More details about norovirus resistance

The symptoms of gastroenteritis include nausea, vomiting, diarrhea, abdominal cramping, fever and weakness. They are usually short-lasting and disappear within 48 hours; the patients do not require professional medical attention. Children, in whom this virus is the main cause of gastroenteritis, elderly people and patients with chronic diseases, however, need to be followed, mainly because of the danger of dehydration from loss of fluids.

Genetic resistance

Norovirus is highly contagious; nevertheless, some people do not become infected upon exposure. 20% of Europeans are thought to be resistant to it. This indicates a special trait which turns out to be genetic. The FUT2 gene plays a decisive role; it is responsible for the formation of proteins called carbohydrates H type 1 that are found in the intestinal mucosa and in mucous gland discharge. One fifth of Europeans do not possess these proteins due to a mutation in both FUT2 genes and the entry of the virus into the body, and infection, are thus prevented.

Resistance to infection with noroviruses, or the presence of a certain mutation and development of a non-expressing individual type, has certain advantages as well as disadvantages. The obvious advantage is the resistance to noroviruses as well as a supposedly lower chance of acquiring the HIV infection. The disadvantage is a higher chance of infection with certain bacteria, such as E.coli. A problem can also appear in the case of breast-feeding mothers who are resistant to infection. If the baby does not have genetic resistance like the mother does, it needs antibodies for protection against infection. Babies receive antibodies in the mother's milk. However, since resistant mothers have never been infected with noroviruses, they have not developed immunity. Thus, there are no antibodies against noroviruses in their milk and their babies may become infected.

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