Prevalence of HEV in finishing pigs; cross-sectional exploration of farm specific patterns and evaluation of sampling

This work presents results of pilot projects needed for the field studies in OH-EJP BioPigEE and the Dutch project on Hepatitis E in pig farms.

Accepted Abstract:

Aim: to assess prevalence of HEV in pigs from different age groups and determine sensitivity and specificity of pen level sampling methods

Methods: two cross-sectional pilot studies were conducted.

I) On Farms A-D (farrow-finish farms); individual rectal swab samples (RS) were taken at ~5, 9, 12 and 24 weeks of age, originating from 7 pens per age group per farm (≤140 per group, Ntotal=1704 RS).

II) On Farm E, 7 pens with pigs of 14, 16, 18 and 24 weeks were sampled. Besides RS, boot sock samples (BS), chewing rope (S) and fresh faecal droppings (FD) were collected.

All samples were analysed by PCR. RS were first pooled per pen (RSp) and tested individually for positively tested pools. Bayesian latent class analysis (BLCA) was used to assess Sensitivity and Specificity for sampling methods (II).

Results:

I) On Farm A, HEV was not found. On farms B-D, 24weeks pigs tested positive, all others negative. Within pen prevalence ranged 0-0.89.

II) On farm E, at 14 weeks 3/7 pens tested positive by FD, 3/7 by S, 2/7 by RS and 6/7 by BS. At 16 and 18 weeks all pen level samples tested positive for all pens. At 24 weeks, FD and RS tested negative. BCLA indicates Se for all tests to be ~0.94, but Specificity varied (Sp-BS=0.22 , Sp-S=0.71, Sp-FD=0.86 and Sp-RSp=0.93).

Conclusions:

HEV infection patterns were farm specific. Boot socks are useful for detection of early or intermittent shedding. Fecal droppings are adequate for non-invasive HEV testing on pen level.

Funding:

This work was part of the project “HEVentie: hepatitis E virus intervention in primary pig production”. HEVentie receives financial support from the Topsector Agri&Food (TKI AF-18119). Within TKI Agri&Food private partners, research institutes and government cooperate to innovations for safe and healthy food for 9 billion people on a resilient globe. This work was supported by funding from the European Union’s Horizon 2020 Research and Innovation programme under grant agreement No 773830: One Health European Joint Programme. All students participating in sampling and lab work are greatly acknowledged.