<a href=https://explorable.com/cause-and-effect>Establishing Cause and Effect</a>. Cause and effect is one of the most commonly misunderstood concepts in science and is often misused by lawyers, the media, politicians and even scientists themselves, in an attempt to add legitimacy to research.
You can't catch cancer from anyone, in any way. Cancer is not contagious. You can't catch HIV/AIDS just by touching somebody. The AIDS virus is not found in sweat. Yes, you can catch a cold, or the flu by shaking hands with someone if you then put your hands on/near a mucous membrane (eyes, nose, mouth).
Some diseases such as Parkinson's disease or multiple sclerosis cause uncontrollable shaking of hands or hand tremor as there is destruction of the nerve tissue. Stroke, head injury, excessive stress, strong emotions, physical exhaustion may also cause uncontrollable shaking of hands or hand tremor.