West Africa is seeing its worst Ebola outbreak since 2005. The Ebola virus has now killed more than 90 people Guinea and Liberia. And many are worried it could get worse.
What is it?
EVD is a severe acute viral illness. Outbreaks primarily occur in remote villages in Central and West Africa near rainforests.
A scientist separates blood cells from plasma cells to isolate any Ebola RNA in order to test for the virus at the European Mobile Laboratory in Gueckedou April 3, 2014. (REUTERS/Misha Hussain)
Ebola first appeared in 1976 in two simultaneous outbreaks, in Nzara, Sudan, and in Yambuku, Democratic Republic of Congo. The latter was in a village located near the Ebola River, which is where the disease gets its name.
Why the worry?
There is no vaccine, specific treatment or cure for Ebola, and up to 90% of people who contract Ebola die.
Dr. Kent Brantly wears protective gear at the case management centre on the campus of ELWA Hospital in Monrovia, Liberia in this undated handout photograph courtesy of Samaritan's Purse. (REUTERS/Samaritan's Purse/Handout via Reuters)
The problem with this outbreak, is not the numbers of victims, but the fact that the cases are so spread out. The only way to stop it is to find and isolate everyone who has come in contact with it.
How is it spread?
Transmitted through close contact with bodily fluids, such as blood, saliva, semen and sweat, of an infected person or animal.
In Africa, infection has been documented through the handling of infected chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest.
Ebola then spreads from human to human by direct contact with the blood, secretions, organs or other bodily fluids of infected people, and indirect contact with environments contaminated with such fluids.
What makes Ebola so deadly?
Infection: Ebola genome contains four genes which together prevent dendritic cells — in skin, nose, lungs and digestive system — from sending messages to trigger immune system.
Unchecked viral growth: Virus spreads to cell types throughout body by binding glycoprotein to receptors on cell surfaces.
Symptoms: Onset of illness is abrupt and is characterized by fever, headache, joint and muscle aches, sore throat, red eyes and weakness.
Cytokine storm: Immune cells get caught in endless loop, releasing extreme levels of cytokines — proteins within cells which cause inflammation — and attracting yet more immune cells.
Septic shock: Infected cells detach from blood vessels causing massive hemorrhage. Loss of blood leads to kidney and liver failure.