The full official name of Ebola is Ebola virus disease (EVD) or Ebola hemorrhagic fever (EHF).
EVD is a disease caused by one of five different Ebola viruses. Four of the strains can cause severe illness in both humans and animals. The fifth, Reston virus, is non-pathogenic to humans, though deadly to some animals.
The first known outbreak of the disease was recorded in 1976. It originated in Zaire (today´s Democratic Republic of the Congo). The virus got its name after the Ebola River which is thought to be the place where the first people got infected.
Since then, there have been several more outbreaks of Ebola in Africa with the death rate varying from 25% to 90%. On average, about half of the infected die.
Early signs and symptoms of Ebola (fever, sore throat, muscle pain and headaches) are the same as of other viral infections; therefore it is difficult to diagnose EVD in the early stages.
Later symptoms of Ebola follow quickly, within just a few days after the early sings. Infected person starts vomiting, having diarrhea; and livers and kidneys begin to fail. At this phase, some people also bleed both internally and externally.
Typically, the first symptoms appear 8-10 days after exposure to the virus, but the incubation period can last as long as 21 days.
Ebola is transmitted by contact with blood or other body fluids. Therefore, Ebola is not transmitted through the air like the flu (with the exception of being exposed to saliva droplets from immediate proximity). Therefore, sanitary precautions, protective clothes and sterile environment are necessary for those who are in contact with infected people.
The disease can also be deadly to some animals. It has an especially high mortality rate among primates such as chimpanzees and gorillas. It is estimated that Ebola may have resulted in the deaths of 5,000 gorillas so far.
Scientists suggest, fruit bats are the normal carriers of the virus, able to spread it without being affected. Humans can get infected by contact with the bats or even animals that have been infected by the bats.
The virus is able to survive for a few days within a body fluid and for several hours on dry objects.
The persistence of the virus is a reason why burying of the dead infected people poses a great risk to the survivors. Nearly two thirds of the cases of Ebola infections in Guinea during the 2014 outbreak are believed to have been contracted via unprotected contact with infected corpses during some Guinean burial rituals.
People who are lucky enough to be among those who recover from Ebola are not infectious any more. However, the virus may be able to persist in the semen of surviving men for up to seven weeks after the recovery.
The first Ebola outbreaks occurred in remote, rural regions in Central and Western Africa, near tropical rainforests, but the current outbreak has also affected major urban areas, putting millions of people in danger.
There are currently no licensed Ebola vaccines but several potential candidates are undergoing evaluation.
The research and testing of the vaccines has become very controversial topic because the populations of apes, on whom the test are usually carried out, are dwindling and in danger of extinction.
Ebola can be eliminated with heat. The virus dies when heated for 30 to 60 minutes at 140 °F (60°C) or boiled for 5 minutes.
Ebola can survive and spread in cold weather. In fact, low temperatures make the virus even more persistent.
It was during the current outbreak of Ebola that for the first time ever individuals outside of Africa contracted the disease. The very first of them, Teresa Romero, a 44-year-old Spanish nurse, contracted Ebola after caring for a priest who had been repatriated from West Africa. She made a full recovery.
The Centers for Disease Control and Prevention classified Ebola virus as a category A bioterrorism agent. It means Ebola has the potential to be weaponized for use in biological warfare.
Major U.S. international airports now screen passengers coming from the affected African countries for Ebola exposure. These precautions combined with strong health system and sanitary habits of American residents should make spreading the disease in the U.S. impossible.
Out of almost 4,000 victims killed by Ebola in the current outbreak, more than 200 have been healthcare worker and medical staff.
Recent medical studies suggest that one of the early signs that can distinguish Ebola from other viral diseases is hiccups.
Ebola comes from a family of viruses that is millions of years old. Fossilized virus samples have been found in fossils from Africa and China.
Doctors estimate that for every four cases of Ebola we know of, there might be up to six that we don’t.