Norovirus and hepatitis A virus, how they are transmitted and how to prevent them

In the last few hours, the Ministry of Health has requested the withdrawal of frozen berries due to the possible presence of norovirus and of hepatitis A virus. These viral strains can cause symptoms especially affecting the digestive system, although sometimes the infection occurs practically without symptoms.
But how are these viruses transmitted? How can the symptoms be addressed, considering that there are no specific antiviral therapies? And above all, can we focus on prevention?
Based on information on the epicenter website of the Higher Institute of Health and Scientific Research, here is a handbook to learn more about these invisible enemies of health.

What is the hepatitis A virus and how is it transmitted?

Hepatitis A is one of the many dangers that can hide in foods. The disease is caused by an RNA virus that Resists up to temperatures of 60 degrees, but fortunately it is destroyed by boiling. In sea water it can survive for up to two months and this explains the reason for the risk you run by eating raw shellfish and seafood coming from uncontrolled areas.
In general, other potentially polluted foods are: raw vegetables, water and unpasteurized milk. Furthermore, it may be at risk direct contact with the hands of a person who has just suffered the infection, while the passage of the virus through the blood is highly unlikely, because the virus remains in the circulating blood for only a week.
The virus generally enters the body through food and is eliminated in feces. Through the portal vein it reaches the liver, where it multiplies causing the death of numerous cells. Then it is eliminated with the bile and enters the intestine where it is expelled with the feces which can infect.

What symptoms does hepatitis A cause and how is it prevented?

Normally the infection is benign and tends to self-limit over time, although the duration of the disease can vary between two and ten months. In fact, the virus has an average incubation period of one month. After this phase, signs of the disease may appear: weakness, feeling sick and sometimes even fever with maximum peaks of even 39 degrees. These symptoms, which are not always present, are accompanied by an increase in blood values transaminases (particular liver enzymes) and bilirubina substance that is produced by the destruction of hemoglobin present in red blood cells.
Since there is no specific therapy for the virus, Treatment aims to control the symptoms and signs of the infection, especially if there is severe liver damage. For prevention there is a vaccine, which can also be administered together with the one against hepatitis B, is protective after about a month from the first administration and is very effective. Obviously you need to ask your doctor for directions but in general vaccination is recommended for those who travel a lot or is found in areas at high risk due to poor hygiene in food preparation, as well as canteen operators and food manufacturing companies. More generally, however, vaccination is more recommended for adults because it has been seen that in children the infection occurs more frequently without giving appreciable clinical signs.

What is norovirus and how is it transmitted

Noroviruses are RNA viruses and are considered among the most common culprits of acute gastroenteritis of a non-bacterial nature. Among these strains one of the most common is the so-called Norwalk virusso called due to the appearance of a very serious epidemic in the Ohio city of the same name towards the end of the last century.
Due to its ability to spread in closed environments, norovirus tends to create microepidemics in facilities such as retirement homes or schools. Sometimes it also happens that there are cases concentrated on cruise ships. It must be said that transmission between humans or through the environment is extremely simple, given that it is a highly infectious viral strain. Generally, therefore, the virus is transmitted from person to person, via the fecal-oral route or through breathing, through infected water or food and, given that it manages to survive for a long time in the environment, also through contact with contaminated surfaces. More often, however, the infection is transmitted through foods (e.g. raw seafood, salads, berries, contaminated water, cold foods) or otherwise with contaminated water.

What symptoms does norovirus infection cause and how is it prevented?

As reported on the website of the Istituto Superiore di Sanit√† “the incubation period of the virus is 12-48 hours, while the infection lasts from 12 to 60 hours. The symptoms are those common to gastroenteritis, namely nausea, vomiting, especially in children, watery diarrhea and abdominal cramps. In some cases, a slight fever also occurs. The disease usually has no serious consequences and most people recover in 1-2 days without complications.”
All this helps to understand how the treatment is symptomatic, aimed at counteracting nausea and diarrhea. But these modes of presentation also reveal how attention needs to be paid to risk of dehydration, in particular for very young children, the elderly and those suffering from chronic metabolic or cardiovascular diseases. In these cases it is therefore necessary to consume liquids in quantity, integrating with saline solutions to compensate for the risk of a drastic drop in liquids and mineral salts.
Unfortunately There are no specific vaccines for norovirus nor is it thought that long-term immunity exists. This is why the virus can infect the same person several times in a lifetime.

WHO indications to reduce the risks of food poisoning

In addition to the use of pure or boiled water, here are the most important rules from the World Health Organization:

  • choose foods that have been treated to make them safe (wash salad well, consume pasteurized milk and fresh or frozen poultry)
  • cook the food thoroughly (only complete cooking destroys the germs in the meat. You need to reach 70 degrees in every part of the poultry)
  • consume cooked foods immediately (as they cool, microbes develop and the danger increases as the hours pass)
  • store cooked foods well (if you have to use them after more than five hours, bring them to at least 60 degrees or less than 10)
  • reheat already cooked foods well (the food must be brought to 70 degrees to destroy any germs that may have developed)
  • do not bring together cooked and raw foods (germs from raw foods can develop in cooked foods, for example with raw chicken meat)
  • do not use the same knife for raw and cooked meats (the risk of transmitting germs exists)
  • wash your hands often (at least after handling raw meat and fish or after contact with pets)
  • clean the kitchen well (cloths, crumbs and leftovers can keep germs)
  • seal food hermetically (to avoid contact with insects or other animals).