BBS3027 2000: Infectious Diseases

Dr Garwin Sing

garwinS@qimr.edu.au

http://trishul.sci.gu.edu.au/courses/bbs3027/

Gut Mucosa

Gut Mucosa

Mucosal Epithelium

Epithelial Barriers to Microbial Infection: Physical

• Epithelial cells joined by tight junctions

• Exfoliation of surface cells

• Mucous flow by ciliated epithelia (respiratory tract)

Epithelial Barriers to Microbial Infection: Chemical

• Enzymes: Lysozyme (tears, saliva, sweat) Pepsin (stomach)

• pH: Fatty Acids/amino acids (skin)Gastric acids (stomach)

• Antimicrobial: Transferrin (mucus)

Epithelial Barriers to Microbial Infection:

Competition

• Gut Flora

Protection from Infectious Agents

• Innate Immunity Fever, interferon, neutrophils,

macrophages, NK cells

• Adaptive Immunity B cells, T cells

Congenital Infections

Viruses

Bacteria

Fungi

Parasites

Anatomy

Physiology

Immunity

Commensals

Sources of Infection: Exogenous

• InhalationCommon cold, flu, Legionnaire’s Disease, Coccidioidomycosis

• Ingestion Typhoid fever, tapeworm,cryptosporidium, Hepatitis A

• STD Gonorrhea, HIV• Wound Tetanus, Rabies• Insect Bite Malaria, Yellow Fever,

Dengue

Sources of Infection: Endogenous

• Gut e.g E coli

• Skin e.g. staphylococcus

• Tonsils

• Throat e.g streptococcus

• Blood e.g. EBV

• Lungs e.g Candida, CMV, streptococcus