Wednesday, December 7

Hepatitis viruses in food: how do they get there and how do they resist?


Hepatitis is a group of diseases characterized by inflammation of the liver and causing liver disease. There are several types of hepatitis viruses, as we explain in this article, which are named with the letters of the alphabet (A, B, C, D and E), with significant differences between them.

Alert for hepatitis A virus in frozen forest fruits

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Only two of them, viruses A and E, considered the most common and the cause of acute epidemic hepatitis, are transmitted through the contaminated food and water.

Hepatitis A virus, one of the most common causes of foodborne infection

Hepatitis A (HA) is an inflammatory disease of the liver caused by the hepatitis A virus (HAV), which is found in the feces and blood of infected people and is highly contagious.

is transmitted especially by the fecal-oral routethat is, when an uninfected person ingests water or food contaminated by the feces of an infected person, or by close personal contact (although it can also be transmitted by certain sexual practices).

Hepatitis A is the most frequent of the viral hepatitis and in Spain it has been mandatory individual declaration since 1997. During the last two years (2020-2021) the number of cases of HA in Spain has decreased significantly.

It is something that experts attributed in part to coexistence with the SARS-CoV-2 virus, which has conditioned a large decrease in most vaccine-preventable diseases.

It usually causes a mild infection, with complete recovery after a few weeks, according to the Catalan Association of Liver Patients (ASSCAT), with symptoms ranging from fever, loss of appetite, stomach cramps, jaundice, dark urine, and fatigue. Recovery ends when the body expels the infection and the disease does not become chronic.

Foods most implicated in hepatitis A

Foods associated with outbreaks are:

  • Seafood grown in polluted water areas consumed raw or undercooked: oysters, scallops, scallops or mussels from harvesting or farming areas where the waters have fecal contamination.
  • Contaminated prepared foods by carrier handlers: we are talking mainly about those preparations that are not cooked after handling, such as vegetables, salads, fruits, fish, milk and dairy products such as ice cream.
  • Contaminated vegetable products by irrigating with contaminated water: lettuce, onions, tomatoes, parsley, etc.
  • water transmission: deficient water supply networks or wastewater collection with problems.

The hepatitis A virus is very resistant, remaining infectious even after months at room temperature. It resists moderate heat (60ºC for one hour) and is not destroyed by undercooked foods. It is deactivated by cooking, for at least five minuteswith ultraviolet radiation or chlorine treatment.

Personal hygiene measures (frequent hand washing) and environmental measures (proper water treatment and storage, washing and cooking of food) are key to preventing infection.

Coexistence at home with a person with hepatitis A forces us to take extreme hygiene measures to avoid transmission: not sharing plates or cutlery, washing our hands well, etc. The good news is that this type of virus has a vaccine that is almost 100% effective.

Hepatitis E virus, considered a potentially zoonotic disease

As in the previous case, the hepatitis B virus (HBV) can be transmitted through the consumption of contaminated food or water. It is considered a disease potentially zoonoticthat is, it is transmitted from animals to humans, of certain genotypes identified in pigs and wild boars, as well as in birds or rabbits.

Hepatitis E is transmitted primarily by the fecal-oral route and by ingesting:

  • Water contaminated with feces.
  • Products derived from infected animals: for example, pork, pâté or game meat.
  • Contaminated food such as vegetables or shellfish.

This virus, which does not usually cause chronic disease, can also be transmitted by transfusion of infected blood products and from a pregnant woman to the fetus. With an incubation period of about 40 days, it reaches its maximum serum values ​​between 30 and 120 days after infection.

The jaundice phase is characterized by yellowing of the skin and mucous membranes, which may be accompanied by a flu-like picture, with general malaise, loss of appetite, joint pain, fever, nausea, vomiting, diarrhoea, etc.

Prevention goes through extreme hygienic measuresavoid the consumption of non-potable water and contaminated food since, unlike the hepatitis A virus, there is no specific vaccine against the hepatitis E virus.

The European Food Safety Authority (EFSA) recommends cooking pork, wild boar and deer meat and offal, especially liver, since pigs and wild boar are considered the main carriers of hepatitis E.

Prognosis of hepatitis A and E viruses

According to the World Health Organization (WHO), these two viruses remain in the environment and can resist the processes that are usually used to inactivate or control pathogenic bacteria, hence the important role of prevention and hygiene.

Epidemic acute hepatitis caused by viruses A and E do not become chronic and are usually cured spontaneously in most cases. Despite everything, it is estimated that only 1% may have a more serious prognosis that requires treatment.

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