Background Identifying pig farms infected with hepatitis E virus (HEV) is a key aspect to implement surveillance programmes for this emerging zoonotic agent. Detection of HEV in blood has several drawbacks, including animal handling, economic costs and animal stress. The objective of this study was to evaluate the effectiveness of a non-invasive screening approach for determining the HEV status of pig farms under different management systems.
Methods Forty stool samples randomly collected from the pen floor of 17 intensive pig farms and the yard of nine extensive ones were tested for HEV RNA. The invasive method used to confirm the HEV status of the farm was HEV RNA analysis of serum samples randomly collected from 40 animals on each farm.
Results Twenty-one HEV-positive farms were detected by invasive and non-invasive methods. No positive serum or stool samples were detected on five intensive farms. A high intertest agreement (K=1; P<0.00001) was observed between both methodologies, showing the stool screening approach a 100 per cent of sensitivity and specificity with respect to the invasive method. Likewise, a significant negative relationship was observed between the HEV within-farm prevalence and the number of the first HEV-positive stool sample found (Spearman’s rho=−0.64; P=0.0004). This negative relationship was higher in intensively managed farms.
Conclusion This non-invasive screening approach could be reliably applied in a large-scale surveillance programme for determining the HEV status of pig farms under different management systems.
- differently managed pig farms
- floor collected stool
- sequential real-time PCR
- hepatitis E
- non-invasive method
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Funding This work was supported by the Ministry of Economy and Competitiveness (RD12/0017/0012) integrated in the National R+D+i Plan and cofinanced by the European Regional Development Fund and the Health Research Fund from the Institute of Health Carlos III (ISCIII) (PI16/01297), and the Spanish AIDS Research Network RD16/0025/0034-ISCIII-FEDER. AR-J is the recipient of a Miguel Servet Research Contract (CP18/00111) and MF is the recipient of a Sara Borrell Research Contract programme (CD18/00091), both from the Ministry of Science, Innovation, and Universities of Spain. JCG is supported by the FPU grant (FPU17/01319) of the Spanish Ministry of Education, Culture and Sport.
Competing interests None declared.
Ethics approval This study did not involve purposeful handling of animals, and the blood samples were not collected specifically for this study, taking advantage of samples obtained by government veterinarians for the surveillance programme of pigs of the Regional Government of Andalusia. Therefore, no ethical approval was deemed necessary for this study. Protocols, amendments and other resources were done according to the guidelines approved by the Regional Government of Andalusia following RD 53/2013 of the Ministry of Presidency of Spain, which establishes the rules for the protection of animals used in research.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request.
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