Intact skin protects us from viral infections including Ebola. An infected body fluid droplet that lands on your arm will not cause contamination. However, if you have a cut or a scratch on your arm this may present a risk. Please note that some injuries are so tiny that they are not visible to the naked eye.
If someone’s body fluids come into contact with those of a patient who is in an advanced stage of infection, the risk is much higher because the number of viruses in the blood is a lot higher.