Tuesday, October 21, 2014

The Truth About Ebola

Any time a relatively obscure topic becomes front page news overnight, people become overwhelmed with information pouring in from all sides: TV, newspapers, the Internet etc. And as usual, right along with all the credible information, folks start being inundated with conspiracy theories and people spreading misinformation or information they have misunderstood. As we have seen, this has created a kind of communal national anxiety attack. 

In the light of all that has happened, I want to take you through the basics and hopefully ease any anxiety and clear up some confusion.  



Introduction

Ebola is a hemorrhagic fever caused by an Ebola virus. There are 5 species of Ebola virus, with the most common being the Zaire ebolavirus. Ebola was first discovered in 1976 and is named after the Ebola River in the Democratic Republic of Congo (formally known as Zaire). Since 1976 there have been 27 individual outbreaks; however, 4 of them were laboratory accidents and the disease did not spread beyond the first patients.

A computer model of the virus.

The various natural outbreaks have had mortality rates ranging from 25% to 90%. The current outbreak, which began in December 2013, has a case fatality rate of 71%. There have been over 9,600 reported cases and 4,800 deaths. (The discrepancy between the reported cases/deaths and the fatality rate is that the fatality rate is based off of proven Ebola cases/deaths vs. those suspected of being Ebola.) It is very likely that in the primary affected countries, the number of cases and deaths have been under reported. This outbreak is by far the largest in history, with more cases than all the others combined. In August 2014, the World Health Organization estimated that 20,000 people are expected to contract the disease. That estimate is likely to be greatly surpassed

The current West Africa epidemic began in Guinea and then spread to Liberia, Sierra Leone, Nigeria, Senegal, Spain, and the United States. The outbreaks in Nigeria and Senegal were stopped. Liberia, with a population of 4.3 million, has the greatest number of cases, followed by Sierra Leone, and then Guinea. There's also a separate (unrelated) outbreak in the Dem. Rep. of Congo which began in August 2014 and has claimed 68 lives. 

Ebola symptoms can begin 2-3 days after exposure, all the way up to 3 weeks after, with a small number of cases not experiencing symptoms until a month after. The first symptoms are often fever followed by a sore throat, muscle pain and headaches. Further symptoms include a rash, diarrhea, nausea & vomiting, shortness of breath, swelling, confusion, bleeding from the eyes, nose, and other openings, and internal hemorrhaging. Death typically occurs 6 to 16 days after the start of symptoms. Ebola is NOT airborne. It is only spread through contact with bodily fluids like vomit, diarrhea, blood, sweat, breast milk etc. or by objects contaminated with body fluids.


Transmission

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There has been no change in the way Ebola is transmitted, but since people have been confused about its transmission through sweat or through the air from things like coughing, I’m going to explain a bit more on this. Different body fluids can contain different levels of a virus or bacteria; this has always been the case. Viral infections occur when a person is exposed to the necessary viral load (a certain number of viral particles) and the virus survives in the body, and then begins reproducing. For some diseases that can happen with a single viral particle (known as a viron), for others it requires thousands. And so, the risk of getting Ebola from sweat is less than the risk of getting it from blood. In a 2007 study of Ebola transmission from various fluid types (including sweat), saliva, stool, blood, and breast milk were most likely to contain virons; the single sweat sample did not have any viral particles. It needs to be stressed that doctors can't say "yes this happens" or "no this is impossible" unless there's real evidence to support the claim. As more and more studies are done, it's obvious that we will learn more and things may change. Until then, we can only go by what has actually been proven.   

Different viruses can also live on surfaces for different lengths of times. In the case of Ebola, once the body fluid has dried on a surface, the virus dies within hours. Ebola is a very weak organism outside of a body and cannot survive long outside of a host, and it is easily killed by chemicals like household bleach.

On the issue of airborne transmission. Airborne transmission is basically when a virus (or bacteria) can survive in the air for extended periods of time and is then picked up by other people which can then make them sick. When someone has an infection, their body contains billions (or trillions) of germs, and so when they sneeze or cough, they expel large numbers of germs into the air which can then be breathed in by another person. Respiratory droplets from sneezing & coughing are a form of bodily fluid & that has always been the case. HOWEVER, Ebola cannot survive outside of the body for long, and once those droplets dry the virus dies. Because of this, because Ebola can’t live in the air, Ebola is not an airborne disease.  Also, coughing & sneezing are not common symptoms of Ebola.

The jump to become an airborne disease takes more than a single "switch" flip, it takes multiple mutations in the right way. While Ebola could theoretically become airborne, there's no evidence that is has become airborne or is nearly there. Any disease could theoretically become airborne, but until it actually does, the only thing that exists is speculation. If people really are afraid of this, then all the more reason for us to do all we can to stop this outbreak in Africa. 

To stress the point: unless you have had physical contact with the skin, blood, vomit, stool, saliva, or other fluids of an Ebola patient, or of their corpse; or if you have had physical contact with sheets or other objects which have liquid matter on them from an Ebola patient; or if an Ebola patient has projected their fluids onto you.... then you do not have Ebola. 


Infectious vs. Contagious

I also want to try and clear up some questions about infection and contagion. Ebola is very infectious. That means that it only takes a small amount of virons to infect a person. Infection means that the virus is able to survive in the body and successfully replicate. Contagious on the other hand describes how easily a disease can spread from person to person. Ebola is highly infectious, but it is not highly contagious under normal circumstances.

The contagiousness of a disease boils down to something called the reproduction number (shown as "R0" or "R nought"). R0 is a mathematical term that tells you how contagious an infectious disease is. Specifically, it's the average number of people who catch the disease from a single sick person during an outbreak. If a disease's R0 is less than 1 an outbreak will die out, if it's greater than 1 then the outbreak is likely to grow. 


A good example to use is measles, which is one of the most contagious diseases known. Its R0 is around 18. In other words, one person with measles will infect 18 others (on average) when no one is vaccinated. On the lower end of the R0 spectrum are viruses like HIV and hepatitis C. Their R0's tend to fall somewhere between 2 and 4. They still manage to infect large numbers of people, but compared to the measles their contagiousness is relatively low (leading them to spread more slowly).

For Ebola, the virus's R0 is around 1 to 2, which less than the common flu. 

For some context: up to 50,000 Americans die from the flu each year (or 0.015% of the population), as of today 0.000001% of the American population have been diagnosed with Ebola (including those who worked in West Africa). Likewise in West Africa, Ebola hasn't reached the level of malaria or even deaths due to hunger. This isn't to suggest that Ebola is harmless, on the contrary it has the potential to kill hundreds of thousands in West Africa. But, I wanted to show that while the media may be consumed with Ebola reporting, currently the spread of the disease hasn't reached the levels of more common illnesses that kill just as many (and more) each year. 


Treatment and Prevention

Currently there is no cure for Ebola, and the only treatment is to try and keep people hydrated and comfortable until they either die or until their immune systems are able to fight it off and recover. Normally, medications take 10 years to go from an idea to an approved drug and can cost billions in R&D and government fees. In the case of severe diseases this can be sped up, but it still takes time to create enough of the drug and to make sure that it will help and not harm patients. The ZMAPP experimental vaccine given to the two American healthcare workers is still being studied, as are two other potential vaccines. It’s going to take time though before anything is approved for wide-spread use, if they’re proven effective.

The best way to protect yourself from an infected person is to be covered from head to toe in protective equipment, with no skin showing at all. There are several kinds of personal protective equipment and there are various protocols for putting them on and taking them off, and it takes practice to get it right. The most recent CDC guidelines stress that repeated practice in "donning and doffing" is required to help ensure that people don't make mistakes. 

Preventing the spread of Ebola hinges on containment. Once an infected person is found, the next step is to identify all those who may have had contact with the patient and then to narrow that list down to those who actually did have contact either directly with the patient or with their bodily fluids. Those people will then need to be monitored and isolated from others. A criticism of this protocol has been that it relies, in part, on potential patients being honest about their travel history and symptoms. As noted earlier, in the overwhelming majority of cases the first symptom is fever. While a low grade fever can be masked by things like Tylenol, higher fevers aren't so easily hidden, and once a person begins having a fever other symptoms quickly follow, and those cannot be hidden. Since people are not contagious until symptomatic, once you identify the potential patient(s) and isolate them, and follow the proven Ebola protocol which has been in place for 40 years, then transmission stops and the outbreak comes to an end. 

Since Ebola spread to the capital of Liberia, it was able to infect far more people than previous outbreaks which had happened in isolated communities. When you combine a dense population center with the poor level of medical infrastructure, the level of mistrust of modern medicine by the average person in these regions, and the level of pervasive superstition, it is easy to see how it spread so rapidly. To help understand the dreadful state of medicine in the affected countries, in Liberia for example, there is 1 doctor for every 90,000 people. In the United States, there’s 1 doctor for every 400 Americans.


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When trying to grasp all the things that have happened recently in the US, a dose of reality is always helpful. Healthcare workers are human beings and they can make mistakes, especially when stressed. It is completely unreasonable to expect that there will not be mistakes, or that somehow they’re supposed to know everything. For 38 years Ebola was an “African” disease, and a disease that was fairly easily contained. Most American healthcare workers have never given it a thought. And now that it has reached the US, we are having to educate literally millions of doctors, nurses, and other medical professionals – from the major hospitals all the way down to small walk-in clinics, on the dangers of the disease, its symptoms, and on the protocols on how to deal with potential Ebola patients. This will take time and mistakes are bound to happen. In the end, the real problems and breakdowns have been shown to come from human error. The science and protocols have all been tested in the real world and proven effective time and time again. Unfortunately, people make mistakes and do things they shouldn't (like failing to properly protect themselves, lie, or use mass transit when they've been exposed).


Travel Restrictions

The CDC and National Institutes of Health have generally been opposed to travel restrictions. Commentators, particularly those on the right, have pushed this issue and seem to be ignoring the actual reasoning the government has been giving regarding why they're opposed to travel bans. On Oct. 16, 2014, CDC director Dr. Tom Frieden and National Institute of Allergy and Infectious Diseases director Dr. Anthony Fauci testified before Congress and were grilled multiple times on the issue of preventing people from the affected countries from coming to the US as a means of stopping the spread of Ebola in America.




Having watched the testimony this is my understanding of why they don't support such a ban. NOTE: I am not saying I personally support or oppose a travel ban, I'm simply trying to explain the reasoning behind why the CDC opposes one. 


Currently, people are free to travel to the United States from the affected countries. Of the roughly 150 West Africans a day who come here, 94% enter through five specific airports. At these five airports, passengers from those countries will undergo enhanced screening procedures: having their temperature taken, asked about people they've been in contact with, checked for other symptoms, asked about where they've been and where they're going, etc. And if they have symptoms they will immediately be quarantined. Other airports and border security locations had also been given a set of guidelines as well. Should persons from the affected countries come through their facilities, those travelers would also undergo a screening process. 


However, as of Oct. 21, the government is requiring that all passengers from the affected countries now arrive at one of those five primary airports. 

The benefits of this are multiple: they know who exactly they area, where they have come from, where they are going, their contact information, the contact information of friends & family, etc. And that information can then be passed on to local hospitals and the authorities in the event that they become sick. This gives them the added benefit that if someone gets sick, they can then initiate the tracking, screening, and monitoring procedures for anyone inside the US who may have been in contact with the patient so that they can then contain a potential outbreak.


The primary criticism of this is that if we don't let them come to the US in the first place, we won't have to worry about an outbreak to begin with. 


Something to remember is that there are no direct flights from western Africa to the United States, all of these passengers have to go through other countries first. The worry about a travel ban is that while we may stop 145 visitors from coming here openly, for the other 5 people (or just 1), a ban may potentially force a frightened person to come to the US through other or illegal means. If they did indeed have Ebola, this would lead to a situation where we don't know who they are, where they came in from, who they came in contact with, or where all they may have traveled. That could mean an outbreak could occur anywhere in the country and lead to dozens, or even hundreds of other potential patients by the time the west African patient was finally located. In that case, the amount of work required to do contact tracing, monitoring people, etc. would be far more and more difficult than the work required to watch those who came here openly. 


Another problem with any travel ban is the fact that people move around. They don't necessarily have to be a Liberian citizen for example, they could be English, or French, or from Nigeria (the most populous country in Africa), or from someplace else. To effectively enforce such a ban we would necessarily have to block people from coming to America from many other countries. 


Anything we do (ban, no ban, something else) necessitates a level of risk. In the eyes of many experts, the risks of a travel ban is greater than the risk of tracking people who are moving around openly as opposed to moving around in the shadows. Of course as time goes on, things may change.



Last Thoughts

In the case of the CDC, or any governmental scientific organization, they are going to try very hard to only talk about the things that are currently known; those things shown in peer-reviewed scientific reports. Talking about theories and speculations in front of millions of people who may not fully understand the science isn't going to help anything and will only lead to more confusion. So, they’re going side step certain questions and answer others only in the context of what has actually been proven. This doesn't mean they’re hiding things. The only boogieman is the disease itself. 

It’s also very important to understand that medicine, and indeed the bulk of all sciences, are a matter of probabilities, and our understandings are subject to change when new information is learned. This is the largest outbreak ever, we are going to learn things we didn't know before because now more people have the disease. It’s also important to remember that medical terms like “airborne” have very specific definitions and those definitions may be different from what most people understand them to be. Getting caught up in fear; or listening to people who have misunderstood the facts; or mistaking an opinion for fact; all of these things serve to hamper efforts to putting an end to this outbreak. 

I also find it rather disingenuous to blame the government for the actions of free people. The nurses who contracted Ebola from Thomas Duncan were not federal employees, they were just average nurses from a hospital in Texas. While we don't exactly know how they were exposed to Ebola, it could be as simple as improperly suiting up (while the nurses may have been confident they covered themselves correctly, they could have been wrong), and there's very little anyone can do in those types of cases; of cases of honest human error. It's easy to blame the government, and there's plenty to blame them for. That said, they're not to blame every time someone somewhere does something bad. 


As of today only two people out of 315 million have contracted Ebola while in the United States. The sky is not falling. 


--Jacob Bogle, 10/21/14
Facebook.com/JacobBogle
Twitter.com/jacobbogle

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