Viral food poisoning

Most cases of food poisoning are bacterial in nature but there are incidences of food poisoning which have been caused by a particular type of virus.

There are in fact, several groups of viruses responsible for food poisoning which include:

• Noroviruses
• Rotavirus
• Adenovirus

Each of these is discussed in more detail within this section.

Viral food poisoning occurs as a result of contact with someone who is already infected; sharing food with an infected individual; inadequate washing of the hands after contact with food or water which is contaminated by infected faeces; touching a surface which has become infected by a virus and then touching your mouth.

What is a virus?

A virus is a tiny infectious agent which can invade any type of organism – and that includes humans. They have a variety of shapes, e.g. ‘double helix’ and are pathogenic in nature.

A virus consists of two maybe three sections:

• Genes, e.g. DNA
• Molecules: these help to carry these genes
• Protein layer which protects these genes (capsid)

When a virus invades an organism, for example, the human body, it invades cells (known as ‘hosts’) within the body and reproduces itself at an incredible rate. In other words, it produces millions of copies of itself within a short space of time.

Some groups of viruses destroy any host cells that they have invaded: others cause a host cell to multiply but without any ill effects. But there are others which have the ability to cause cancer.

Where are viruses found?

Viruses can be found in humans and the environment. Examples of these include soil, air, animals, lakes, streams, food and other people who are already infected.

How do you contract a virus?

Viruses can spread via airborne contact (e.g. sneezing), person to person contact or from eating contaminated food or drinking infected water.

Norovirus and rotavirus are transmitted through contact with an infected individual; touching a contaminated surface or object or the consumption of infected food and/or water.

Seasonal viruses

Viral infections are seasonal: you are more likely to contract norovirus or rotavirus in the winter months than any other time of the year.

A good example of this is an increase in the number of norovirus cases each January which is known as the ‘winter vomiting bug’.However, it is possible to get this illness at any time in the year.

One way of approaching this is to assume that you can contract viral food poisoning at any time in the year.