Longitudinal survey of hepatitis E virus in extensively raised pigs in Spain.
Tomás Fajardo-Alonso1
Ignacio García-Bocanegra2,3
María A Risalde4,5
Antonio Rivero-Juárez4,6
Saúl Jiménez-Ruiz2,7
David Cano-Terriza2,8
María Casares-Jiménez4,6
Eduardo Laguna9,10
Pelayo Acevedo7
Mario Frías2,4,6
Joaquín Vicente7
Antonio Rivero4,6
Javier Caballero-Gómez2,4,6
Affiliations10 institutions
Departamento de Sanidad Animal, Grupo de Investigación GISAZ, UIC Zoonosis y Enfermedades Emergentes ENZOEM, Universidad de Córdoba, Córdoba, Spain.
Departamento de Sanidad Animal, Grupo de Investigación GISAZ, UIC Zoonosis y Enfermedades Emergentes ENZOEM, Universidad de Córdoba, Córdoba, Spain
CIBERINFEC, ISCIII - CIBER de Enfermedades Infecciosas, Instituto de Salud Carlos III, Madrid, Spain. Electronic address: [email protected].
CIBERINFEC, ISCIII - CIBER de Enfermedades Infecciosas, Instituto de Salud Carlos III, Madrid, Spain
Departamento de Anatomía y Anatomía Patológica Comparadas y Toxicología, Grupo de Investigación GISAZ, UIC Zoonosis y Enfermedades Emergentes ENZOEM, Universidad de Córdoba, Córdoba, Spain.
Unidad de Enfermedades Infecciosas, Grupo de Virología Clínica y Zoonosis, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, Córdoba, Spain.
Grupo Sanidad y Biotecnología (SaBio). Instituto de Investigación en Recursos Cinegéticos IREC (UCLM-CSIC-JCCM). Universidad de Castilla-la Mancha (UCLM), Ciudad Real, Spain.
CIBERINFEC, ISCIII - CIBER de Enfermedades Infecciosas, Instituto de Salud Carlos III, Madrid, Spain.
Grupo Sanidad y Biotecnología (SaBio). Instituto de Investigación en Recursos Cinegéticos IREC (UCLM-CSIC-JCCM). Universidad de Castilla-la Mancha (UCLM), Ciudad Real, Spain
Hepatitis E virus (HEV) is an emerging zoonotic virus of public health concern, of which pigs, wild boar and red deer are the main reservoirs. The European Food Safety Authority (EFSA) has recently prioritized the development of monitoring programs of HEV at different stages of the pig food chain, including outdoor pig farming. Pigs managed under these extensive production systems frequently share habitat and natural resources with wild boar and red deer during fattening stages and cross-species transmission of HEV among these species has previously been suggested. In this context, we aimed to (I) to evaluate the risk of HEV circulation within the production phases of extensively raised pigs and at the domestic-wildlife interface, and (II) to identify the genotypes circulating within these hosts. A total of 1452 pigs from seven different pig farms were longitudinally sampled during the breeding, rearing, and fattening production phases. In addition, 138 and 252 sympatric wild boar and red deer, respectively, were analysed. Anti-HEV antibodies were found in 1245 (85.7 %) out of the 1452 Iberian pigs sampled. The seroprevalence was 30.4 % in the breeding phase, 95.4 % in the rearing phase and 97.0 % in the fattening phase. Statistically significant differences (P < 0.05) were found among the three production phases. The seroprevalence was significantly higher (P < 0.001) in fattening pigs compared to those found in sympatric wild boar (31.9 %) and red deer (2.0 %). Three (1.0 %) out of the 293 serum pools analysed were positive for viral RNA. One of them was identified in pigs at the rearing phase (genotype 3 f) and two in wild boar (genotypes 3 f and 3 m). The high seroprevalence detected in extensively raised pigs, together with the detection of the zoonotic HEV-3 f and HEV-3 m subtypes in sympatric domestic and wild swine, highlights the risk of zoonotic transmission and the need to establish surveillance programs and control measures, particularly in breeding and rearing phase, in these epidemiological scenarios.
Hepatitis E virus exhibited increasing seroprevalence across breeding, rearing, and fattening phases of extensively raised pigs, indicating within-host population dynamics and maintenance in domestic reservoirs.
Anti-HEV antibodies were found in 1245 (85.7 %) out of the 1452 Iberian pigs sampled. The seroprevalence was 30.4 % in the breeding phase, 95.4 % in the rearing phase and 97.0 % in the fattening phase. Statistically significant differences (P < 0.05) were found among the three production phases.
Method
longitudinal sampling; serology
Sample type
serum
Geographic raw
Spain
Country inferred
Spain
Reservoir EcologyExtraction confidence 0.90
Key finding
Extensive pig farming in Spain facilitates ecological contact between pigs, wild boar, and red deer, forming a domestic–wildlife interface relevant to hepatitis E virus maintenance.
Pigs managed under these extensive production systems frequently share habitat and natural resources with wild boar and red deer during fattening stages and cross-species transmission of HEV among these species has previously been suggested.
Geographic raw
Spain
Country inferred
Spain
Reservoir EcologyExtraction confidence 0.90
Key finding
Hepatitis E virus subtypes 3f and 3m were detected in both pigs and wild boar, supporting shared reservoir circulation across domestic and wild hosts in Spain.
Three (1.0 %) out of the 293 serum pools analysed were positive for viral RNA. One of them was identified in pigs at the rearing phase (genotype 3 f) and two in wild boar (genotypes 3 f and 3 m).
Method
molecular detection
Sample type
serum
Geographic raw
Spain
Country inferred
Spain
Serological Evidence3 records
Serological EvidenceExtraction confidence 0.95
Key finding
Extensively raised Iberian pigs in Spain showed high seroprevalence of hepatitis E virus antibodies, indicating widespread viral exposure.
Anti-HEV antibodies were found in 1245 (85.7 %) out of the 1452 Iberian pigs sampled. The seroprevalence was 30.4 % in the breeding phase, 95.4 % in the rearing phase and 97.0 % in the fattening phase.
Sample type
serum
Serological EvidenceExtraction confidence 0.95
Key finding
Serological testing detected antibodies to hepatitis E virus in wild boar and red deer at lower prevalence than in pigs, suggesting cross-species exposure at the domestic-wildlife interface.
The seroprevalence was significantly higher (P < 0.001) in fattening pigs compared to those found in sympatric wild boar (31.9 %) and red deer (2.0 %).
Sample type
serum
Serological EvidenceExtraction confidence 0.95
Key finding
Serological testing showed low prevalence of hepatitis E virus antibodies in red deer cohabiting with pigs and wild boar, indicating limited exposure to HEV.
The seroprevalence was significantly higher (P < 0.001) in fattening pigs compared to those found in sympatric wild boar (31.9 %) and red deer (2.0 %).
Sample type
serum
Zoonotic Surveillance3 records
Zoonotic SurveillanceExtraction confidence 0.95
Key finding
Longitudinal surveillance in extensively raised pigs in Spain found high seroprevalence of hepatitis E virus and viral RNA of genotype 3f during the rearing phase.
A total of 1452 pigs from seven different pig farms were longitudinally sampled during the breeding, rearing, and fattening production phases. Anti-HEV antibodies were found in 1245 (85.7 %) out of the 1452 Iberian pigs sampled. Three (1.0 %) out of the 293 serum pools analysed were positive for viral RNA.
Method
serology; RNA detection
Sample type
serum
Geographic raw
Spain
Country inferred
Spain
Zoonotic SurveillanceExtraction confidence 0.95
Key finding
Serological and molecular surveillance detected hepatitis E virus genotypes 3f and 3m in wild boar cohabiting with extensively raised pigs in Spain.
In addition, 138 and 252 sympatric wild boar and red deer, respectively, were analysed. The seroprevalence was significantly higher in fattening pigs compared to those found in sympatric wild boar (31.9 %) and red deer (2.0 %). Two wild boar serum pools were positive for viral RNA (genotypes 3 f and 3 m).
Method
serology; RNA detection
Sample type
serum
Geographic raw
Spain
Country inferred
Spain
Zoonotic SurveillanceExtraction confidence 0.90
Key finding
Low seroprevalence of hepatitis E virus antibodies was observed in red deer sampled in Spain.
252 sympatric red deer were analysed. The seroprevalence was 2.0 %, indicating limited exposure to hepatitis E virus in this population.
Method
serology
Sample type
serum
Geographic raw
Spain
Country inferred
Spain
Genomic Evolution2 records
Genomic EvolutionExtraction confidence 0.70
Key finding
Hepatitis E virus genotype 3f was detected in pigs and both genotype 3f and 3m in wild boar, demonstrating evolutionary diversity and shared HEV lineages between domestic and wild hosts.
Three (1.0 %) out of the 293 serum pools analysed were positive for viral RNA. One of them was identified in pigs at the rearing phase (genotype 3 f) and two in wild boar (genotypes 3 f and 3 m).
Genes or proteins
viral RNA; whole genome
Analysis methods
genotyping
Genomic EvolutionExtraction confidence 0.70
Key finding
Wild boar carried hepatitis E virus genotypes 3f and 3m, showing multiple viral subtypes circulating in wild suids related to domestic pig strains.
Cross Species TransmissionExtraction confidence 0.80
Key finding
Detection of the same hepatitis E virus genotypes (3 f and 3 m) in both domestic pigs and wild boar indicates possible animal-to-animal cross-species transmission in Spain.
Pigs managed under these extensive production systems frequently share habitat and natural resources with wild boar and red deer during fattening stages and cross-species transmission of HEV among these species has previously been suggested... One of them was identified in pigs (genotype 3 f) and two in wild boar (genotypes 3 f and 3 m).
