Ebola is spread by direct contact with blood and bodily fluids, including but not limited to: urine, saliva, sweat, feces, vomit, breast milk, and semen. Also, not all these bodily fluids are as potent as others. For example, while blood and feces are usually quite abundant with the virus, other fluids such as saliva and sweat are much less likely to carry the virus. To become infected, these fluids must enter your body through either broken skin or through a mucous membrane, such as those found in the eyes, nose, or mouth.
When inside the body the virus fuses with tissue cells, invades them and releases its genetic content into the cell.
This is similar to many viruses wherein the viral RNA uses the host cells to generate copies of itself.
The genetic material takes over the cell machinery to replicate itself; new copies of the virus are formed, released into the system and dispersed. This also causes the cells to explode, sending infectious particles flying
Ebola then overpowers the immune system; the very cells that are meant to fight infection are used as carriers to spread infection to other body parts, including liver, spleen, kidneys and brain.
The virus attacks almost every organ and tissue in the human body.
The cell explosions caused by the virus lead to an overwhelming inflammatory reaction.
This is what causes sudden flu like symptoms that are the first signs of Ebola.
Vaccine development is facing a crisis for three reasons: the complexity of the most challenging targets, which necessitates substantial investment of capital and human expertise; the diminishing numbers of vaccine manufacturers able to devote the necessary resources to research, development, and production; and the prevailing business model, which prioritizes the development of vaccines with a large market potential.Read more:http://www.nejm.org/doi/full/10.1056/NEJMp1506820