Almost 40 people were part of a hepatitis A outbreak in Germany linked to dates from Morocco last year while France, United Kingdom, Netherlands and Sweden reported 18 cases between them.
The 39 patients in Germany fell ill between April and August. Thirty were imported cases and nine people were not abroad during the incubation period.
Results of a case-control study and findings from surveys of people who had not been abroad indicated the outbreak was caused by contaminated dates. Results strongly suggested dried dates sold loosely at markets in Morocco.
Hepatitis A is a viral infection passed from person to person by eating food or drinking water contaminated with the virus. Symptoms usually develop around four weeks after being infected and include mild fever, joint and muscle pain, feeling and being sick, diarrhea, loss of appetite and stomach pain. This can be followed by dark-colored urine, itchiness and yellowing of the skin and whites of the eyes, which is called jaundice.
People ill in France, UK, Netherlands and Sweden
Controls were 16 people also in Morocco during the given period who had contracted Campylobacter with a disease onset between March 1 and April 15, 2018.
Of nine cases infected in Germany, five could be interviewed. None of them indicated a stay abroad in the two months preceding illness. All five reported eating food brought from Morocco and had eaten dates; consumption of figs and nuts was reported by one person.
Sequencing results from 10 patient samples showed HAV subtype IB. More women than men were affected. The median age was 36 years for imported cases (range 10 to 77 years) and 51 years for the autochthonous cases (range 8 to 70 years).
People with the same Hepatitis A virus (HAV) sequence type were also detected in other European countries: eight from France, six from the U.K., three from the Netherlands and one from Sweden. Of these, all but two from France stayed in Morocco and for these cases, consumption of dates from Morocco was identified as a probable source of infection.
Not aware of risk
Most travel-associated illnesses affected people who had been in Morocco between February and April 2018 so it is likely that a contaminated batch of dates was on the market during this period. A second smaller peak in cases from June and July 2018 could mean part of the contaminated batch was available a few months later.
When asked why participants did not get vaccinated against HAV before the trip, it became clear that most of them were not aware of the risk of HAV infection in Morocco. Findings suggest that hepatitis could be avoided if travelers were better informed about the risks of infection.
Other reasons for not getting vaccinated were ignorance about the availability of a HAV vaccine and a negative attitude to vaccination.
The survey also showed travelers often bring food back to Germany. Five of the cases that did not go abroad were explained with the consumption of dates brought as a gift and it is plausible the same reason was behind illness of the other cases with no travel history.
RKI, WHO and GOARN
Meanwhile, the World Health Organization has designated the Information Centre for International Health Protection (INIG) at the Robert Koch Institute (RKI) as a WHO Collaborating Centre for the Global Outbreak Alert and Response Network (GOARN).
In the next four years, RKI will work with national and international partners to support WHO in identifying and addressing global health threats. RKI will deliver advice to the WHO, support implementation of GOARN projects, devise and test training activities, foster knowledge-sharing and help develop the network.
The GOARN includes more than 220 institutions from 75 countries that focus on rapid disease outbreak detection and response and is coordinated by WHO.
Lothar H. Wieler, president of the RKI, said in a globalized world, pathogens can spread quickly.
“But the countries affected also need support in building efficient health systems so that outbreaks of infection can be avoided or quickly contained,” he said.
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