Transmission of Disease I & II

What does Koch’s postulates refer to?

Evidence required to establish aetiological relationships between microorganism and disease

What are the four steps of Kochs postulates?

• Microorganisms should be observed

• Isolated and grown in pure culture

• When inoculated in animals, disease must be reproduced

• Microorganisms must be recovered from diseased animal

What are four requirements for transmission of pathogens?

• Be able to leave infected host

• Survive transmission in environment

• Enter susceptible persons or animal

• Develop or multiple in newly infected host

What is the transmission chain of a pathogen?

• Agent

• Reservoir

• Exit

• Mode of transmission

• Portal of entry

• Susceptible host

What are the classifications of disease? (H,V,D,I,V,V)

• Horizontal - same generation

• Vertical - parent to offspring

• Direct - physical, touching, kissing, sex

• Indirect - air, water, food

• Vectors - rats, mosquitoes, fleas

• Virus - typhus

What is a fomite?

Object or material that are likely to carry infections such as clothes or bed (warm, anaerobic)

What are some physical defence mechanisms against pathogens entering the body?

• Tears

• Blood-brain barrier

• Gingival crevicular fluid

• Saliva

• Skin

• Blood

• Stomach acid

• Sweat

• Scabs

• Mucocillary escalator

What are two way the body responds to microorganisms?

• Immune response

• Variable response