Microbiology - Lecture 2

Reservoir

Source providic conditions for survival, multiplication & transmission for MO.

Zoonosis

From animal to human

Disease transmission

• Contact - direct, indirect, droplet

• Vehicle- water- food- air- borne

• Vectors- mechanical, biological

Sexually transmitted diseases

• Sensitive to environmental stress (drying)

• Do not survive outside the body

• Require direct intimate contact

Syphillis, Gonorrhea, Chlamydia

Indirect contact transmission

From reservoir via **fomite** - non-living object

Droplet transmission

With water drops, small distance

Vehicle transmission

• Waterborne- contaminated water. Shigella, E.coli, Norovirus, Hepatis A.

• Airborne - attached to dust, more than 1m. Staphylococci, Mycobacterium, M.bovis.

• Mechanical - on insects. Salmonella typhi.

Skin defence

**Mucus sectretion** - with chemicals & antibodies.

**Shedding**

**Immune cells in connective tissue** - dendritic cells phagocytosis

Parental entry

Injection, bites, cuts, wounds.

Defense by innate & adaptive immune system.

Adherence

**Tissue specific, species specific** - mediated by __interactions__ of macromolecules on bacteria and host receptors.