Medical Mogul: Ebola Strikes

As you may have heard, there has recently been a large outbreak of the Ebola virus in four West African countries (as of today, the 10^th of August) with the virus threatening to spread further due to the high infectivity of the disease. However, without assessing the risk of the virus, which encompasses both the lethality of becoming infected and the probability that this will occur, the threat to the world (and hence whether it should be declared a global emergency) cannot be determined.

Details and Death Rates

This virus causes internal bleeding as well as bleeding outside the body by damaging liver and reticuloendothelial cells. Blood capillaries then leak fluids which causes a clotting response inside blood vessels which rapidly consumes platelets (clotting agents), thus preventing clotting elsewhere causing bleeding. Also the water loss caused by this leads to clinical shock which causes organ failure. This explains why the death rate of the Sudan Ebola virus is 60% for those who are infected. The virus, however, can also spread through bodily fluids such as sweat and so can be transferred by skin contact. This also means that infected needles can transfer the virus. The incubation stage of the disease lasts 2-21 days, after which, those who don’t show symptoms do not develop the disease.

This specific crisis has led to 1700 cases of the disease in Guinea, Liberia, Nigeria and Sierra Leone, with the BBC reporting that 930 people have died in Western Africa this year from the Ebola disease. In order to compare this figure reliably we must first analyse the total populations of these countries:

· Guinea: 11,474,383

· Liberia: 4,092,310

· Nigeria: 177,155,754

· Sierra Leone: 5,743,725

Hence the overall population of these countries is 198,466,172. As a result, the infected population represents 0.0009%. This would be normally considered small yet considering the infectivity of Ebola I estimate that the number of cases of Ebola will at least rise to 1891 (as shown on the graph for September). I estimate this due to a number of reasons. First, the Centre for Disease Control and Spread is now sending in 50 experts to help deal with the outbreak this is likely to cause a small decrease in the rate at which new infections are occurring. This means that the infected population may continue to rise. Furthermore, the virus has a short time to spread due to its high lethality. As a result, the infection rate in the past for Ebola outbreaks has been characterised by sharp declines and rises as shown in the table. Thus this may mean that when we see a sharp rise such in infections, as seen in the last month, we can suggest that a fast decline may ensue. The question this raises is “when will that be?” Consequently, due to this unpredictability, an estimated slow in the rate of infection is likely, as opposed to the exponential growth of the disease over the last few months. Even so, this may be a “false” plateau and the infection rate rises more rapidly again. Furthermore, as the infection rate rises, the probability of coming into contact with an infected person increases and so this means that the spread of the disease may become more rapid. Nevertheless, I believe that this could, at least in part, be offset by the global effort to isolate and track down contacts to prevent spread. This is because, as the disease becomes more prominent, more countries will become involved and so this increases the pressure to slow the spread.

A "Global Emergency"?

To assess whether the situation should be considered a global “emergency”, as has been proposed, more information is needed. This is because predicted figures lack meaning and cannot be a firm base to judge the severity of the situation. This is because, these estimates account for the current global effort, thus if complacency is established and healthcare levels are only maintained (not increased); the result would be that the exponential spreading of the disease may overcome this level of healthcare, hence changing the prediction. Instead the density of the infected population needs to be considered. Overall, the infected countries share a land area of 1,324,425 km² giving an infected population density of 149.85 people per km². This is important to calculate as it allows a comparison to be made to Britain, which has a population density of 263.48 people per km². This appears to suggest that these infected countries have fewer people living within the same land space which is confirmed as Liberia’s urban population is 48.2% of the total population whereas Britain’s is 79.6%. Consequently, this means that the spread of the disease would be less than in developed countries as fewer people live together in a nucleated settlement. Hence this means that the risk of infection may be less. However, this uses the assumption that population density is the only factor affecting the spread of the disease yet other factors, such as knowledge and awareness of the disease may offset this. Also due to the hostility of some areas of these infected countries, it means that people may be more concentrated in certain areas, which would reduce the validity of the population density figure.

Recently, the WHO’s director general, Margaret Chan (shown right) stated that “Ebola is a public health emergency of international concern” despite it being confined to a small area of Africa. This was because she claimed that countries affected don’t have the “capacity to manage the outbreak…on their own” and hence the collective security from illnesses is threatened. Yet, this assumes that the virus will spread if countries cannot manage the outbreak which can be challenged by stating that the virus, if spread to the USA for example, could be contained immediately and isolated. Hence, this means that the spread of the virus would be unlikely to jeopardise the health of developed regions. This, however, isn’t an excuse for inaction, the virus has already infected two American medical workers who have had to be flown back to the US for treatment. This treatment, as well as the cost of isolating, tracking then isolating and tracking, is expensive and so it is not practical nor ethical to ignore the virus and allow it to continue to spread and infect other countries causing many more to die. Therefore, as undeveloped countries such as the African nations affected do not have the resources to recognise the illness and prevent it from spreading by use of quarantining, this could be considered a global emergency. Furthermore, as these countries lack a developed health structure it also means that infected people cannot be identified and cared for efficiently as an underdeveloped structure may lead to work duplication as records and treatments are ordered twice. Whereas in other situations, people may not get access to treatment at all. Hence this means that it would be more economic for developed regions to take control and hence benefit from economies of scale. Also less people will realise the symptoms and even those who do may not be able to. This is because the dependency ration in Nigeria is over 80% with the majority of this due to children. Thus will this pressure to support families, taking time off already scarce work I would be viewed as a massive cost to these families.

Rescuing Responses

The response that the world should take is a complex issue so I will start by identifying the basic major control methods. Border control is particularly significant. A potential sufferer of the Ebola disease would have to show symptoms to be recognised and so this is a major risk to undermining the border control system. This argument assumes that border control cannot detect the disease without symptoms and do not check ‘normal’ people coming into the country. Being no expert on border control, I cannot assert that this is true, however careful planning could help to make it a reality if it isn’t already.

Another clear method of control is contact investigation. This involves tracking people with the disease and their contacts for 21 days. If they contract Ebola then health services isolate them and track their contacts for 21 days and the process is repeated. This forms core barriers to the disease spreading and, due to the incubation period of disease, can allow the infection to be caught up with if enough people are working in contact investigation. However, this is not currently the case due to infrastructural limits in terms of hospitals in the affected areas. This means that isolation is difficult and the administrative process of following contacts can be difficult and may lead to work duplication where the same contact is tracked or if a person is not tracked for the sufficient time and then gets Ebola. Nevertheless, these are key principles to tackle outbreaks and should be focused on and increased dramatically, this is the first action I would suggest.

Secondly, there is the issue of treating people with the disease and supporting measures to stop the spread, i.e. finding a cure or vaccine. A vaccine has not yet been developed and cannot be considered a realistic approach to stopping this particular outbreak. This is because in the long-term, a vaccine may have the benefit of containing a disease through herd immunity by reducing the contact of vulnerable people with the disease, yet in the short-term vaccines have to be tested for efficacy and safety and then have to enter an additional stage of distribution which can also be time consuming and not immediately impactful. Thus during this process, the virus may have spread which would add onto the time taken to control the disease. This is made worse by the fact that scientists have no distinct evidence of the natural host of Ebola, even though bats are strongly suspected. This is because the virus kills people and monkeys so fast that, evolutionary, these organisms cannot be hosts because otherwise the virus would have died out.

Any cure of the disease would likely have to tackle the genetic structure of the virus yet this is made difficult by the fact that there are many different families of the virus, such as Ebola Zaire and Ebola Sudan, which are genetically distinct. If these viruses would have shared more genes then it could be suggested that they would have inherited these shared genes from a common ancestor and so they represent a more basic function. Yet genes that are not common may have been inherited more recently and so the part they code for will tend to vary more as it has not been “fixed” by evolution. This means that it is more difficult to identify which gene we should target.

On the other hand, in recent news a “secret serum” has been created and used experimentally to treat one infected medical worker from the USA. This uses antibodies which lock onto the virus and prevent it from spreading. These antibodies are being produced from GM tobacco plants which means that treatment is also time consuming which means that it is a defensive measure against the disease as opposed to an offensive measure (i.e. it cannot realistically be offered to everyone with the disease to end the outbreak). This drug is also in its experimental stages and has passed the animal testing stage yet has not been clinically tested. Hence this means that the efficacy and safety has not been tested reliably. This also means that the drug risks being influence by the results of only a few people which cannot account for genetic variability and potential success on a large scale so the results have not been analysed to see whether they are repeatable and hence produce a dependable treatment. This danger of not enough testing is particularly the case with new drugs as the seemingly positive effects may have been in fact due to other factors that interact and so and success could be a coincidence. Alternatively, both the administering of the drug and recovery could be because that this has been used in a hospital setting so the drug is more likely to be given. Hence recovery may instead be influence by increase hygiene or rest. It’s a classic case of cause vs correlation. Finally, there are ethical issues over who should have access to the drug with one person questioning whether the people with the largest families should get the drug, or whether economic contribution is more important. It is an issue over deciding who should live and who should die which traditional ethical theories struggle to account for, as even the utilitarian argument (which would seem to argue that those who have the largest benefit in the long-run should live) may struggle to quantify benefit.

My Verdict

To conclude, I believe that the issue is not a global “emergency” as of today, but instead should be considered a grave concern that all countries have a duty to acknowledge. This is because I believe that an emergency implies that the situation represents a direct threat to a majority of countries which I believe it does not. In regards to the response then, I think that core control methods should be fully enforced and attention should not be massively diverted to “wonder drugs” such as the “secret serum”. I think this because the success of these drugs is fragile and if we rely too much on single drugs, then if these drugs cannot fully protect people or only work in a small proportion of people then the opportunity cost is grave. On the other hand, contact investigation and border control methods are tried and tested. Secondly, these basic methods use a systematic approach where the limits are known. For example, it is clear where you should stop checking contacts as this is the point when no more contacts are infected. The development of drugs however is less definite as although they are both objective, drug development has many more failures and it is difficult to test, compare and improve drugs. This means that when to stop looking for new treatments and to focus on a specific treatment is difficult to determine. Thirdly, imagine a long line of infected people. Using contact investigation with one worker may take a week. With two workers, this time is halved, with three workers, the time is split into three. On the other hand, with drug development, if you employ one worker to develop a drug and then another to develop another drug to see which is better, then one worker’s efforts will be eventually wasted. Thus, whilst both methods have diminishing returns (i.e. the more workers you have the less the next worker can add to the team), drug development suffers much greater. Hence, I believe that the WHO should focus on these basic methods yet still allow labs to develop drugs when they cannot contribute to preventing disease spread.