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Indigenous HEV infection in the UK: a hazard for blood donation?. Samreen Ijaz Virus Reference Department Health Protection Agency. Female. 50-59 yrs. Genotype 3 UK strains. >60 yrs. Male. Genotype 1& 2 Endemic strains. GENDER. AGE. MOLECULAR ANALYSIS.

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samreen ijaz virus reference department health protection agency

Indigenous HEV infection in the UK: a hazard for blood donation?

Samreen Ijaz

Virus Reference Department

Health Protection Agency

hev infections in england and wales 2005 study

Female

50-59 yrs

Genotype 3

UK strains

>60 yrs

Male

Genotype 1& 2

Endemic

strains

GENDER

AGE

MOLECULAR ANALYSIS

HEV Infections in England and Wales (2005 study)

HEV seropositive samples with no travel history identified from 1996-2003 at CPHL

hev seroprevalence in england year 1991

40%

1991

35%

30%

25%

Prevalence

20%

15%

10%

5%

0%

1-9

10-19

20-29

30-39

40-49

50-59

60-69

70-79

Age group (years)

HEV seroprevalence in England(year 1991)
hev prevalence by age group 1991 vs 2004

40%

1991

2004

35%

30%

25%

Prevalence

20%

15%

10%

5%

0%

1-9

10-19

20-29

30-39

40-49

50-59

60-69

70-79

Age group (years)

HEV prevalence by age-group1991 vs 2004

Temporal shift

seroprevalence rates vs clinical disease
Seroprevalence rates vs clinical disease
  • 13% seroprevalence high compared to the low rate of clinically evident disease
  • Incidence estimates between 1991 and 2004 indicate that ~62 000 cases of HEV occurred per year
  • Mathematical modelling suggests that incidence does not vary with age group
      • Shared risk factors common to all age groups
indigenous hev in england and wales
Indigenous HEV in England and Wales
  • Routes of transmission in the non-travellers could not be ascertained from this study
  • Specific risk factors for acquiring indigenous HEV infections currently remains undefined
  • The detection of HEV Abs and RNA in swine and subsequently in several other animals has led to suggestions of a potential zoonosis with animals acting as reservoirs for HEV infection in humans
      • 85% of UK pigs are anti-HEV pos.
  • Recommended that indigenous HEV be considered a level 2 zoonosis (potential zoonosis), thus requiring enhanced surveillance in the UK
parenteral transmission of hev
Parenteral transmission of HEV?
  • Higher HEV Ab levels reported in:
    • paid blood donors positive for other blood borne viruses
    • repeatedly transfused haemodialysis patients
  • Subsequent reports of transfusion transmitted HEV from France, Japan and Saudi Arabia
  • Studies from Japan have demonstrated that a small but significant proportion of their blood donors were viraemic and potentially able to cause transfusion-associated HEV
    • in the absence of elevated ALT and signs or symptoms of hepatitis
  • When characterised, the strains involved in the cases from Japan were shown to be indigenous viruses
post transfusion hepatitis in the uk
Post transfusion hepatitis in the UK
  • UK blood donor:
    • 14 days after his donation he became ill with a ‘flu-like’ illness
    • 10 days later he became jaundiced
  • Blood donor reported illness to the blood service but components of his donation had already been used
  • Testing for viral markers
    • HAV, HBV, HCV, CMV and EBV negative
    • HEV IgM and IgG positive
    • HEV RNA positive – genotype 3
post transfusion hepatitis in the uk1
Post transfusion hepatitis in the UK

Blood Donation

platelets

red cells

Pool from 4 donors which

is resuspended using plasma

from one of the donors

(not the HEV pos donor)

Would contain 20-30mls

of the donor’s plasma

Patient 2

Patient 1

INFECTED

UNINFECTED

  • HEV infection in the recipient related to dose?
post transfusion hepatitis
Post-transfusion hepatitis
  • Post transfusion hepatitis in the UK is now a relatively rare event with enhanced surveillance through the Serious Hazards of Transfusion (SHOT) reporting system
  • Approximately 62 000 cases occur each year
  • Suggests that there are a significant number of subclinical HEV infection
  • Current screening policy in the UK does not include HEV testing
  • Should we worry?
initial studies to look at uk blood donors
Initial studies to look at UK blood donors
  • HEV IgG testing on:
    • 262 samples from ‘ordinary’ blood donors
    • 339 samples from donors with a history of jaundice (all anti-HBc negative)

25

20

15

%

10

5

0

17 - 29

30 - 39

40 - 49

50 - 59

> 60

Age (yrs)

hev seroprevalence in uk blood donors
HEV seroprevalence in UK blood donors
  • HEV seroprevalence trend similar in blood donors to general population
  • Similar seroprevalence rates between ordinary and jaundice history donors
    • HEV unlikely to be responsible for donors reporting history of jaundice
    • History of jaundice not accurate screening method for excluding at risk donors
  • Further HEV IgM & RNA testing carried out on all donors
    • 4 HEV IgM pos
    • 0 HEV RNA pos

EVIDENCE OF RECENT HEV INFECTION IN DONOR POPULATION

further work
Further work
  • Evidence of seroconversion in the blood donor panel
  • Evidence of HEV RNA in minipools
  • Concern of post transfusion hepatitis in transplant recipients and the immunosuppressed
acknowledgements
Acknowledgements
  • Richard Tedder
  • Mathew Beale
  • Kate Tettmar
  • Roger Eglin
  • NHS Blood and Transplant