Date post: | 22-Jan-2018 |
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Hepatitis E surveillance in Sweden
Lena SundqvistECDC, Stockholm9-10 December 2015
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National surveillance
Case definition
Suspected case: Clinical illness compatible with the diagnosis and an
epidemiological link
Confirmed case: A laboratory-confirmed case
Laboratory criteria for diagnosis (at least one of the following conditions):
• detection of hepatitis E virusspecific antibody-respons in serum indicating current
infection
• detection of hepatitis E virus RNA in serum or faeces
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• A legally notifiable disease in Sweden since 1993.
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Notification
• Suspected and laboratory confirmed cases are reported by clinicians and the diagnostic laboratory to a national surveillance database, SmiNet, hosted by the Public Health Agency of Sweden.
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SmiNet
Clinician Laboratory
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Data collected in SmiNet
Clinical notification
Demographic and epidemiological data
Unique patient number, age, sex
Date and responsible county for notification
Type of infection, onset of disease, related cases
Country of infection, travel history, source of infection
Occupation
Specific instructions and recommendations
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Laboratory notification
Sample material: serum, faeces
Date of sampling
Diagnostic method: antibody-detection
nucleic acid-detection
antigen-detection
Results: anti-HEV IgM
anti-HEV IgG/IgM
HEV-RNA
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Contact tracing
• 21 counties
• The County Medical Officer is responsible for contacting notified cases of hepatitis E to collectadditional information on possible routes of transmission.
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Laboratory diagnostics
Department of clinical Microbiology at Sahlgrenska University Hospital, Gothenburg.
Diagnostic methods
ELISA (IgM/IgG)
RT-PCR
Molecular typing
Sequencing is routinely performed on all confirmed positive samples
HEV test on blood samples is only performed if requested by the reffering clinician.
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0
0.1
0.2
0.3
0.4
0
5
10
15
20
25
30
Nu
mb
ero
fca
ses
Notified cases of hepatitis E in Sweden1997-1 dec 2015 (n=173)
Travel-related cases Domestic cases Incidence
Data available in SmiNet since 1997
Inci
dence
(inc/
100 0
00)
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0
10
20
30
40
50
60
70
80
90
Female Male
Pro
port
ion o
fca
ses
(%)
Travel-related cases Domestic cases
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0
5
10
15
20
25
30
35
0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-90
Pro
port
ion o
fca
ses
(%)
Age group
Travel-related cases Domestic cases
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0
10
20
30
40
50
60
Food Food/water Water Unknown
Num
ber
of
case
s
Travel-related cases Domestic cases
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Studies on hepatitis E in Sweden
Humans The seroprevalence of anti-HEV antibodies in the general population is
6-9% and in pig farmers 13%. (Sylvan et al, Olsen et al)
HEV RNA has been detected in 57% of anti-HEV-positive samples
(22% were from patients with detectable anti-HEV IgG only) (Widén et al)
HEV RNA has been detected in 1:8000 plasma donations. (Baylis et al)
The first case of chronic hepatitis E infection in a heart transplant
recipient in Sweden has been identified. (Waldenström et al)
13% of Swedish lungtransplant recipients had anti-HEV IgG one year
after lung transplantation. HEV RNA could not be detected. (Magnusson et al)
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Animals
HEV could be detected in 30% of the pigs from 22 pig farmsand in 8% of the wild boars from nine counties. (Widén et al)
Genotype 3 strains from pigs and wild boars show close relatedness between strains from piglets from thesame farm and from wild boars from the same county.
Genotype 3 strains from humans show relatedness withstrains from pigs and wild boars from the same county.
30% of Swedish moose have markers of activeand past infection and 15% are positive for HEV RNA.The HEV genome is 35-60% identical to existing HEVsbelonging to the genotype 1-6 group. (Lin et al)
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Environment
Sewage samples were investigated for the presence of different
pathogenic viruses as a method to detect upcoming outbreaks and to
provide an early warning. (Hellmér et al)
HEV was detected at a constant low concentration in sewage samples
indicating that HEV circulated in the population during the study period.
Thank you for your attention!