Question

One who studies the nature and origin of diseases

Answer 1

Answer:

biologist whose interest lies primarily in the study of plants or animals can be called a naturalist, although these days it's more likely she'll be called a natural historian, a botanist, or a zoologist.

Answer 2

Answer:

Pathologist

Explanation:

You can easily get it from the word pathogen which refers to anything that causes a disease. thus one that studies nature and origin of diseases is a pathologist.