A Cluster of Hepatitis A Viral Infection in HSE South 

HA Ferris, A Dillon, MB O’ Sullivan

Department of Public Health, HSE South, Cork.

Abstract

Hepatitis A is an acute viral infection of the liver that produces clinical features ranging from asymptomatic infection to fulminant hepatitis1. The authors report a cluster of 5 serologically-confirmed cases of acute Hepatitis A Virus (HAV), all serum IgM positive for HAV Genotype 1A. This is on a background of only 2 other cases notified to HSE-South in 2016 to date, both travel related. There was a considerable delay in notification in two out of 5 cases. This case report highlights the importance of prompt notification of Hepatitis A, as timely notification would have facilitated prompt contact vaccination and might well have prevented illness in two subsequent household contacts.

Introduction
Hepatitis A is an acute infection of the liver cause by the Hepatitis A virus, a single stranded RNA virus. Ireland has a low incidence of Hepatitis A with an average of 31 cases annually 2011-20152. The most common symptoms are jaundice, fever and abdominal pain; however, children are often asymptomatic. The virus spreads primarily via the fecal oral route. The highest period of infectivity is from two weeks before the onset of jaundice until one week after3. Although Ireland is a low incidence country, it is of public health importance due to its outbreak potential and ability to cause severe prolonged disease.

 Case Report
Case 1 was a symptomatic 10 year old child and was notified to HSE South in August 2016. Notification was delayed by almost two weeks. The child had been admitted to hospital 2 weeks previously for investigation of jaundice, anorexia and vomiting. There was no known contact with a case of Hepatitis A. Case 2 was notified 3 days after Case 1 and was a symptomatic 10 year old child. Both Case 1 and 2 attended the same primary school but were in different classes and did not socialise outside of school. Case 3 and 4 were parents of the index case and were linked via intra-familial spread. Case 5 was a symptomatic 13 year old school girl who attended a secondary school in a different geographical location. A potential link between Case 1 and Case 5 was identified via a visit to a swimming pool with suboptimal chlorine levels. Notification of this case was delayed by 18 days.

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Discussion
Following notification of the index case, epidemiological, environmental and microbiological investigations were conducted (Figure No.1). Further exploration revealed that Case 1, 3 and 4 were linked epidemiologically through intra-familial spread. Case 1 and 2, although not in the same class nor friends outside of school, attended the same school trip in June 2016. Swimming pool attendance in early July 2016 was the only ascertainable link between Case 1 and 5. National guidelines recommend that the Hepatitis A vaccine is administered to close contacts within two weeks of exposure4. However, the contacts of Cases 1 and 5 were outside the window of vaccination due to delayed notification.

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This case report illustrates the Public Health consequences of delayed notification. Timely notification would have facilitated prompt contact vaccination and may have prevented illness in subsequent contacts. Improved communication with clinicians and laboratory staff should improve the speed of notification in the future.

Correspondence:
HA Ferris, SpR Public Health Medicine,
Department of Public Health, Floor 2 Block 8,
St Finbar’s Hospital, Cork.
Email: Helena.ferris@hse.ie,

Conflict of Interest:
There are no conflicts of interest.

References

1 Lewis G, Sheringham J, Lopez Bernal J, Crayford T. Mastering Public Health: a Guide to Examinations and Revalidation.CRC press, 2nd edition. 2015, p300.
2 Health Protection Surveillance Centre (HPSC). Annual Report 2014. Available at:
http://www.hpsc.ie/AboutHPSC/AnnualReports/File,15505,en.pdf
3 Health Protection Surveillance Centre (HPSC). Hepatitis A Factsheet. Available at:https://www.hpsc.ie/A-Z/Gastroenteric/GastroenteritisorIID/Guidance/IIDPublicHealthandClinicalGuidancediseasespecificchapters/File,13517,en.pdf
4 National Immunisation Guidelines; Hepatitis A. August 2015. Available at: http://www.hse.ie/eng/health/immunisation/hcpinfo/guidelines/CH8_Hepatitis_A.pdf

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