Knowing the Different Germs: Bacteria Vs Viruses

Bacteria

Bacteria are simple single-celled organisms that are only visible under a microscope. Depending on their genetic material, they can be spherical or rod-shaped and, when multiplying, grow in rows or in uniform and non-uniform groups. We need bacteria (microflora) to aid digestion and produce vitamins such as vitamin K. In a healthy person, microflora should not cause any problems and actually helps prevent infection. In vulnerable people, such as children and the elderly, maintaining this balance is much more important.

What are the most common infectious bacteria? How are they transferred and what types of illness do they cause?

E. coli

E. coli is rod-shaped, resembling a grain of long-grain rice. Most strains are harmless and live naturally in the lower intestine, but some can cause serious illness. Food-borne strains can lead to severe gastroenteritis, fever and kidney damage, with children and older adults being particularly vulnerable. These harmful strains release toxins that contribute to illness.

Commonly associated with meat products, E. coli enters the food chain through poor hygiene practices that allow faecal matter to contaminate raw meat. Prevention is the best defence. Thoroughly cooking meat, maintaining excellent food hygiene, using a bactericidal cleaner with a 99.999% kill rate (EN1276), and regular hand washing all help reduce the risk.

Salmonella

Like E. coli, Salmonella is rod-shaped and causes gastroenteritis, with an incubation period typically between 12 and 36 hours.

Found in dairy products such as milk and eggs, as well as raw chicken and some processed foods, Salmonella is one of the most common causes of food poisoning in the UK. It can survive for long periods and is difficult to eradicate, making excellent food handling practices, prevention of cross-contamination and thorough hand hygiene essential.

Viruses

Viruses consist of genetic material enclosed within a protein coating. They differ significantly from other micro-organisms in both structure and function. Viruses act as parasites, infecting host cells and replicating thousands of times. As they survive only briefly outside a host, they often rely on contaminated food and surfaces to spread from person to person.

Hepatitis A

Although Hepatitis A has a relatively low mortality rate, its long incubation period means it can be easy to overlook. It is commonly spread through poor personal hygiene when handling food, or by consuming contaminated water or ice. Hepatitis A is highly infectious and attacks the liver, often causing jaundice that affects the skin and eyes.

Other symptoms may include fever, weakness, fatigue, joint pain, loss of appetite and, in some cases, severe itching.

Influenza

Influenza is primarily spread through respiratory droplets produced when an infected person coughs or sneezes, or by touching contaminated surfaces before touching the eyes, nose or mouth. Symptoms usually develop within 48 hours of infection.

Unlike the common cold, influenza often begins suddenly and may include a high fever, coughing, sneezing, severe muscle aches, chills and nausea. Regular hand washing, good hygiene and self-isolation when unwell all help reduce transmission.

Norovirus

Often referred to as the "winter vomiting bug", Norovirus spreads by touching contaminated surfaces, eating food prepared by infected people or coming into close contact with someone carrying the virus. Symptoms usually appear within one to two days and typically last around two days.

Norovirus causes gastroenteritis, resulting in vomiting and diarrhoea. Although unpleasant, it usually resolves without long-term effects. Regular hand washing, avoiding alcohol hand gels where soap and water are available, and self-isolation while symptomatic can help prevent its spread.

COVID-19

Coronaviruses infect mammals and birds and can sometimes spread between species. COVID-19 primarily affects the respiratory system, causing symptoms that range from mild cold-like illness to more serious conditions such as bronchitis and pneumonia. The virus has a distinctive spiked outer layer that helps it attach to and infect host cells.

COVID-19 is spread through respiratory droplets produced when an infected person talks, coughs or sneezes. These droplets can remain suspended in the air for a period before settling onto surfaces, where they may remain viable for some time depending on environmental conditions.