Disease Transmission

Question 1

What are pathogens?

Answer 1

Disease-causing organisms.

• Prions, Viruses, Bacteria, Fungi, Protozoa, Metazoa
• Infectious agents are generally specialized for a particular method of transmission.

Question 2

Why do pathogens transmit from one host into another?

Answer 2

Pathogens must have a way to be transmitted from one host to another to ensure their species’ survival.

Question 3

List the 5 routes of disease transmittion.

Answer 3

1. Air-borne transmission
2. Contact transmission (direct and indirect)
3. Vehicle transmission (water, milk, food etc.)
4. Vector-transmission
5. Tran placental transmission

Question 4

Air-borne transmission

Answer 4

When a person with an infection breathes, coughs or sneezes, he/she sprays out infected droplets.

• These infected droplets are carried through the air to a healthy person.
• Sometimes we also breathe (inhale) dust particles that are infected.

Spread occurs over short distances for Gram-positive pathogens and for viral infections such as chickenpox.

Question 5

(a) Cold and cough,
(b) Influenza,
(c) Measles, Small-pox, Chicken-pox.
(d) Whooping cough,
(e) Diphtheria,
(f) Tuberculosis.

Answer 5

Diseases that are spread by air.

Question 6

Air-borne spread: Cross-infection is greatest in ____________ and _____________.

Answer 6

Theatres, burn units.