Fifteen cases of hepatitis A virus (HAV) similar to those involved in a recent HAV outbreak in Italy linked to frozen berries have been recorded in Ireland since April.

According to the HSE's Health Protection Surveillance Centre (HPSC), the hepatitis A virus due to genotype IA infection in the Irish cases is similar to that in a major HAV outbreak in Italy earlier this year, which was associated with the consumption of mixed frozen berries.

However, the HPSC says to date, no definite source of the infection outbreak in Ireland has been identified, although frozen berries imported into this country are strongly suspected.

Symptoms of HAV infection include fatigue, fever, nausea, appetite loss and jaundice.

Ten of the 15 people who recently contracted HAV were admitted to hospital. Only one of the 15 cases had a history of travel to Italy during the incubation period.

The Food Safety Authority (FSAI), along with the HSE and the Department of Agriculture, have been trying to trace the source of the outbreak.

The HPSC says in Ireland, people who have become infected reported eating a number of different foods made with frozen berries such as smoothies, juices, desserts, yogurts and cheesecake.

This has added to the difficulty in identifying suspect food batches, according to the HPSC, as has the lengthy incubation period of HAV - up to 50 days - which makes people's food history recall very challenging.

The HPSC says the traceability investigation is complicated by the fact that the global nature of trade means that the imported frozen berry supply chain involves a large network of players in many different countries.

The most recent case recorded here was on August 9, and  the investigation of the likely source is continuing.

In Italy, the HAV bug was detected in samples of berries imported from a number of different countries, although as in Ireland, a definitive source of the outbreak there has yet to be confirmed.

The FSAI, back in June, advised the public as a precautionary measure to boil any imported frozen berries for at least one minute before consumption.