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The source of infection for the national outbreak of hepatitis A was probably imported, frozen raspberries. This is shown by the investigation that the Norwegian Food Safety Authority and the Norwegian Institute of Public Health have carried out in connection with the outbreak, which is now considered over.

Image by J Garget from Pixabay

The outbreak of hepatitis A lasted from April to October this year and involved 20 infected people.

Tracing of the source shows that the raspberries are probably no longer on the market. The outbreak is therefore considered over, says senior adviser Heidi Lange at the National Institute of Public Health (NIPH).

Of the 20 who are infected, 18 cases have been confirmed and two are probable. Most are well-adults, but the age range is from ten to 80 years, and 65 per cent are men.

The infected lived in different parts of the country:

  • Viken (9 cases)
  • Oslo (4 cases)
  • Vestfold and Telemark (3 cases)
  • Trøndelag (2 cases)
  • Møre og Romsdal (1 case)
  • Inland (1 case)

The National Institute of Public Health’s analyzes of patient interviews and purchase information show that 18 out of 20 who became infected have eaten fresh or frozen berries of one type or another. Further research showed that half (10 of 20) had eaten frozen, imported raspberries from the same supplier 2-6 weeks prior to illness. The berries were used in various products such as cakes and stirred berries purchased from various bakeries and cafes.

The time from being infected with the hepatitis A virus to becoming ill can be up to six weeks. The long incubation period makes the work of identifying a common source of infection particularly complicated, and it can be difficult to remember what one has eaten so far back in time.

Hepatitis A is caused by a virus (hepatitis A virus, abbreviated HAV) which can cause hepatitis. Symptoms of hepatitis A infection range from mild to more severe, depending on the patient’s age. Classic symptoms are fever, nausea, vomiting, abdominal pain, loss of appetite and eventually dark urine, light stools and jaundice (the skin and whites of the eyes turn yellow).

Some people go through the infection without symptoms, especially in children. The severity of the infection increases with age, but usually the infected recover completely without liver damage and without developing a chronic carrier state with the virus. Most adults may have symptoms for one or more weeks before they get rid of the infection and become immune. Immunity lasts a lifetime. There is an effective vaccine against hepatitis A available. In Norway, it is primarily recommended as a travel vaccine and for close contact with people with proven hepatitis A to prevent them from developing the disease.