, as well as that of paramedics who could be required to transport suspected cases. Confirmed cases or people at high risk would be treated at the National Isolation Unit at the Mater in Dublin, a 12-bed unit separate from the main hospital and equipped with specialised equipment for treating patients with highly infectious diseases.
“You can’t be complacent with new and emerging viral threats such as Ebola, and neither do you want to cry wolf. They may never reach our border, but I would much prefer to have alerted people, even if nothing happens, than not to have alerted people at all,” says Dr O’Flanagan.
Ironically, Ebola might be its own worst enemy, precisely because of its efficiency. When considering the threat posed by a virus, scientists are especially interested in its capacity to spread. Ebola has no problem jumping from person to person, but, as de Gascun points out, it hasn’t spread widely because it kills most of its victims, and quickly. “It’s not in the virus’s best interests to be so effective.” Finding a treatment – Zmapp could point the way Irish experts say a cure or effective retroviral treatment for Ebola is a long way off, but much attention has focused this week on the experimental and apparently successful treatment administered to an American doctor and a missionary after they were medevacked home to Atlanta.
The serum, ZMapp, made from tobacco leaves, appears to have greatly improvement the condition of the two aid workers, but it also stoked an ethical debate. The optics were bad enough: two white Americans receiving life-saving treatment while their patients back in Liberia were left at the mercy of a substandard healthcare system.
So why were the American pair the only people to receive this treatment? Why wasn’t the drug tested in Africa, where all cases of the disease have occurred previously? ZMapp has never been tested on humans but has shown some promise in tests on monkeys. The biotechnology company behind the drug, Mapp Pharmaceutical in San Diego, has been deluged with requests to produce more supplies but is unable to meet demand.
The US Centers for Disease Control and Prevention says it is too early know whether ZMapp is effective, as it is still in an experimental phase. Some patients infected with Ebola virus get better spontaneously or with supportive care – basically, fluids and electrolytes – it points out.
The question of access to new drugs is an age-old one, and has been played out in recent years in Ireland in relation to cancer treatments. There are good reasons why the testing and licensing processes for new drugs are lengthy and complicated, and why they must be based on the principle of informed consent. Even then, problems regularly arise with treatments that make it through the approval process.
Yet the world can look very different if you’re in the advanced stages of a potentially fatal disease. As Shakespeare wrote, “Diseases desperate grown / By desperate alliances are relieved / Or not at all.”