Overview
This lecture explains the three types of contact transmission for infectious diseases: direct contact, indirect contact (fomites), and droplet transmission.
Types of Contact Transmission
- Infectious diseases can spread by contact transmission between people or through contaminated items.
- There are three types: direct contact transmission, indirect contact transmission, and droplet transmission.
Direct Contact Transmission
- Direct contact transmission occurs when a sick person physically touches a healthy person, spreading pathogens.
- Examples include kissing, holding hands, or sexual contact.
- Sexually transmitted infections are often spread by direct contact.
Indirect Contact Transmission
- Indirect contact transmission happens when pathogens are transferred via an inanimate object called a fomite.
- Fomites include door handles, towels, needles, computer keyboards, and mice.
- A person contaminates the object, and another gets infected by touching the same object.
- Sharing needles, towels, and similar objects increases the risk.
Droplet Transmission
- Droplet transmission involves pathogens carried in droplets expelled during coughing or sneezing.
- Droplets can travel about one meter from the source.
- A person can get infected by droplets landing directly on them or by touching surfaces with droplets.
- Droplet transmission is different from airborne transmission (e.g., measles), which can linger in the air longer and travel further.
Key Terms & Definitions
- Direct Contact Transmission — Disease spread by direct physical contact between individuals.
- Indirect Contact Transmission — Disease spread through inanimate objects (fomites) touched by an infected person.
- Fomite — An inanimate object capable of carrying infectious organisms and transferring them to a person.
- Droplet Transmission — Spread of disease via droplets from sneezing or coughing that travel short distances.
- Airborne Transmission — Spread of pathogens through the air over longer distances and times than droplets.
Action Items / Next Steps
- Review examples of each contact transmission type.
- Remember the distinction between droplet and airborne transmission for exams.