Which of the following diseases is capable of infecting others before its onset of illness?

Correct option is A

Ans. (a) Mumps
Sol. Mumps is a viral disease caused by the mumps virus. It is contagious even before symptoms appear, particularly in the 2 days before the onset of swelling and up to 5 days after. The virus spreads through respiratory droplets and direct contact with saliva.
Explanation of each option:
· (a) Mumps – Correct answer. Mumps can infect others before symptoms like swelling of the salivary glands become evident.
· (b) Typhoid – Incorrect. Typhoid is primarily spread through contaminated food and water, and transmission mainly occurs from symptomatic carriers.
· (c) Malaria – Incorrect. Malaria is transmitted through mosquito bites and does not spread directly from person to person before symptom onset.
· (d) Tuberculosis – Incorrect. TB is an airborne disease, but it is usually contagious only when symptoms like persistent cough develop.