Pathogens and infection

Question 1

what is an infectious disease

Answer 1

it is one that can be passed from one person to another.

Question 2

what is a pathogen

Answer 2

it is an organism that causes an infectious disease

Question 3

give 7 different ways in which pathogens are spread

Answer 3

a in water, including cholera bacterium
b by food, including Salmonella bacterium
c airborne (eg sneezing), including influenza virus
d by contact, including athlete’s foot fungus
e by body fluids, including HIV
f by animal vectors, including:
i housefly: dysentery bacterium
ii Anopheles mosquito: malarial protozoan

Question 4

give 3 example of physical barriers

Answer 4

1. skin forms a protective barrier.
2. mucus in breathing passages and lungs trap pathogens.
3. cilia move mucus and trapped pathogens out of lungs.

Question 5

give 2 examples of chemical barriers

Answer 5

1. hydrochloric acid in stomach kills pathogens in food and drink.
2. lysozyme enzymes in tears kill pathogens and prevent them entering the eyes.