Practice

Identifying a hepatitis B outbreak by molecular surveillance: a case study

BMJ 2006; 332 doi: https://doi.org/10.1136/bmj.332.7537.343 (Published 09 February 2006) Cite this as: BMJ 2006;332:343
  1. N Fisker, senior registrar (niels.fisker@dadlnet.dk)1,
  2. N L T Carlsen, consultant,
  3. H J Kolmos, professor4,
  4. L Tønning-Sørensen, laboratory technician2,
  5. A Høst, associate professor3,
  6. P B Christensen, senior registrar
  1. 1 Departments of Clinical Immunology and Paediatrics, Odense University Hospital, Sdr Boulevard 29, DK-5000 Odense C, Denmark
  2. 2 Department of Paediatrics, Odense University Hospital
  3. 3 Department of Clinical Microbiology, Odense University Hospital
  4. 4 Department of Internal Medicine, Section of Infectious Diseases, Odense University Hospital
  1. Correspondence to: N Fisker

    Infection outbreaks are usually recognised when an unexpectedly high number of cases of a clinical illness are observed. With hepatitis B infection, the incubation period is long and a substantial proportion of infected people—especially children and the immunocompromised host—may remain asymptomatic.13 These factors increase the risk of prolonged and unrecognised outbreaks. Denmark has not implemented universal childhood hepatitis B immunisation, and vaccination is not required for health workers performing invasive procedures.

    Phylogenetic analysis of hepatitis B virus have been used to investigate recognised outbreaks,4 5 to reject or confirm suspected chains of transmission,6 and to prove unusual reservoirs or routes of infection.7 8 We present the unravelling of an outbreak of asymptomatic hepatitis B on a paediatric ward after the incidental identification of a single case of hepatitis B. The recognition and subsequent halting of the spread of this outbreak were possible owing to the availability of a DNA sequences library compiled from patients with hepatitis B in the locality.9

    Case description

    During preparation for bone marrow transplantation, a child was diagnosed with an acute asymptomatic hepatitis B infection at the paediatric haematology and oncology department at Odense University Hospital. Screening for hepatitis B had been negative two years previously, and serology testing and polymerase chain reaction in repository blood donation samples and follow-up samples from all involved blood donors were negative for the virus. The patient had had no contact with known hepatitis B cases during the suspected incubation period.

    As part of a research programme, strains of the hepatitis B virus consecutively detected in the area had been partially sequenced. The patient's sequence (the hepatitis B epi strain) was identical to that of a known hepatitis B carrier who had been …

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