Indigenous hepatitis E virus infection in England and Wales

Editor—Palmer et al undertook a qualitative risk assessment of the emerging zoonotic potential of porcine hepatitis E virus (HEV).¹ They recommended enhanced surveillance of non-A, non-B, non-C hepatitis after noting that sporadic cases of HEV may be missed in humans as testing is not routine in the UK without a history of foreign travel.

We investigated cases of HEV in England and Wales to describe the epidemiology and study possible risk factors for the acquisition of indigenous infection. Between 1 January 2005 and 30 June 2005 the Health Protection Agency HEV reference laboratories confirmed 181 cases of acute hepatitis E, including five deaths in patients with underlying serious medical conditions. Travel to an endemic area was recorded for 69 cases, so further enquiries were made into the remaining 112 cases with an unknown travel history.

Twenty five (14%) patients had not travelled outside the United Kingdom in nine weeks before their illness and of these 20 (80%) were male and the median age was 59 years (interquartile range 43 to 71.5 years). Ten of these cases were polymerase chain reaction positive, all but one were HEV genotype 3 (North American and European genotype). Twenty four of the 25 patients had non-South Asian names. On the basis of HEV genotype 3 and demographic information (age within interquartile range and non-South Asian name), an additional 23 patients for whom the travel history is unknown were likely to have acquired their infection in the UK. Twenty two non-travel associated case patients were interviewed by using a detailed trawling questionnaire. Despite the striking demographic finding that the majority of cases were middle aged to elderly white men, no common source, including contact with pigs or pig food products, has so far been identified by our study.

The total number of cases reported in the first six months of 2005 was three times that expected on the basis of routine voluntary surveillance, and the proportion of non-travel associated cases was much larger than that previously reported.² With the evolving epidemiology of HEV in England and Wales, HEV should be considered as an aetiological agent of acute and fulminant hepatitis in patients reporting no travel history. We therefore need to raise awareness among health professionals of the requirement for further investigation of non-travel associated cases of non-A, non-B, non-C hepatitis and standardise laboratory and hospital referral procedures.