4.2 Communicable Disease and Transmission

Question 1

Direct Transmission

Answer 1

• Immediate transfer of infectious agent by direct contact
• Includes droplet, biting, kissing, intercourse, sneezing, coughing, singing and talking

Examples
- Rabies
- HIV/AIDS
- Syphilis
- Gonorrhea
- Common Cold

Question 2

Indirect Transmission

Answer 2

• There is a step in between the transfer

Airborne
- Particles remain in the air for a long period of time (TB, varicella, influenza, legionellosis, measles)

Vehicle-borne
- Disease transmission occurs when non living objects (vehicles) transfer the communicable agent to a host.
- Almost any disease can transfer this way through things such as toys, handkerchiefs, soiled clothing, utensils, and surgical instruments

Vector-Borne
- Disease occurs in a living organism such as a tick or mosquito that transmits the virus
- Yellow fever, West Nile Virus, Zika, Dengue Fever (mosquito)
- Rocky mountain spotted fever, Lyme’s Disease (tick)

Question 3

DISEASE CHAIN EXAMPLE

Answer 3

• Rachel has a cold and was sneezing in her class. Katy sits next to Rachel and now begins to feel sick.

Pathogen - Cold
Reservoir - Rachel
Portal of Exit - Rachel’s nose and mouth
Transmission - Direct contact with Rachels sneezing and Katy breathing in the droplets
Portal of Entry - Katy’s nose and mouth
Infection - Viral cold infection is established in a new host, Katey