Question

A contagious disease is one that is
A. Spread from person to person
B. Caused by pathogen or its products
C. Caused by all bacteria
D. Transferred by Mosquitoes

Answer 1

Hint: Contagious disease can be defined as a disease which can be spread or transmitted from one person to another either by direct or indirect contact.

Complete answer:
A disease occurs when the normal ability of a cell or a tissue to perform any normal physiological function is hampered. A disease can be communicable like an Ebola infection or non-communicable like Diabetes.

Communicable diseases can be both contagious and non contagious.
1. Contagious diseases can be passed directly from one person to another by physical contact with an infected person, by contact with objects touched by them or by contact with their secretions. They can also be airborne which means that droplets expelled by a person suffering with disease are inhaled by a healthy person. Examples include common cold, the flu, COVID-19 and sexually transmitted one like HIV.
2. Non contagious diseases include Malaria and Dengue which require a vector or carrier like mosquito for their transmission.

Let us analyse the options to find the correct answer.
- Option A: According to the definition itself, a contagious disease is spread from person to person. Hence, this is the correct option.
- Option B: All kinds of infectious diseases can be caused by pathogens and its products but they may not necessarily be spread from one person to another. Hence, this is an incorrect option.
- Option C: Not all bacteria cause contagious diseases. Tetanus is a bacterial disease caused by wounds or injuries. Hence, this is an incorrect option.
- Option D: Mosquitoes are vectors which transmit a disease from an infected person to a healthy person. Such diseases that require an intermediate vector are Non-contagious diseases. Hence, this is an incorrect option.

Thus the correct option is A) Spread from person to person.

Note: Study of diseases and their symptoms is called pathology. When a person is able to transmit or spread the progeny of microorganism that infected him to someone else, he is said to be infectious.