Ebola By Aaron Ng

Description of Organism

The Ebola hemorrhagic fever is a deadly viral disease that contains RNA. The main feature of the virus is its glycoproteins on its outside to attach to the surface of cells. People remain infectious as long as the virus is in their blood stream.
The Ebola virus only has 7 genes in its genetic material.
The dendritic cells shown are the first targets of the Ebola virus once it slips into the body. Ebola initially disables these cells responsible for alerting the immune system to incoming threats when it first gets into the human body. This specialist characteristic allows the virus to disrupt the entire immune system.

Emergence

Fruit bats are the reservoir host of the Ebola virus, while chimpanzees and gorillas are other hosts that become infected as well. The virus was introduced into the human population through contact with blood, organs or secretions of these animals that have already been infected with Ebola.

Ebola is a relatively uncontagious disease as the only way of transmission to animals or humans is either through direct contact with bodily fluids or a bite from an infected host.

The true genetic background of this deadly virus is still unknown, however the disease has most likely mutated from one which only has spikes for bats. Similar to H5N1 (bird flu) and swine flu, this disease has small epidemics every few years before disappearing. The irregular activity of this disease suggests that Ebola was not created by combining with a naturally human disease, but rather a series of mutations of its spikes making strains be able to latch on to human cells.

The Ebola virus initially binds to a target cell's receptor using their glycoproteins on their surface. A process called macropinocytosis triggers after the virus has attached to the cell and will then be engulfed in a wave-like motion of the cell membrane. Once inside the cell, the Ebola virus then uncoats itself leaving only its RNA. The human cell is manipulated to begin creating the parts of the virus. After enough copies are made, the newly formed viruses leave the cell through budding and infect other cells.

Ebola's defence mechanism relies on its disruption of the host's immune system through disabling the dendritic cells from functioning properly and manipulating macrophages and monocytes. The prioritisation of certain cells may have been an adaptation or mutation in the virus that allows them to have a higher chance of survival once they get into a host's body.

Impact on its host

The symptoms of Ebola include fever, headache, muscle pain, organ failure unexplained haemorrhaging. They may appear from 2 to 21 days after the host is infected.
After disabling a host's dendritic cells, the virus then aims to infect macrophages and monocytes, large specialised cells which engulf cells to destroy them. The infected monocytes and macrophages tells the blood vessels and neutrophils to release fluids into the body, causing internal bleeding.
At the same time, Ebola viruses finds the liver very accessible and attack it, killing huge amounts of liver cells and causing organ failure. All the mechanisms of the immune system are failing while the virus continues to spread and infects more and more body cells. These problems cause the symptoms of Ebola by reducing blood supply to the brain and damaging organs.
The body has multiple defence mechanisms against Ebola. Unless there is an opening in the skin, Ebola cannot easily infect a healthy host. The immune system also contains macrophages and monocytes to deal with detected diseases. However, as mentioned before, these cells are unable to kill the virus as dendritic cells will not be able to tell these cells what to do. A cytokine storm occurs when the body reaches a critical stage in order to help the person survive.

Social or economic issues

Ebola was first discovered in two spontaneous outbreaks in 1976, one near the Ebola River in the Democratic Republic of Congo and the other in Nzara, South Sudan.
The most recent outbreak was in West Africa, first cases discovered in March, 2014. This was the largest and most complicated outbreak since its discovery in 1976. The disease has also spread between countries starting in Papau New Guinea and ending in USA, Nigeria and Liberia. Ebola is one of the most deadly infectious diseases, causing deaths in approximately 50-90% of the people infected.
Infected areas in West Africa
There is currently no cure, treatment or vaccine for Ebola, however it is difficult to be infected by it as you need to be in contact with an infected person's bodily fluids. Ebola should not infect many people for a few years aside from occasional epidemics. Despite its devastating fatality rate, many substantial mutations need to occur creating new subtypes that will more easily bind to human cell receptors before Ebola will be a world wide issue.
In order for to stop this deadly disease from spreading, developing countries that are prone to being infected with Ebola should be notified of its symptoms. Once someone notices the symptoms and reports it to health services, the virus can be controlled and prevented from infecting others.

Bibliography

https://www.youtube.com/watch?v=sRv19gkZ4E0

http://www.sciencemag.org/news/2014/08/what-does-ebola-actually-do

http://www.who.int/csr/disease/ebola/faq-ebola/en/

https://www.scientificamerican.com/article/how-ebola-blindsides-the-bodys-defenses/

http://www.livescience.com/47203-ebola-how-people-survive.html

http://www.who.int/mediacentre/factsheets/fs103/en/

http://www.news-medical.net/life-sciences/What-is-a-Macrophage.aspx

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