Thursday, November 20, 2014

Answering Some Questions on Ebola

An Ebola Virus
A good friend of mine pondered the mystery of Ebola on Facebook the other day. She asked why it was that some people were infected with the virus had people living with them, touching them, yet somehow these other people sometimes never got infected.

There is the popular case of the family that Thomas Eric Duncan, America's first Ebola patient lived with when he came to America.  Mr. Duncan came to America and lived with his host family consisting of his fiancée and her children for some time before he developed symptoms of Ebola. After he developed the Ebola symptoms, he was taken to the Presbyterian Hospital in Dallas and was prescribed antibiotics and sent back home. He again lived with his fiancée and family for approximately three days before he was rushed the second time to the emergency room, at which time his Ebola disease was well advanced. The copious diarrhea and vomiting had started while he was living with his host family and he had had ample time and opportunity to infect this family. It was learnt that he was even driven to the hospital by his fiancée.
Understanding Ebola

While in the hospital, Duncan's host family were kept isolated in the same apartment he had lived in for some days before they were eventually taken to another location and hazmat crews decontaminated their apartment. However, 21 days later, no member of the host family tested positive for Ebola while two nurses who worked with Duncan and were taking the recommended precautions got infected with the Ebola Virus Disease (EVD). The question then is why do some people who in contact with Ebola get it while others don't? I will try to provide an answer based on my own understanding of infection and try not to be too technical.

The greatest medicine ever created was not created in some lab by scientists, but exists in the bodies of living organisms. In human beings we call it the immune system, the body's natural defense system to foreign particles. The immune system is so wonderful a defense system, it is truly amazing. It is the body's natural medicine to help defend it against disease.

The human body is like a town surrounded by enemies; bacteria, viruses, parasites, fungi, artificial contaminants, etc. All these enemies are surrounding the town ready to enter and do serious harm. The town (human body) however has a standing army (the immune system) which responds to any attack by external enemies. The wonderful thing is that the army ( the immune system ) knows all the inhabitants of the town and so would not normally attack them. But any time a foreign enemy enters the town, the army sends soldiers known as antibodies to attack them. If the first soldiers are not enough more soldiers are sent until the enemy is overpowered. That is the simple explanation , now let me explain it in greater detail.

The immune system is the body's natural defense to foreign organism such as bacteria, parasites, and viruses. These foreign particles once they enter the body are known as antigens. When an antigen is found in the body the immune system is alerted. The first thing it does is to try to and understand the nature of the foreign particle and send the right antibody to attack it. How this is done is complex and beyond the scope of the Segbwema Blog, but let us just say that antibodies specific to that antigen are produced and they rush and kill the antigen. You can learn more about the immune system by reading the following link  http://www.nlm.nih.gov/medlineplus/ency/article/000821.htm

So when Ebola enters the body, antibodies are created to fight the virus. In some people the antibodies succeed in killing the virus and in others they don't. The people who do not mount sufficient immune response to the disease eventually end up dying, as there is yet no artificial medicine that can combine with the immune system to kill the virus. In other words there is still no cure.
Recognizing Ebola

Usually there are protein markers on bacteria and viruses that enable antibodies to find and attach to them and kill them. One of the reasons why Ebola is so deadly is that it has found  a way of shielding its protein markers from antibodies very effectively and therefore end up confusing the antibodies, allowing the virus to replicate rapidly and overpower the body by attacking human cells and destroying them.

There could be a lot of reasons why Eric Duncan's host family remained uninflected. It could be that they were exposed to him when his viral count was low, in the early stages of his infection. Their immune systems were therefore able to mount a rapid response to the virus before it could multiply rapidly in their systems. Living in America also could have helped, as your immune system is boosted by adequate nutrition. The two Presbyterian Hospital nurses were however exposed to Duncan when he was highly infectious, and this could be a reason why they were infected, as they were subjected to a high viral load before their bodies could mount an adequate response.

I really do not want to make this difficult to read, but just want to say that with every disease, everybody has a different response, as our immune systems are not the same. Some people have an immune system that could be compared to the U.S. Military; large and powerful. Some others have an immune system that could be compared to the Gambian army; small and insignificant, only used to scare the local  people.
Later Symptoms

People who have survived Ebola do so because their body has developed so much antibodies that they were able to kill all the Ebola cells. For the foreseeable future, these people will be resistant to Ebola. There are many others who would may actually have the virus in their system but have such a strong immune response that they may never get ill and hence never test positive.
That Food will Kill You

What is crucial is that at the moment the Ebola virus enters the body the immune system is strong enough to mount an effective response or the symptoms are caught at the early stage when there is still room for them to be managed successfully. When an infection is caught in the early stage, the person is kept hydrated and the fever managed while the body expels the virus and the immune system works to overcome it. Though Ebola is so mysterious, it is truly just like any other virus, just a bit more effective than most fending off antibodies.

(C) Sheku Sheriff
Hamline University

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