Australian hepatitis A cases linked to imported dates
Six people in Australia were part of a hepatitis A outbreak this past year after eating dates from Jordan, according to a study.
Researchers said it was the first known hepatitis A outbreak in the country linked to imported fresh Medjool dates. A connection was identified with an outbreak in the United Kingdom despite implicated dates being picked months apart and coming from different farms.
Between June and September 2021, six genetically identical hepatitis A cases were reported in New South Wales and the Australian Capital Territory. All sick people reported the date of consumption during their exposure period. Implicated dates were positive for hepatitis A virus (HAV), according to the study published in Communicable Diseases Intelligence.
Australian border closures in response to the COVID-19 pandemic meant that a common locally-acquired, and not a travel-acquired, the source was suspected. Plus, awareness of a hepatitis A outbreak in the UK that sickened at least 31 people, also associated with date consumption, allowed for early hypothesis generation and investigation, possibly preventing more illnesses.
When borders were closed there was less than one hepatitis A case per month nationally. Until June 2021, all cases notified in New South Wales during this period were linked to returning citizens, except one, which was due to the consumption of previously recalled imported frozen food.
Link to eating dates
The first patient in June 2021 reported fresh Medjool date consumption during their exposure period, but was unable to identify the product to assist traceback. In July, it was found that this case was genetically identical to samples from sick people in the UK outbreak linked to dates from Jordan. The third sick person was able to report a specific brand of imported dates.
Four of six patients reported either eating the implicated brand or consuming dates purchased from a site that sold the affected product.
Five patients with genotype IB lived in New South Wales and one in the Australian Capital Territory (ACT). The median age of cases was 26 but ranged from 15 to 53 years old and five were male. Four people required hospitalization.
Officers of the NSW Department of Primary Industries collected a 1-kilogram unopened box of the suspected Medjool dates from a Sydney supermarket. Two of the 10 subsamples had HAV detected. As the positive date sample could not be sequenced, human sequences could not be genetically linked to the implicated food product.
In August 2021, the Australian importer of the fresh Medjool dates produced in Jordan conducted a recall. This importer distributed dates into New South Wales and Victoria. It is thought they may have been sent to the ACT through an unidentified third party.
A holding order was placed on Medjool dates from the Jordanian supplier. This meant that upon import into Australia, any consignments of dates from this supplier would be held at the border until authorities in Jordan provided assurance that the risk of HAV contamination had been mitigated. This order has since been lifted.
Connection to UK outbreak
A report on the outbreak of hepatitis A in England and Wales linked to dates from Jordan alerted Australian public health investigators to the issue and led to a question about date consumption being added to the national surveillance questionnaire for hepatitis A.
The HAV outbreak strain linked to dates in Australia was identical to the strain in England and Wales. However, no common grower, manufacturer, or importer could be identified. Jordanian authorities said the batches of dates in each outbreak had been picked and processed months apart and came from different farms along the Jordan River.
One explanation for the common strain in different outbreaks caused by the same food product is that it represents an endemic, circulating strain in the country of origin. Or, there may be a common source between the farms, such as person-to-person transmission among date harvesters, said researchers.
Scientists said more investigations are needed to understand the food safety risks associated with fresh Medjool dates and additional risk management measures in Australia on the import of such dates may be required.
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