What is the child friendly explanation of the difference is between disease and illness?

Disease, like cancer, is long term… illness , like the flu, is temporary.

Disease is specific, a disease has a name, symptoms, etc. illness is simply being sick, either with an identifiable disease or just feeling sick.

Illness is what you feel, disease is what the doctor treats.

That is, illness is the symptoms from the patient’s perspective. The disease is the cause of those symptoms.

Disease is contagious; illness is anything short of injury that makes you unwell.

Disease is not necessarily contagious, no. I have Crohn’s disease. I am not contagious.

Disease is chronic and lasts forever. Illness usually goes away after a week or two.

Fwiw I’ve never actually seen any kind of official distinction between these words, I often use disease and illness interchangeably, but I assume you’re referring to the difference between chronic illness and something like the flu.

Okay, I agree with disease isn’t necessarily contagious.
@Mariah, to answer your question, yes I mean chronic illness.