Prevalence and phylogenetic analysis of hepatitis E virus in pigs, wild boars, roe deer, red deer and moose in Lithuania

Abstract

BackgroundHepatitis E virus (HEV) is one of the major causes of acute viral hepatitis worldwide. In Europe, food-borne zoonotic transmission of HEV genotype 3 has been associated with domestic pigs and wild boar. Controversial data are available on the circulation of the virus in animals that are used for human consumption, and to date, no gold standard has yet been defined for the diagnosis of HEV-associated hepatitis. To investigate the current HEV infection status in Lithuanian pigs and wild ungulates, the presence of viral RNA was analyzed by nested reverse transcription polymerase chain reaction (RT-nPCR) in randomly selected samples, and the viral RNA was subsequently genotyped.ResultsIn total, 32.98 and 22.55% of the domestic pig samples were HEV-positive using RT-nPCR targeting the ORF1 and ORF2 fragments, respectively. Among ungulates, 25.94% of the wild boar samples, 22.58% of the roe deer samples, 6.67% of the red deer samples and 7.69% of the moose samples were positive for HEV RNA using primers targeting the ORF1 fragment. Using primers targeting the ORF2 fragment of the HEV genome, viral RNA was only detected in 17.03% of the wild boar samples and 12.90% of the roe deer samples. Phylogenetic analysis based on a 348-nucleotide-long region of the HEV ORF2 showed that all obtained sequences detected in Lithuanian domestic pigs and wildlife belonged to genotype 3. In this study, the sequences identified from pigs, wild boars and roe deer clustered within the 3i subtype reference sequences from the GenBank database. The sequences obtained from pig farms located in two different counties of Lithuania were of the HEV 3f subtype. The wild boar sequences clustered within subtypes 3i and 3h, clearly indicating that wild boars can harbor additional subtypes of HEV. For the first time, the ORF2 nucleotide sequences obtained from roe deer proved that HEV subtype 3i can be found in a novel host.ConclusionThe results of the viral prevalence and phylogenetic analyses clearly demonstrated viral infection in Lithuanian pigs and wild ungulates, thus highlighting a significant concern for zoonotic virus transmission through both the food chain and direct contact with animals. Unexpected HEV genotype 3 subtype diversity in Lithuania and neighboring countries revealed that further studies are necessary to understand the mode of HEV transmission between animals and humans in the Baltic States region.

Wild Boar as a Sylvatic Reservoir of Hepatitis E Virus in Poland: A Cross-Sectional Population Study

“…Additionally, in Europe, the seroprevalence of infections in wild boars ranged from 4.9% in Italy [ 28 ] to 57.4% in Spain [ 29 ]. A high percentage of infected wild boars was shown in Lithuania (25.9%) [ 30 ], Corsica (29.9%) [ 31 ], Slovenia (30%) [ 32 ], Belgium (34%) [ 33 ] and in the central part of Italy (56.2%) [ 34 ]. Regional differences in the occurrence of the frequency of HEV infections in wild boars in Poland were observed.…”

Increasing Hepatitis E Virus Seroprevalence in Domestic Pigs and Wild Boar in Bulgaria

“…Recent studies in Europe revealed molecular evidence for HEV infection in wild boar and high HEV seroprevalences [24][25][26][27][28]. The HEV disease-dynamic in wild boar is similar to domestic pigs; the infection frequency also increases with age as well as the possibility of viral chronification [29].…”

Antibodies Against Hepatitis E Virus (HEV) in European Moose and White-Tailed Deer in Finland

“…In animals, zoonotic HEV is usually subclinical (Yugo and Meng 2013 ). Studies of HEV in cervids have mostly focused on European roe deer ( Capreolus capreolus ), red deer ( Cervus elaphus ), and sika deer ( Cervus nippon ) but fallow deer ( Dama dama ), white-tailed deer ( Odocoileus virginianus ), and European moose ( Alces alces ) have also been studied (Yu et al 2007 ; Zhang et al 2008 ; Reuter et al 2009 ; Boadella et al 2010 ; Forgách et al 2010 ; Rutjes et al 2010 ; Dong et al 2011 ; Medrano et al 2012 ; Lin et al 2014 , 2015 ; Larska et al 2015 ; Lhomme et al 2015 ; Serracca et al 2015 ; Kubankova et al 2015 ; Zhang et al 2015 ; Kukielka et al 2016 ; Neumann et al 2016 ; Roth et al 2016 ; Anheyer-Behmenburg et al 2017 ; Di Bartolo et al 2017 ; Thiry et al 2017 ; Weger et al 2017 ; Spancerniene et al 2018 ; Trojnar et al 2020 ).…”

“…However, only HEV-3 has been found in deer in Europe (Reuter et al 2009 ; Boadella et al 2010 ; Forgách et al 2010 ; Serracca et al 2015 ; Kubankova et al 2015 ; Kukielka et al 2016 ; Anheyer-Behmenburg et al 2017 ; Di Bartolo et al 2017 ; Thiry et al 2017 ; Spancerniene et al 2018 ). HEV seroprevalences have ranged 0.0–13.9% in Europe, and related HEV RNA prevalences have ranged 0.0–34.4% (Reuter et al 2009 ; Boadella et al 2010 ; Forgách et al 2010 ; Rutjes et al 2010 ; Larska et al 2015 ; Lhomme et al 2015 ; Serracca et al 2015 ; Kubankova et al 2015 ; Kukielka et al 2016 ; Neumann et al 2016 ; Roth et al 2016 ; Anheyer-Behmenburg et al 2017 ; Di Bartolo et al 2017 ; Thiry et al 2017 ; Spancerniene et al 2018 ; Trojnar et al 2020 ). HEV RNA prevalences over 10% have been reported in Hungary (Reuter et al 2009 ; Forgárch et al 2010 ), Lithuania (Spancerniene et al 2018 ), Italy (Di Bartolo et al 2017 ), and Spain (Boadella et al 2010 ; Kukielka et al 2016 ).…”