He is suffering from a chronic disease.

My younger sister is hospitalized with a childhood disease.

I'm feeling down because of May sickness.

He was diagnosed with bipolar disorder and began treatment.

He got sunstroke because he was exposed to sunlight for a long time.

Tularemia is highly infectious and can potentially infect humans as well.

My daughter caught fifth disease last week.

He missed school because of sickness.

My grandfather is suffering from Parkinson's disease.

I caught a cold, so I decided to take a sick leave.