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Hepatitis E virus control in the pig reservoir Wim H. M. van der Poel June 2018 © Wageningen University
Hepatitis E virus control in the pig reservoir
Wim H. M. van der Poel
June 2018
© Wageningen University
Wageningen Bioveterinary Research
Wageningen University campusWageningen
Wageningen BioVeterinary ResearchLelystad
Presentation outline
• Introduction
• Hepatitis E disease impact
• Swine reservoirs
• Foodborne transmission
• Direct exposure from swine
• HEV prevention and control
© Wageningen University
Hepatitis E virus
Symptoms: fever, jaundice, hepatitis, hepatomegaly, anorexia, malaise, nausea, vomiting
Overall case-fatality rate: 1%-4%
Fam. Hepeviridae
ssRNA, three ORFs
Non-enveloped virus, 7-34 nm
Cell culture propagation difficult
© Wageningen University
Hepatitis E virus 2017
Increasing HEV incidences in Europe
Increasing HEV RT-PCR detections in foods
● Liver sausage, paté
HEV infection associated with neural disorders (Dalton et al., 2016)
Guillain-Barré syndrome and neuralgic amyotrophy are associated with locally acquired HEV in approximately 5 and 10% of the cases
© Wageningen University
Hepatitis E in the Netherlands
Prevalence and disease estimates
>100 hospital treatments per year
>20 serious acute clinical infections per year
>300 cases in immunocompromised per year
1-3% of solid organs transplant patients developchronic hepatitis E
HEV seroprevalence >10%
> 20000 infections per year
Hepatitis E virus infection notifications
The Netherlands (cumulative)
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Hepatitis E virus genotype 3
subtypes and phylotypes in humans and swine
The Netherlands 2010-2015
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Hogema et al., 2018
Food and environmental routes of hepatitis E
virus transmission
Van der Poel, 2013
© Wageningen University
Hepatitis E
virus
reservoirs
and hosts
Hepatitis E virus taxonomy
and predominant hosts
Orthohepevirus A
• Genotype 1 and 2 human
• Genotype 3 human, swine, deer
• Genotype 4 human, swine, deer
• Genotype 5 and 6 wild boar
Orthohepevirus B chicken
Orthohepevirus C rat, ferret, mink
Orthohepevirus D bats
Piscihepevirus A cutthroat trout
Smith et al., 2014
Hepatitis E virus seroprevalences
domestic swine and wild boar EuropeCountry seroprevalence Reference
Netherlands 73% (803/1100) Van der Poel et al., 2014
France 31% (2035 /6565) Rose et al., 2011
Germany 65% (216/332) Dremsek et al., 2013
United Kingdom 93% (584/629) Grierson et al., 2015
Belgium 73% (613/840) Thiry et al., 2014
Spain 20% (233/1141) Jimenez de Oya et al., 2011
Ireland 27% (89/330) O’Connor et al., 2015
Switzerland 58% (1161/2001) Burri et al., 2014
© Wageningen University
Country seroprevalence Reference
Netherlands 18% (29/164) Van der Poel 2016 (in prep.)
France (Corse) 26% (62/284) Jori et al. 20116
Germany (Saxony-A) 33% (109/330) Denzin et al., 2013
United Kingdom Not reported
Belgium 34% (130/383) Thiry et al., 2015
Italy 1,6% (3/196) Di Profio et al., 2016
Spain 43% (63/150) De Deus et al., 2008
Slovenia 30.2% (87/288) Zele et al., 2016
Geographical distribution
zoonotic hepatitis E viruses in swine
Genotype 3
Genotype 4© Wageningen University
HEV transmission in domestic pigs
(Bouwknegt et al., 2008)Inoculated
Animal (IC)1st contact
animal
(C1)
2nd contact
animal
(C2)
3rd contact
animal
(C3)
Box 1
Box 2
Box 3
T1
T2
•1-to-1 Experiment• 40 spf-piglets• HEV Gt3 isolate• Fecalsamples• serum samples
• Infectivity period 29.7 days;
• R0 = 10.7 (7.0-16.3)
• Conclusions:• HEV will cause large
outbreaks• Pigs are true reservoir
of HEV Gt3
HEV antibody prevalence
(Bouwknegt et al., 2008)
• More exposure, higher seroprevalence
• Difference between swine vets and GP
• Large credibility intervals
0%
5%
10%
15%
20%
25%
30%
35%
40%
Sw ine veterinarians Non-sw ine
veterinarians
General population
Ser
opre
vale
nce
Non-inf Inf. Sp. Inf. Se Inf. SE en SP
Other routes of Hepatitis E virus transmission
Blood donation, Blood products
Solid organ transplantation
Intravenous drug use
Pharmaceuticals of swine origin (i.e. heparin, pancreatin)
Xenotransplantation (i.e. heart valves pancreas cells, liver cells)
Crossan et al., 2013; Hewitt et al., 2014; Pas et al.,
2012; Christensen et al., 2002; Denner 2015
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HEV in byproducts and sausages
Hemaglobin
Spray dried porcine plasma (SDPP)
Fibrinogen
Blood/plasma
RT-PCR detections
1-4 * 10E copies/gram
Boxman et al., 2017
Said et al., 2017
Hulst et al., 2017
EFSA., 2017
Spray dried porcine plasma (SDPP)
By-product of pork production.
High quality proteins of porcine origin
Used in food industry (‘filler’)
Common in starter diets of weaned
piglets and in pet foods
Has been associated with spread of
porcine viruses
Virus sequences detected in SPDD
product
Viable (infectious) virus may be present
in SPDD
© Wageningen University
Hulst et al., 2017
Spray drying process porcine plasma
© Wageningen University
Experimental spray-drying (Büchie)
Porcine serum substrates spiked with prototype viruses
Testing of virus reductions (PCR and cell culture)
Conclusion: High pH (>9.8) and preceding heat treatment indicated to inactivate viruses.
© Wageningen University
Hulst et al., 2017
Hepatis E virus in pork sold in the UK
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“I call it the Brexit virus. It attacks the liver and nerves, with a peak in May”
Dr Harry Dalton
Sunday Express, May 2017
Daily Express, May 2017
Import and export of pork in The United Kingdom
Imported pork for consumption
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Sources: BPEX and ADHBpork (UK), CBS (NL), SEGES (DK), Agreste Conjuncture (Fr), VLAM (Be), Comtrade, Central Statistics Office, FAMMU/FAPA and MRIRW/ZSRIR (Pl), BLE and BMEL (De).
Countries where pork is imported from
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Pork consumption
Country
Main countries where pork is imported from
Belgium 1) Netherlands, 2) Germany, 3) France
Denmark 1) Germany, 2) Poland, 3) Netherlands
France 1) Spain, 2) Germany, 3) Belgium
Germany 1) Netherlands, 2) Belgium, 3) Denmark
United Kingdom 1) Denmark, 2) Netherlands, 3) Germany
Netherlands 1) Germany, 2) Belgium, 3) United Kingdom
Poland 1) Belgium, 2) Germany, 3) Denmark
Sources: BPEX (UK), CBS(NL), COMTRADE (Pl), AHDBpork (UK), Danish Agriculture and Food Council (DK), Agreste Conjuncture (Fr), vlam (Be), Central Statistics Office (Po) FAMMU/FAPA, based on data from MRIRW/ZSRIR (Po)
Table 2. Countries where fresh or frozen pork for consumption is imported from
Hepatitis E virus characterizations in swine
Obtained number of ORF2 sequences 2016
Table1. Numbers of Hepatitis E virus ORF2 sequences from swine and human samples collected in 2016 as provided by the participating countries
Country Porcine ORF2 sequences
Human ORF2 sequences
Total ORF2 sequences
Belgium 2 47 49
Denmark 13 4 4
France 8 16 24
Germany 1 11 12
United Kingdom 18 21 39
Netherlands 12 10 22
Poland 21 0 21
Total 75 109 171
HEV phylogeny human and swine sequences
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Screening ‘high health’ swine farms
Netherlands 2015
Herd(3-6 months oldfattening pigs)
Ab-pos(ElisaVan der Poel et al., 2014)
PrevalenceEstimate
A 10/10 100%
B 11/11 100%
C 9/10 90%
D 8/12 67%
E 12/12 100%
HEV detections (RT-PCR) in swine farms
Location Type of sample HEV positives
Inside farm building Feces, surface
swabs
5/149 (3%)
Outside farm
building
Silo surroundings;
trucks’ routes; feces
on outside dock
11/101 (11%)
Trucks Mudguard; carpet;
trailer
4/98 (4%)
Slaughterhouse yard Trucks’routes; utility
vehicle
12/104 (12%)
Nantel-Fortier et al., 2015
© Wageningen University
Hepatitis E virus inactivation
• Stable in water environment; also in blood
• No complete inactivation between 45 and 70C (Emerson et al., 2005)
• Inactivation:
• Chlorine (Girones et al 2014)
• Heating >71 C ( Barnaud et al., 2012); >70 C, 5 min (Imagawa etal 2018)
• UV (Cook and VanderPoel 2015)
• Studies hampered by the fact that there is not an easy HEV cell culture propagation method available and no appropriate surrogate
© Wageningen University
Hepatitis E Vaccine
Recombinant hepatitis E vaccine, HEV 239
Purified amino acids 368-606 of capsid protein (HEV gt1 ORF2) expressed in E. coli.
Xiamen Innovax Biotech, Xiamen China.
Heterologous protection against gt3 and gt4 unsure
© Wageningen University
HEV prevalence profiles
(assuming global transmission)Backer et al., 2012
maesuredestimated
Pigs 0-25 weeks of age
Plots of 10 herds
© Wageningen University
Effect of vaccination
Animals vaccinated before entering herd
Fraction of infectious animals at slaughter age
If reduction below 75%, better to delay vaccination
Backer et al., 2012
© Wageningen University
Global One Health
“Global one health is the combined effort of multipledisciplines to improve health of humans, animals andplants within sustainable ecosystems by using anintegrated systems approach to come to transnationalsolutions”.
“Global One Health – a new integrated approach” by Fresco L.O. et al. 2015,published by the Trilateral Commission.
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Increasing public health risk of HEV in the
developed world
• Aging population
• Increasing number of blood transfusions and
organ transplants
• increasing number of immunocompromised
individuals /receiving immunosuppressive
treatment
• Increasing consumption of pork and related
products
• More virulent HEV strains
Conclusions
• Increasing impact of HEV infections
• Swine are the main reservoir of zoonotic HEVs worldwide
• Foodborne infection likely to be the main transmission route
• Very stable HEV reservoir in swine, vaccination will be needed
to reduce HEV in swine
• HEV control needed at multiple points along the food chain
• One-Health approach needed to combat hepatitis E
© Wageningen University
Renate Hakze (WBVR)
Jantien Backer (WBVR)
Nicole Pavio (ANSES)
Ana Maria de Roda Husman
Saskia Rutjes (RIVM)
Martijn Bouwknegt (RIVM)
Mart de Jong (WUR)
Nigel Cook (FERA)
Hans Zaaijer (Sanquin)
Boris Hogema (Sanquin)
Rosina Girones (UB)
Acknowledgements
Lars Larsen (DTU-VET)
Jesper Skag Krog (DTU-VET)
Ilaria di Bartolo (ISS)
Malcolm Banks (APHA)
Alessandra Berto (WBVR)
Els van Coillie (ILVO)
Edmilson Oliviera de Filho (UdL)
Frank Harders (WBVR)
Vanessa Suin (WIV-ISP)
Artur Rzezutka (LVRI)
Bhudipa Choudhury (APHA)
