A nationwide serosurvey of hepatitis E virus antibodies in the general population of Portugal.

Background: Evidence has shown that Hepatitis E virus (HEV) genotype 3 is autochthonous in industrialized countries due to zoonotic transmission through direct contact or consumption of raw or undercooked meat from domestic swine or wild boar. As there is lack of data on seroprevalence of HEV in the general Portuguese population, a wide survey was conducted as part of the HEPeCONTROL project (60DT2), under EEA grants funding.

Methods: Sera from a representative sample of the Portuguese population (n = 1656) at different geographic locations (30 territorial units), and age (0-99 years) were collected between July 2015 and February 2016. The sera were tested for the presence of anti-HEV IgG and IgM by EIA using one of the two most commonly used commercial immunoassays in Europe.

Results: The overall HEV IgG seroprevalence was found to be 16.3% increasing with age (P < 0.05) from 0.6% in the 0-9 years group to 30.1% in people older than 70 years. The seroprevalence also varied geographically with generally higher seropositivities (25-30%) in the most rural areas of Portugal. However, the geographical differences were not statistically significant (P > 0.05). Out of 1656 samples, 8 were positive for anti-HEV IgM indicating current of recent HEV infection but no significant differences were found concerning age groups, regions and sex.

Conclusions: The present nation-wide survey provides insight in the epidemiology of HEV in Portugal and confirms that HEV is endemic in the Portuguese population.