The availability heuristic is a mental shortcut that relies on immediate examples that come to a given person's mind when evaluating a specific topic, concept, method or decision. The availability heuristic operates on the notion that if something can be recalled, it must be important, or at least more important than alternative solutions which are not as readily recalled. Subsequently, under the availability heuristic people tend to heavily weigh their judgments toward more recent information, making new opinions biased toward that latest news.(Wikipedia)
This is one of the examples of cognitive biases studied on Behavior Economics. It happens frequently on our risk assessments, specially those in our day to day routine. We exaggerate the risks of anything related to the last tragedy in the news. It happens to terrorism acts, crazy shooters, airplane disasters, diseases (Ebola?) and many other things. Things that are present (available) in our minds tend to look as more likely to happen, skewing our risk perception.
What you should do about it?
First, keep cool under new information. Look at it under the perspective of everything else you already know, and try to use data resources such as the Verizon DBIR to make more rational decisions. The base advice is to ask yourself, "what are the chances of this happening again? how frequently do these things happen? How are the chances if this happening comparing to other threats?". All those questions and thinking in terms of probabilities will help you move into a more rational way of thinking, avoiding the impact of the availability bias.