Communicable Diseases Practice Questions

What is meant by a pathogen?

Complete the table to give the type of pathogen that causes each disease.

Disease	Type of pathogen
Measles
Rose black spot
Malaria

Name the disease affecting the rose bushes and give the type of pathogen that causes it.

Give one way this disease is spread from plant to plant.

Give two things the gardener could do to treat the disease.

The human body has non-specific defence systems that stop pathogens entering.

Complete the table to describe how each part of the body defends against pathogens.

Part of the body	How it defends against pathogens
Skin
Nose
Trachea and bronchi
Stomach

Which drug originates from foxgloves?

Tick (✓) one box.

• Aspirin
• Digitalis
• Insulin
• Penicillin

Penicillin was discovered by Alexander Fleming. Name the type of organism that penicillin was extracted from.

How are most new drugs produced today?

Name the type of pathogen that causes malaria.

Give one symptom of malaria.

Mosquitoes act as a vector in the spread of malaria. Describe two ways the spread of malaria can be controlled.

Give two symptoms of measles.

Describe how the measles virus is spread from one person to another.

Explain why a child infected with the measles virus feels ill.

Name the type of pathogen that causes gonorrhoea.

For many years gonorrhoea was easily treated with penicillin. Penicillin no longer cures many patients with gonorrhoea.

Explain why.

Other than treating infected people with antibiotics, describe one way the spread of gonorrhoea can be controlled. Explain how this works.

Explain why the customers had these symptoms.

Describe three things the café staff should do to reduce the risk of spreading Salmonella to customers.

In the UK, poultry are vaccinated against Salmonella. Suggest how this reduces the number of cases of Salmonella food poisoning in people.

Describe three ways in which white blood cells defend the body against pathogens.

A child catches chickenpox. She is very unlikely to catch chickenpox again.

Explain why.

Describe the relationship shown in Table 1.

Calculate the percentage decrease in the number of cases of measles per 100 000 people between 2000 and 2015.

Explain how vaccinating a large proportion of the population reduces the spread of measles, even to people who have not been vaccinated.

Explain why antibiotics would not help this patient.

Explain how taking a painkiller will help the man, and why it will not cure him.

A different patient has a bacterial infection. Explain why the doctor must choose a specific antibiotic for this patient.

Describe how the leaves of a plant infected with TMV would look different from the leaves of a healthy plant.

Explain why plants infected with TMV grow more slowly than healthy plants.

TMV is spread by direct contact between plants and on the hands and tools of workers. Suggest two things the grower could do to stop TMV spreading to his other greenhouses.

Describe how DX-12 would be tested in preclinical testing, before it is given to any humans.

In the first clinical trial, healthy volunteers were given very low doses of DX-12. Explain why.

In a later trial, patients with the joint disease were put into three groups. Table 2 shows the results after 12 weeks.

Table 2

Group	Treatment given	Number of patients	Mean reduction in pain score (arbitrary units)
A	10 mg DX-12 each day	200	1.8
B	20 mg DX-12 each day	200	3.6
C	Placebo each day	200	1.7

What conclusions can be drawn from Table 2 about the effectiveness of DX-12? Use data from the table in your answer.

The trial was double blind and the results were peer reviewed before publication. Explain the purpose of each of these.

Use Figure 1 to describe two differences between the antibody response after the second injection and the antibody response after the first injection.

Explain, in terms of the immune system, why the response to the second injection is different from the response to the first injection.

Some months later the person is infected by the live pathogen but does not become ill. Explain why.

Calculate the percentage of samples that were resistant to the antibiotic in 2019.

Explain why the pattern shown in Table 3 is of great concern to doctors.

Antibiotics cannot be used to treat viral diseases. Explain why it is difficult to develop drugs that kill viruses.