CAPF AC 2021 Q10: Science & Technology – Health & Diseases
Which one of the following diseases does not transmit through fine droplets coming out from mouth or nose of an infected person?
- (a) Pneumonia
- (b) COVID-19
- (c) HIV-AIDS
- (d) Tuberculosis
Answer: (c) HIV-AIDS
Explanation
Disease not spread by droplets
How to think: droplets come out when a person coughs or sneezes.
So droplet diseases are diseases of the lungs and airways.
Pneumonia, COVID-19 and tuberculosis all attack the lungs.
HIV-AIDS attacks the immune system and spreads through body fluids.
| Disease | Caused by | Spreads through |
|---|---|---|
| Pneumonia | Bacteria or virus | Droplets |
| COVID-19 | SARS-CoV-2 virus | Droplets |
| Tuberculosis | *Mycobacterium tuberculosis* (bacterium) | Droplets |
| HIV-AIDS | Human Immunodeficiency Virus | Sexual contact, infected blood, shared needles, mother to child |
HIV does not spread by: coughing, sneezing, handshakes, hugging, sharing food or mosquito bites.
Answer: (c) HIV-AIDS.
Why each option is right or wrong
- (a) Incorrect. Pneumonia is a lung infection that spreads through droplets.
- (b) Incorrect. COVID-19 spreads mainly through droplets from the mouth and nose.
- (c) CORRECT. HIV spreads through sexual contact, blood, shared needles and from mother to child.
- (d) Incorrect. Tuberculosis spreads through droplets when a patient coughs or sneezes.
Key point
Droplet (airborne) diseases: common cold, influenza, pneumonia, tuberculosis, COVID-19, measles. HIV spreads through body fluids: sexual contact, blood, needles, mother to child.
Remember
HIV spreads by body fluids, never by droplets.
Common mistakes
- Thinking HIV spreads through casual contact such as a handshake or a sneeze.
- Treating tuberculosis as a water-borne disease; it is airborne.
- Forgetting that AIDS patients often die of pneumonia or TB, yet HIV itself is not airborne.
Exam tip
Educated guess: three options are lung diseases. The odd one out, HIV-AIDS, is the answer.
Sources
- NCERT Class IX Science — Why Do We Fall Ill (means of spread)
- National AIDS Control Organisation (NACO) — HIV transmission