An evolutionary tree ... which types are closely related to each other. The research will obviously be of interest to dog owners but it is hoped it will shed light on the causes of diseases ...

After studying infectious diseases, epidemiologists like Helen ... that would have resulted in transmission. A tree diagram is not the type of thing epidemiologists would usually draw, because ...

The UK Government has recently imposed a ban on importing foreign ash trees in order to prevent the spread of fungal disease Chalara ... its capacity to infect new types of plant host species.