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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Notified cases of hepatitis E in Sweden1997-1 dec 2015 (n=173)

Travel-related cases Domestic cases Incidence

Data available in SmiNet since 1997

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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!