Which one of the following is not a non-communicable disease?

A communicable disease is caused by a pathogen (bacterium, virus, parasite, or fungus) and spreads from an infected person to others through contact, air, water, food, or a vector. A non-communicable disease (NCD), by contrast, is not transmitted between people — it arises from genetic, lifestyle, metabolic, degenerative, or nutritional-deficiency causes and develops within a single individual.

Cholera is caused by the bacterium Vibrio cholerae and spreads through water or food contaminated with the bacterium, so it is a communicable disease — making it the one option here that is NOT non-communicable.

• Hypertension (persistently high blood pressure) is a lifestyle and metabolic disorder with no infectious cause, so it is non-communicable.

• Arthritis, in its most common chronic forms such as osteoarthritis and rheumatoid arthritis (joint inflammation from wear, autoimmune activity, or metabolic buildup), develops internally and does not spread between people, so it is non-communicable.

• Rickets is a bone-development disorder caused by prolonged vitamin D, calcium, or phosphate deficiency — a nutritional-deficiency disease, not an infection — so it is non-communicable.