Bats, animals and Ebola
Just how Ebola actually gets from animals or the environment and into humans is unclear. The virus probably "resides" in bats. From there it may occasionally infect humans that directly handle or eat bats. Or Ebola may infect an intermediate species, such as monkeys or gorillas (non-human primates), that eat contaminated partially-eaten fruit that bats drop. Humans may find the dead "intermediate" animal and then eat its meat. Either way, in each outbreak, the first human to be infected is called the "index case". This person can then infect others, especially in areas where hygiene, sanitation and infection control levels are low.
Outbreaks in humans
Ebola virus is contained in the blood and body fluids of infected people (vomit, diarrhoea, urine, nasal secretions, sweat, ejaculate). These fluids are contagious. If someone has contact with an infected person's body fluids, they can get Ebola. The more symptomatic a person is, the greater the risk of catching the virus from their body fluids. In addition, it is possible to become infected by touching contaminated objects (objects that have germs from an infected person on them). The germs get onto the toucher's hands, and then may accidentally be transferred into the nose, mouth or eyes, or enter the blood stream via cuts on the hands.
Clearly, family, carers, and medical staff are at high risk. Funeral practices that require touching, washing or kissing the dead body promote spread of the virus.
Once a human has been infected, an outbreak can occur if proper precautions are not taken.
The current outbreak in West Africa is being spread person to person.