1.1 Identify the differences between bacteria, viruses, fungi and parasites

This guide will help you answer 1.1 Identify the differences between bacteria, viruses, fungi and parasites.

You often come across microorganisms in health and social care settings. Microorganisms are living things that are too small to see with the naked eye. Some can help us, but many can cause infections and disease. Four common types are bacteria, viruses, fungi, and parasites. Each of these groups is different. Knowing their differences helps you follow the right infection control procedures and protect the people you support.

Bacteria

Bacteria are single-celled organisms. They are among the oldest forms of life and can survive in different environments. You can find bacteria in soil, water, and inside the human body.

Key Features of Bacteria

• Bacteria are living cells. They carry out all basic life processes.
• They have a simple structure with a cell wall and cell membrane.
• Most bacteria multiply through a process called binary fission, where one cell splits into two.
• Some bacteria need oxygen to live (aerobic), while others do not (anaerobic).

Shapes and Types

Bacteria come in different shapes:

• Rod-shaped (bacilli)
• Round (cocci)
• Spiral (spirilla)

There are thousands of types. Some are useful for making foods like yoghurt. Others can cause illnesses.

Effects on Health

Most bacteria are harmless. Some are even beneficial, like those in the gut that help digestion. Other bacteria can cause infections, such as:

• Tuberculosis
• Urinary tract infections
• Pneumonia

Treatment

Infections caused by bacteria are usually treated with antibiotics. However, overuse of antibiotics makes some bacteria resistant, which is a growing problem.

Viruses

Viruses are much smaller than bacteria. They are not cells and cannot live or multiply alone. A virus must enter a living host cell to survive and reproduce.

Key Features of Viruses

• Viruses are made up of genetic material (either DNA or RNA) protected by a protein coat.
• They cannot grow or carry out life processes on their own.
• Viruses take over the machinery of host cells to make hundreds of new viruses, which then leave and infect other cells.

How Viruses Spread

Viruses can spread in different ways:

• Through droplets from coughing or sneezing (like influenza)
• Through body fluids
• By contaminated food and water

Common Viral Illnesses

Viruses are responsible for many diseases, some mild and some severe, such as:

• The common cold
• Flu (influenza)
• COVID-19
• HIV/AIDS
• Chickenpox
• Hepatitis

Treatment

Antibiotics do not kill viruses. Some viral infections go away on their own, while others may be prevented with vaccines or treated with special antiviral medicines. Good hygiene and vaccination are important ways to prevent the spread of viruses.

Fungi

Fungi include yeasts, moulds, and mushrooms. Unlike bacteria and viruses, fungi are more complex. Some fungi are single cells (yeasts), but many are made of many cells (moulds).

Key Features of Fungi

• Fungi have a nucleus and other structures inside their cells, making them more complex than bacteria.
• Fungi can be seen growing as colonies in damp, warm areas.
• They reproduce by forming spores, which can spread through the air.

Where Fungi Live

Fungi are found in soil, on food, and on living and dead organisms. Most fungi feed by breaking down dead material or living as parasites.

Fungal Infections

Fungi can cause infections, especially in people with weak immune systems. Common fungal infections include:

• Athlete’s foot
• Ringworm
• Thrush (oral or vaginal candidiasis)
• Nail infections

Fungal Infections in Vulnerable People

Fungal infections are more dangerous for people with low immunity, such as those with cancer, HIV, or who have organ transplants.

Treatment

Fungal infections are treated with antifungal medicines. Good personal hygiene and keeping areas dry can help prevent fungal growth.

Parasites

A parasite is an organism that lives in or on a host (another living thing) and gets its food from or at the expense of its host. Parasites can be single-celled or multi-celled organisms.

Types of Parasites

There are several types:

• Protozoa: Single-celled organisms that can live in blood or the gut.
• Helminths: Worms such as roundworms, tapeworms, and flukes.
• Ectoparasites: Parasites that live on the surface, such as lice or scabies mites.

Key Features of Parasites

• Parasites cannot survive for long outside a host.
• They may cause harm to the host through tissue damage, stealing nutrients, or by triggering immune responses.
• Parasites often complete complex life cycles, sometimes involving more than one host.

How Parasites Spread

Parasites can spread in different ways:

• Through contaminated food and water
• By insect bites
• By direct person-to-person contact

Common Diseases Caused by Parasites

Parasite infections can range from mild to severe:

• Malaria (caused by protozoa carried by mosquitoes)
• Giardia (an intestinal infection)
• Threadworms in children
• Head lice

Treatment

Treatments depend on the type of parasite. Some may need special medicines called antiparasitics. Prevention methods include good hygiene, safe food preparation, and using insect repellent.

Comparing Bacteria, Viruses, Fungi, and Parasites

Understanding the differences between these groups is important in care settings. Each type has unique features, ways of spreading, and treatments.

Feature	Bacteria	Viruses	Fungi	Parasites
Structure	Simple cell	Not a cell	Complex cell(s)	Simple or complex
Size	Microscopic	Much smaller	Some visible	Varies (tiny to visible)
Living status	Living	Not alive	Living	Living
Treatment	Antibiotics	Antivirals/vaccine	Antifungals	Antiparasitics
Spread	Food, water, touch	Droplets, fluids	Spores, contact	Food, water, vectors
Example illness	TB, UTI	Flu, HIV	Ringworm, thrush	Malaria, threadworm

Practical Differences in Care

• Bacterial infections often need antibiotics, while viral infections do not.
• Handwashing helps prevent all types, but extra steps may be needed for parasites, like checking for lice.
• Isolation may be needed for infectious viruses to stop spread.
• Extra cleaning can limit fungi in moist areas.

Knowing the Differences in Health and Social Care

Knowing the differences helps you:

• Follow infection control procedures
• Recognise signs of illness linked to each group
• Communicate clearly with colleagues and health professionals
• Provide the right support for people with infections

For example, antibiotics will not treat a cold or flu, which are caused by viruses. Prescribing antibiotics for viral infections is both harmful and wasteful.

Caring for people with chronic fungal infections needs a different approach, like regular skin checks and promoting good foot hygiene.

If you suspect a parasitic infection, such as threadworms, you may need to support the person with hygiene advice and environmental cleaning.

Final Thoughts

Bacteria, viruses, fungi, and parasites all cause disease, but they are very different. Each type has its own structure, way of spreading, and treatment.

• Bacteria are single-celled and can live in many places. Some help us, others make us ill. Treated with antibiotics.
• Viruses are much smaller, need a host cell, and cause many common illnesses. Treated with antivirals or managed with vaccines.
• Fungi can look like moulds or yeasts and cause skin, mouth, or nail infections. Treated with antifungals.
• Parasites live on or in a host, often needing special treatment. They can be internal (worms) or external (lice).

Knowing these differences helps you manage infection risks better and keeps the people in your care safe and healthy. Your understanding supports early identification of possible infections and helps you deliver the best care.

Stay alert for symptoms, changes in people’s health, and always follow your setting’s infection control procedures. This makes a big difference in reducing infections and promoting wellbeing in health and social care settings.