Contaminated food could be playing a role in an increase of Hepatitis A infections, according to European officials.

Clusters and outbreaks of hepatitis A virus (HAV) genotype IB with four unique but related HAV sequences have been reported in six European countries and the United Kingdom.

More than 300 cases with identical or closely related HAV strains have been identified in Austria, Germany, Hungary, the Netherlands, Slovenia, Sweden, and the UK.

Epidemiological and microbiological data so far suggests human-to-human transmission and also contaminated food as possible sources of infection, said the European Centre for Disease Prevention and Control (ECDC).

Possible foodborne transmission should be investigated when several infections are reported within a short period. Scaling up surveillance to detect and investigate sporadic and clusters of cases with food safety authorities is essential, said ECDC.

The agency warned that cases have been reported in September, suggesting the chain of transmission may still be ongoing and more infections were likely.

In February, Hungary reported an outbreak of HAV genotype IB with the first case in December 2021. A total of 161 cases, mostly males but 22 females, have been confirmed with this strain. Some infected people were men who have sex with men, suggesting transmission among sexual contacts. Several patients were hospitalized.  

Berry recall
In July, a foodborne outbreak was linked to a restaurant in Hungary, wher 16 people fell ill also with HAV IB infection. Some patients had cold soup made with frozen berries. This prompted a recall of Ardo Fruitberry mix, produced and packed by a subcontractor of the group in Poland.

Countries listed in a Rapid alert System for Food and Feed (RASFF) reported as being sent affected product included Austria, Belgium, Croatia, Germany, Greece, Hong Kong, Ireland, Netherlands, Romania, Spain, Sweden and the UK.

In the UK, no source of infection has been identified for 76 cases, but epidemiological investigations indicate possible foodborne infections and person-to-person transmission. Germany, the Netherlands, and Sweden have nine cases infected matching the UK strain. No clear risk factors for infection such as travel history or consumption of berries have been found.

HAV is highly transmissible through contaminated water, food, and via the fecal–oral route among close contacts, with an average incubation period of four weeks, ranging from two to six weeks. The virus is resistant to preservation methods like freezing.

Good hand hygiene, including thoroughly washing hands with soap after using the bathroom and before preparing or eating food, plays an important role in preventing the spread of hepatitis A.

Hepatitis A is spread when someone ingests the virus through close contact with an infected person or by having contaminated food or drinks. Symptoms include inflammation of the liver, fever, low appetite, nausea, vomiting, diarrhea, muscle aches, and yellowing in the whites of the eyes and the skin (jaundice).