BfR: Viruses

Viruses

We cannot only become infected by viruses through direct contact but also through foods. BfR examines and assesses the risks of viral infections following the consumption of different foods. In this connection BfR hosts the National Reference Laboratory for Foodborne Viruses.

What are viruses?

Viruses are the smallest pathogens which cause infections. They only consist of genetic material which is surrounded by a protective envelope of fats and/or protein.

As opposed to bacteria, viruses have no own metabolism and cannot multiply themselves. They need the cell of a living organism, the so-called host.

Overview of some viruses

Noroviruses cause gastro-intestinal diseases in all age groups which are characterised by vomiting and diarrhoea. They are highly infectious and can be transmitted both directly from human to human and indirectly through contaminated surfaces or foods.

Rotaviruses are pathogens which cause diarrhoea. Mainly infants can have very severe courses of disease. Outbreaks frequently occur in day care centres. The virus is easily transmitted from human to human but also through contaminated foods.

Hepatitis A viruses cause acute inflammations of the liver (hepatitis). Their transmission is either directly from humans to humans or indirectly with contaminated foods serving as transmission vehicle. Many hepatitis A diseases in Germany are contracted abroad. Only four weeks after the infection the first symptoms appear.

The comparatively rare disease caused by hepatitis E viruses is very similar to hepatitis A. The virus is found in countries with a low hygiene standard in contaminated drinking water or foods but also in pigs and wild boar in central Europe, including Germany. The possibility of transmission from food made of them, which is insufficiently heated before consumption, is discussed.

The influenza A virus H5N1 – also known as "bird flu" – can cause severe general diseases and pneumonia in humans. It originates from infected poultry and can be transmitted through close contact with the latter in individual cases to humans. Transmissions via foods do not seem to play a role.

The disease caused by the influenza A virus H1N1 – referred to as "swine flu" – has a slightly milder course. In most cases it causes a moderately developing general disease in humans affecting the respiratory tract. It is easily transmitted between humans by droplet infection. An involvement of foods at the transmission of this virus is so far not known.

Legal basis

Decision 99/131/EC and Regulation (EC) 882/2004.