How diseases are spread Flashcards
Describe the difference between infectious and non-infectious diseases.
Infectious diseases can be spread form one person to another - they are caused by infection. Non-infectious diseases are not contagious
Suggest why typhoid is much more common in developing countries than in developed countries.
Developing and poorer countries might not have access to clean water, like developed countries have.
Suggest why threadworms are common in young children.
Their general heigene is worse.
Justify each of these measures used to reduce the spread of infection:
a) Using alcohol gel as you enter hospital wards.
b) Screening the blood given by donors before being used in transfusion.
a) The alcohol kills the majority of the bacteria on your hands.
b) Checking the blood for any signs of infection could prevent passing on possible diseases to the person receiving the transplant.
Dogs entering the UK from some countries are held in quarantine. Explain how this may reduce the spread of rabies and suggest why some people object to it
Quarantining the dogs allows time for the infection to go away and make the dog less contagious.
Explain why a cut quickly forms a scab
To prevent microbes from entering the body.
Describe the ways that the body defends against microbes trying to enter through the nose.
Mucus: Traps particles and contains an enzyme that kills some microbes.
Why are these methods called ‘the first line of defence’?
These defence methods are the first ones the microbes will face when trying to enter the body.
Explain why the number of white blood cells would increase in someone with an infection.
When microbes infect the body, white blood cell numbers increase and blood flows to the site of the infection.
Suggest why an infected cut may appear red and hot.
All of the activity going on beneath the surface of the skin may cause it to become red
Explain why is it rare to catch measles twice.
The T-cells and B-cells remember what they did last time to fight the infection, and can fight off the microbes before they have a chance to infect the body again.
Antibodies produced by the immune system recognise proteins on the surface of microbes. Suggest how the microbe that causes influenza avoids us becoming immune to it.
The influenza microbe regularly mutates, making it hard for the body to know what it’s fighting off.
Explain why it is helpful to have memory cells of both B-cells and T-cells.
You are more likely to successfully fight off the infection for a second time.
Give one reason why some people claim that viruses are not living things
They can only reproduce inside a host cell.
What was the discovery made by Robert Koch
Microbes cause disease.
