Outbreak of hepatitis A infection associated with the consumption of frozen berries, Ireland, 2013 - linked to an international outbreak

M Fitzgerald; L Thornton; J O'Gorman; L O’Connor; P Garvey; M Boland; A M Part; J Rogalska; H Coughlan; J MacDiarmada; J Heslin; M Canny; P Finnegan; J Moran; D O’Flanagan; Collective on behalf of the Hepatitis A Outbreak Control Team

doi:10.2807/1560-7917.ES2014.19.43.20942

Surveillance and outbreak reports Open Access

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Outbreak of hepatitis A infection associated with the consumption of frozen berries, Ireland, 2013 - linked to an international outbreak
M Fitzgerald^1,2 , L Thornton¹ , J O'Gorman³ , L O’Connor⁴ , P Garvey¹ , M Boland⁵ , A M Part⁶ , J Rogalska^1,2 , H Coughlan⁷ , J MacDiarmada⁵ , J Heslin⁸ , M Canny⁹ , P Finnegan¹⁰ , J Moran^1,3 , D O’Flanagan¹ , Collective on behalf of the Hepatitis A Outbreak Control Team¹¹
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Affiliations: ¹ Health Service Executive (HSE) - Health Protection Surveillance Centre (HPSC), Dublin, Ireland ² European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden ³ National Virus Reference Laboratory (NVRL), University College Dublin, Dublin, Ireland ⁴ Food Safety Authority of Ireland (FSAI), Dublin, Ireland ⁵ Department of Public Health, HSE East, Dublin, Ireland ⁶ Environmental Health Service, HSE Dublin Mid-Leinster Region, Dublin, Ireland ⁷ Department of Public Health, HSE South, Cork, Ireland ⁸ Department of Public Health, HSE South-East, Kilkenny, Ireland ⁹ Department of Public Health, HSE West, Galway, Ireland ¹⁰ Department of Public Health, HSE North-East, Meath, Ireland ¹¹ The members of the Outbreak Control Team are listed at the end of the article

Correspondence:
M Fitzgerald
margareta.fitzgerald hse.ie
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Citation style for this article: Fitzgerald M, Thornton L, O'Gorman J, O’Connor L, Garvey P, Boland M, Part A M, Rogalska J, Coughlan H, MacDiarmada J, Heslin J, Canny M, Finnegan P, Moran J, O’Flanagan D, on behalf of the Hepatitis A Outbreak Control Team Collective. Outbreak of hepatitis A infection associated with the consumption of frozen berries, Ireland, 2013 - linked to an international outbreak. Euro Surveill. 2014;19(43):pii=20942. https://doi.org/10.2807/1560-7917.ES2014.19.43.20942 Received: 20 Feb 2014

Abstract

In May 2013, a European alert was issued regarding a hepatitis A virus (HAV) outbreak in Italy. In June 2013, HAV subgenotype IA with an identical sequence was identified in Ireland in three cases who had not travelled to Italy. The investigation consisted of descriptive epidemiology, a case-control study, microbiological testing of human and food specimens, molecular typing of positive specimens and food traceback. We identified 21 outbreak cases (14 confirmed primary cases) with symptom onset between 31 January and 11 October 2013. For the case-control study, we recruited 11 confirmed primary cases and 42 matched controls. Cases were more likely than controls to have eaten berry cheesecake (matched odds ratio (mOR):?12; 95% confidence interval (CI):?1.3-114), whole frozen berries (mOR: 9.5; 95% CI: 1.0-89), yoghurt containing frozen berries (mOR:?6.6, 95% CI:?1.2-37) or raw celery (mOR:?4; 95% CI: 1.2-16). Among cases, 91% had consumed at least one of four products containing frozen berries (mOR:?12; 95% CI: 1.5-94). Sixteen food samples tested were all negative for HAV. As products containing frozen berries were implicated in the outbreak, the public were advised to heat-treat frozen berries before consumption. .