Bacteria and Viruses

Bacteria image alt

Bacteria exist everywhere but are very small at around 1 micrometre in size (a micrometre is one thousandth of a millimetre)! Bacteria are generally made up of a single cell, but at the right temperatures they have the ability to multiply quickly.

Most bacteria are helpful, and necessary for the human body to function correctly, such as Lactobacillus and Bifidobacterium which live inside our guts and help break down our food. In fact, people have more bacteria cells in their bodies than human cells.

However, some bacteria can cause illnesses in humans, therefore it is important to make sure your home is regularly disinfected, in addition to regular cleaning. To find out more about the difference, click here.

Commonly found bacteria that can cause illness in humans

Enterococcus hirae

Enterococcus hirae


Responsible for
Wide range of infections, particularly affecting the urinary tract, abdomen, blood, wounds etc

Causes
Found almost everywhere, including soil, food, animals and faeces.

Escherichia coli (E Coli)

Escherichia coli (E Coli)


Responsible for
Sickness, severe diarrhoea and abdominal pain.

Causes
Contaminated food, not washing hands after touching animals or going to the toilet/changing nappies.

Legionella

Legionella


Responsible for
Legionnaires’ disease, Pontiac Fever, Lochgoilhead Fever

Causes
Widespread in natural water systems, found commonly in shower heads, spa pools and hot and cold water systems. Caused by breathing in water droplets containing the bacteria.

Listeria

Listeria


Responsible for
Food poisoning - fever, vomiting, diarrhoea.

Causes
Listeria can be found in soft cheeses made from unpasteurised milk, raw meat, pate, unpasteurised milk and unwashed vegetables. It can grow in the cold temperature of the fridge as well as live in food processing plants.

Pseudomonas aeruginosa

Pseudomonas aeruginosa


Responsible for
Wide range of infections, especially amongst people who are already sick.

Causes
Mainly spread within hospitals/care homes by health care workers, medical equipment or surfaces such as sinks and toilets.

Salmonella

Salmonella


Responsible for
Food poisoning - sickness and diarrhoea.

Causes
Salmonella can contaminate meat, eggs, poultry, milk and other dairy products. Pets can also carry salmonella and contact with animals or their stools (faeces) can infect humans.

Staphylococcus aureus

Staphylococcus aureus


Responsible for
From a minor boil or skin abscess to life-threatening infections like septicaemia. MRSA is a strain of bacterium which can cause severe infection.

Causes
Bacteria entering the skin or eating contaminated food. Transmitted to humans and animals from bacteria found in air, dust, sewage, water, milk or food equipment.

What is a virus image

 Viruses are also very small and are much simpler than bacteria. In order for viruses to multiply or reproduce, they need to take over a 'host' cell, such as in a plant, animal or human.

There are some viruses that are helpful to human bodies, such as those used in vaccinations, but the vast majority of them cause disease.

Examples of viruses are:

 

Commonly found viruses that can cause illness in humans

Influenza Virus H1N1

Influenza Virus H1N1


Responsible for
Flu

Causes

Rotavirus

Rotavirus


Responsible for
Sickness and diarrhoea

Causes

Rhinovirus

Rhinovirus


Responsible for
Coughs and colds

Causes

Human Herpes Virus 1

Human Herpes Virus 1


Responsible for
Chicken pox (see www.itchi.co.uk for more information) and cold sores

Causes

Respiratory Syncytial Virus (RSV)

Respiratory Syncytial Virus (RSV)


Responsible for
Infection of the lungs and breathing passages, in particular of infants.

Causes