Two distinct Hepatitis A virus strains are causing infections in travelers returning from Morocco, according to researchers.
From January to June 2018, two outbreaks are ongoing affecting people coming back from Morocco and cases in Europe without travel history, resulting in 163 patients in eight European countries. In the first cluster, 55 cases of Hepatitis A virus (HAV) infection have been reported.
The UK has the highest number of cases with 36. Denmark, France, Germany, Ireland, the Netherlands, Spain, and Sweden each reported between one and six infections.
The onset of symptoms ranges between mid-January and mid-June. Cases are between three and 81 years old and 26 out of 55 of them are female. Three cases reported travel to Morocco within 50 days before disease onset.
One case in their early 50s who had no known pre-existing conditions died as a result of HAV infection.
“The occurrence of closely related strains of HAV have been observed in other major foodborne outbreaks. It is, however, still possible that cases actually belong to separate transmission chains,” said the researchers.
In a previous assessment, the European Centre for Disease Prevention and Control said the relative homogeneity of the viral strains associated with outbreak cases suggests foodborne transmission could be associated with a single food product distributed in several EU countries.
The second cluster consists of 33 confirmed cases; 25 travel-related and eight without travel history. Dates are the suspected vehicle but the investigation is ongoing.
Most infections were reported by Germany with 15, France with eight and the UK with six, Sweden and the Netherlands have reported one and three cases, respectively.
The onset of symptoms ranged from the beginning of April to mid-May. All travel-related cases reported travel to Morocco in March.
The age range of cases was between eight and 76 years and 55 percent were female.
A case-control study of German cases is ongoing and 16 travel-related cases (eight confirmed, eight possible) and four autochthonous cases have been interviewed.
All autochthonous cases consumed food items brought home by travelers returning from, with dates being the only product reported in all four cases.
Among the 16 travel-associated cases, 14 reported date consumption during their stay in Morocco.
In France, one patient brought dates back from Morocco and ate them with two other people, all three of whom developed symptoms after the same incubation time.
The occurrence of two concurrent HAV clusters in the first six months of 2018 serves as a reminder of the risk of contracting hepatitis A in Morocco, said researchers.
“The outbreaks described here illustrate the increased risk that non-immune travelers face when visiting HAV-endemic areas like Morocco,” they said.
“All of the eight countries where cases occurred have explicit recommendations of hepatitis A vaccination for travel to endemic countries, in accordance with World Health Organization recommendations.
“Finally, as hepatitis A vaccination does not protect from many other foodborne infections additional recommendations to follow sound hygiene including hand hygiene should be given to the public.”