The smart way to improve grades

Comprehensive & curriculum aligned

Try an activity or get started for free

Describe Communicable Diseases

Worksheet Overview

QUESTION 1 of 10

image of smartphone

 

 

Did you know that a smartphone has more than 9,000 times more germs than a toilet seat?! Gross!

So what are germs? Germs often are referred to as microorganisms. Microorganisms are just that - organisms that are microscopic. Most microorganisms are harmless, however, some aren’t. Organisms that cause infectious diseases are called pathogens. There are different types of pathogens: bacteria, fungi, viruses and protists.

 

Image of bacteria, virus and fungi

 

 

Some diseases are communicable - they can be spread from organism to organism. Different pathogens spread in different ways. Some spread through direct contact, such as in bodily fluids (like blood) or through sex. Other pathogens spread through water or air, or in food.

Pathogens cause illness in three main ways:

 

Toxins: Toxins are harmful substances produced by the pathogen that poison the body’s tissues and enzymes. This makes us feel ill.

Reproduction:  Bacteria and viruses may reproduce inside the body. A rise in the number of pathogens can damage a cell, even causing it to burst. Some pathogens hijack resources that the cell needs to be able to survive.

Immune response: Sites of infection often become swollen, sore and hot as a result of increased blood flow, often making us feel rotten.

Let’s take a look at these disease-causing pathogens in more detail!

 

 Viruses

Viruses are the smallest pathogens. The genetic material of a virus is injected into the host cell. It then takes over the host cell by copying its DNA hundreds and thousands of times. The host cells eventually burst.

Some examples of viruses are measles, HIV and tobacco mosaic virus (TMV). Let's explore these further:

 

Name

Measles

 HIV

Tobacco mosaic virus (TMV)

Description

 Measles can cause complications, especially in young children which is why they are often vaccinated against it.

 

 

HIV stands for human immunodeficiency virus.

HIV sufferers might not know they are infected as symptoms may pass. However, the virus can cause the immune system to become so damaged that it can’t deal with other infections - this is called AIDS.

Tobacco mosaic virus (TMV) affects many species of plants, for example tobacco, tomato, peppers.

 It affects chloroplasts and causes a discolouration on leaves of plants which will affect the growth of the plant.

 

  measles rash      HIV virus       A tobacco plant

Symptoms

Fever, skin rash, cold-like symptoms

Flu-like illness

Discolouration on leaves of plants

Spreads

Inhalation of droplets from sneezes and coughs

Through bodily fluids like blood, often when drug users share needles or by sexual contact

Spreads through direct contact and contaminated seeds

 

 

Bacteria

 

Image of bacteria

 

 Bacteria are larger than viruses. Bacteria replicate and divide very rapidly, allowing them to spread quickly.

 

Name

Salmonella

Gonorrhoea

Crown gall disease

Description

Salmonella causes food poisoning.

Taking antibiotics or using contraception such as condoms during sexual contact can prevent spreading.

Infects plants and fruits, such as grapes, nuts

Symptoms

Abdominal cramps, vomiting and diarrhoea

Causes a burning pain when urinating, thick discharge from the vagina or penis.

Causes galls or swollen tissues to grow on the plant stems or roots, preventing growth.

Spreads

 Bacteria in food or food prepared in unhygienic conditions

Sexually transmitted disease (STD) caused by a bacterium

Contaminated soil, water and farming tools

 

 

 

Fungi

Fungi come in different shapes and sizes. Some are microscopic, whereas others are quite large. Fungi have lots of uses in industry.

 

Name Rose black spot Barley powdery mildew
 Description

Image of roses

 

 Caused by a fungus which infects roses. Affects the growth of the plant as photosynthesis is reduced.

Image of barley fungus

 

Affects barley crops and the fungus can multiply quickly.

Symptoms

 

Purple or blacks spots develop on leaves, which turn yellow

 

Yellow spots, white fluffy growth on leaves and stems 

Spreads

Air or water, as well as through direct contact by gardeners

 

Fungal spores are spread in the air by the wind. 

 

 

Protists

Protists are usually microscopic and vary greatly from one another.

 

Name Malaria

Description

Malaria is spread by mosquitos which carry the plasmodium protist. Mosquitos suck blood containing the protists from an infected person. 

Infection can only be prevented by stopping individuals from being bitten. People sleep under mosquito nets and wear insect repellent to avoid bites. 

 Image of mosquito

 

Symptoms

 

 Fever, sweats and chills, headaches, vomiting and diarrhoea

Spreads

They pass the protist to other people they suck blood from. The mosquitos do not become ill and are called 'vectors' because they transmit the disease.

 

In the following activity, you will look at how pathogens such as viruses, bacteria, fungi and protists cause a variety of diseases. 

Kate has a cold. The doctor says a pathogen has made her sick. 

 

What is meant by a pathogen?

 

Image of bacteria, virus and fungi

A disease-causing microorganism

Germs

A disease

Pathogens can cause disease and illness.

 

What are the different types of pathogens? 

Bacteria

Viruses

Microorganisms

Protists

Fungi

Pathogens can cause disease.

 

How might pathogens spread?

 

Image of bacteria, virus and fungi

Column A

Column B

Direct contact
Tobacco mosaic virus
Eating contaminated food
Salmonella
Sharing bodily fluids
HIV
From the air
Measles

When a virus enters an organism, it will often take over the host's cells.

 

Describe how viruses grow in number in an organism.

 

Image of HIV virus attacking cells

Column A

Column B

The virus's genetic material is...
...injected into the host cell
The virus takes over the host cell by replicating....
...its DNA hundreds and thousands of times

Measles is a disease caused by a virus.

 

What are some of the symptoms of measles?

 

Image of measles rash

 

Fever

Discharge

Skin rash

Black spots on leaves

A symptom of salmonella food poisoning is vomiting.

 

How might salmonella spread?

 

Image of food

Salmonella bacteria found in food or prepared in unhygienic conditions

Salmonella can spread through the air

Salmonella can spread through bodily fluids

Malaria is a serious disease that causes many symptoms such as fever and vomiting.

 

Describe how malaria spreads.

 

Image of mosquito

Column A

Column B

Malaria is spread by...
...people they suck blood from
Mosquitos suck blood containing...
...the protists from an infected person
The protists get passed to other...
...mosquitos which carry the plasmodium protist
The mosquitos do not become ill and are called...
...vectors because they transmit the disease

Match the different diseases with the type of pathogen that causes it. 

John, the farmer is growing tobacco plants. Most of his plants are healthy but he's noticed that some are discoloured and have patches on their leaves.

 

What is the name of the pathogen that has infected some of John's plants? 

 

Image of a tobacco plant

 

How can malaria be prevented?

  • Question 1

Kate has a cold. The doctor says a pathogen has made her sick. 

 

What is meant by a pathogen?

 

Image of bacteria, virus and fungi

CORRECT ANSWER
A disease-causing microorganism
EDDIE SAYS
Did this first question confuse you a little? Germs are types of pathogens and a disease is caused by a pathogen, but the correct answer is the first option. Pathogens specifically refer to microorganisms that will cause disease or illness.
  • Question 2

Pathogens can cause disease and illness.

 

What are the different types of pathogens? 

CORRECT ANSWER
Bacteria
Viruses
Protists
Fungi
EDDIE SAYS
Were you tempted to tick them all?! Microorganism would have been wrong though! Bacteria, viruses and protists are all microorganisms, but you needed to be more specific here and give the names of pathogens. Many fungi are microscopic but lots aren't, like the mushrooms you eat! So, you should have ticked four options - bacteria, viruses, protists and fungi.
  • Question 3

Pathogens can cause disease.

 

How might pathogens spread?

 

Image of bacteria, virus and fungi

CORRECT ANSWER

Column A

Column B

Direct contact
Tobacco mosaic virus
Eating contaminated food
Salmonella
Sharing bodily fluids
HIV
From the air
Measles
EDDIE SAYS
Pathogens that can spread and cause illness are called communicable diseases. That means you can catch these diseases from others. The question above lists four different ways that pathogens can spread, but there are others too, such as in water or in the blood.
  • Question 4

When a virus enters an organism, it will often take over the host's cells.

 

Describe how viruses grow in number in an organism.

 

Image of HIV virus attacking cells

CORRECT ANSWER

Column A

Column B

The virus's genetic material is.....
...injected into the host cell
The virus takes over the host cel...
...its DNA hundreds and thousands...
EDDIE SAYS
Viruses are clever in that they use host cells' resources to grow in number! Without a host, they would be unable to replicate. This is why most viruses don't survive long outside a living host.
  • Question 5

Measles is a disease caused by a virus.

 

What are some of the symptoms of measles?

 

Image of measles rash

 

CORRECT ANSWER
Fever
Skin rash
EDDIE SAYS
Hopefully, you weren't tempted to tick the final option! Measles is a human disease, not a plant related one! Measles can be very dangerous for young children, which is often why they are vaccinated at a young age.
  • Question 6

A symptom of salmonella food poisoning is vomiting.

 

How might salmonella spread?

 

Image of food

CORRECT ANSWER
Salmonella bacteria found in food or prepared in unhygienic conditions
EDDIE SAYS
Salmonella food poisoning is caused by bacteria found in food. Often, cooking food thoroughly will destroy the bacteria. However, food that's been under cooked may have salmonella bacteria still lingering in it. It's this bacteria that can cause food poisoning.
  • Question 7

Malaria is a serious disease that causes many symptoms such as fever and vomiting.

 

Describe how malaria spreads.

 

Image of mosquito

CORRECT ANSWER

Column A

Column B

Malaria is spread by...
...mosquitos which carry the plas...
Mosquitos suck blood containing.....
...the protists from an infected ...
The protists get passed to other....
...people they suck blood from
The mosquitos do not become ill a...
...vectors because they transmit ...
EDDIE SAYS
How did you do with all that matching? Without mosquitos, malaria would be unable to spread. A mosquito is a vector, which means it carries the protist from one host to another.
  • Question 8

Match the different diseases with the type of pathogen that causes it. 

CORRECT ANSWER
EDDIE SAYS
These are the key diseases you are likely to be asked about in exams, so it's worth remembering which pathogen causes each disease! Why not check back to the Introduction if you're not too sure about these and then have a second go at this question. Well done - you've completed this activity now.
  • Question 9

John, the farmer is growing tobacco plants. Most of his plants are healthy but he's noticed that some are discoloured and have patches on their leaves.

 

What is the name of the pathogen that has infected some of John's plants? 

 

Image of a tobacco plant

 

CORRECT ANSWER
Tobacco mosaic virus
TMV
EDDIE SAYS
Tobacco mosaic virus spreads when infected leaves rub against healthy leaves, so John needs to be careful, otherwise the virus will spread throughout his whole crop.
  • Question 10

How can malaria be prevented?

CORRECT ANSWER
EDDIE SAYS
Did you get them all? Because there isn't a vaccine for malaria, preventing mosquito bites is the key to dealing with the disease. Many thousands of people across the wold die from this terrible disease every year, so it is a real cause for concern.
---- OR ----

Get started for free so you can track and measure your child's progress on this activity.

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started
laptop

Try an activity or get started for free