What is a virus?
A virus is an infectious agent that can only replicate within a host organism. Viruses can infect a variety of living organisms, including bacteria, plants and animals. Viruses are so small that a microscope is necessary to visualize them, and they have a very simple structure. They are ten times smaller than bacteria and can cause a number of common illnesses such as flu, chickenpox and the common cold.
Unlike bacteria, there are no “good viruses”, they survive by invading the host cells inside an animal or human to multiply and grow. Following viral replication, the new viruses may go on to infect new hosts.
The primary way to prevent viral infections is vaccination, which administers a vaccine made of inactive viral particles to an unaffected individual and increases the individual’s immunity to the disease.
In general, there is no cure for most common viruses, but vaccinations such as the ‘flu jab contain a weakened version of the virus which stimulates the body to produce antibodies. When the body’s immune system detects a virus, it will usually activate a response to produce antibodies that bind to the virus and kill the infected cell.
The common cold
Causes: Commonly caused by an adenovirus, coronavirus or rhinovirus.
Influenza A (flu)
Causes: Influenza A is the virus which causes seasonal flu.
Causes: Caused by the varicella-zoster virus, mostly affecting babies and children. Can lead to Shingles in later life.
Gastroenteritis (stomach bug)
Causes: Caused by viruses such as rotavirus.
How are viruses spread?
Viruses spread from person to person mainly in droplets that fly out when you cough or sneeze. These tiny drops from an infected person move through the air and land on the mouths or noses of others nearby.
Viruses spread from person to person mainly in droplets that fly out when you cough or sneeze. These tiny drops from an infected person move through the air and land on the mouths or noses of others nearby. Germs are also passed along when you touch mucus droplets from someone else on a surface like a desk and then touch your own eyes, mouth, or nose before you get a chance to wash your hands.
Viruses like the ‘flu can live 24 hours or longer on plastic and metal surfaces like restaurant tables, doorknobs, and cups.
The time a virus can live outside of the body depends on a number of factors such as the type of virus, surface, moisture and temperature.
Viruses tend to survive for longer on hard surfaces than on porous surfaces such as textiles. See our Checklist for where viruses can lurk!
What are bacteria?
Bacteria, also called germs, are microscopic organisms not visible with the naked eye. Bacteria are everywhere, both inside and outside of your body. Bacteria can live in a variety of environments, from hot water to ice. Some bacteria are good for you, while others can make you sick.Bacteria are single-celled, or simple, organisms. Though small, bacteria are powerful and complex, and they can survive in extreme conditions. Bacteria have a tough protective coating that boosts their resistance to white blood cells in the body.
Some bacteria have a tail, called a flagellum. The flagellum helps a bacterium to move around. Other bacteria have sticky hair-like appendages that help bacteria them stick to one other, hard surfaces, and human body cells.
There are many bacteria in the human body, especially in the stomach and mouth. Bacteria are found on surfaces
and in substances such as water, soil, and food.
Responsible for: Wide range of infections, especially amongst people who are already sick.
Caused by: Mainly spread within hospitals/care homes by health care workers, medical or surfaces such as sinks and toilets.
Responsible for: Commonly known as E Coli, can cause sickness, severe diarrhoea, vomiting and abdominal pain.
Causes: Contaminated food, not washing hands after touching animals or going to the toilet/changing nappies.
Responsible for: Legionnaires’ disease, Pontiac Fever, Lochgoilhead Fever
Causes: Widespread in natural water systems and found commonly on shower heads. Caused by breathing in water droplets containing the bacteria.
Responsible for: Food poisoning – fever, vomiting, diarrhoea.
Causes: Listeria can be found in soft cheeses made from unpasteurised milk, raw meat, pate, as well as live in food processing plants.
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 equipment.
Responsible for: Food poisoning – sickness and diarrhoea.
Causes: Salmonella can contaminate meat, eggs, poultry other dairy products. Pets can also carry salmonella and contact with animals or their faeces can infect humans.
Responsible for: Can cause a wide range of infections, particularly affecting the urinary tract, abdomen, blood, wounds etc
Causes: Found almost everywhere, including soil, faeces.
How are bacteria spread?
Bacteria are spread by coughing and sneezing, contact with infected people and contact with contaminated surfaces, food, and water. Bacteria can live on hard surfaces ranging from hours to months, depending on the strain.