Lab week 1 pt 2

How does infections occur?

When germs enter body, increases in number and causes damage to host

All infections do not equal disease

1. Source (place where germs live)

2. Susceptible person

3. Transmission

Portal of entry

to cause disease the infectious agent must have a way ti get into your body

Common ones:

• digestive system

• respiratory system

Virulence

ability of a microbe to establish itself in the host and cause damage

• environmental factors

• virulence factors

Virulence factors

any characteristic or structure of a microbe that contributes to the disease state

most pathogens have adapted to specific portal of entry

• exoenzymes

• toxins

• blocked phagocytic response

Environmental factors

temperature (cold, room, hot)

air quality (moist, dry)

surface types (soft, hard)

Factors that increase susceptibility of host:

Age of person (infancy, old age)

genetic defects in immunity

acquired defects in immunity (AIDS)

surgery or organ transplants

disease: cancer, diabetes

chemotherapy/ immunosuppressive drugs

Stress (physical or mental)

other infections

How are germs transmitted?

Direct contact Transmission

1. Direct causual contact transmission

• Person to person

2. Direct intimate contact

• Body fluids

  • Sex, transfusions, organ transplants

  • Mother to infant

3. Indirect transmission

• Air Droplet spread (sneeze)

  • Food and water

3a. Indirect transmission

• vectors (mosquito biting)

4, Indirect contact transmission

• Formites