Hepatitis E

 

Hepatitis E is an infection of the liver caused by the hepatitis E virus (HEV). Historically, cases occurring in the UK have been associated with travel to countries where it commonly occurs in the population of regions where sanitation may be poor, such as parts of Asia, Africa and Central America. However, recently there has been an increase of cases in industrialised countries, including the UK, involving people who have not travelled abroad. The source of infection in UK-acquired cases is harder to pinpoint although studies by the Health Protection Agency (HPA) and the Veterinary Laboratories Agency (VLA) found that patients with non-travel associated hepatitis E were infected by the same hepatitis E virus that is carried by British pigs. 

 

The virus is excreted in the faeces of infected people and hepatitis E can be passed on to other people when food or water is contaminated with infected faeces (faecal-oral transmission).  It is also thought that hepatitis E may be passed to humans from some animals which can also become infected with HEV and shed the virus in their faeces. This is called zoonotic transmission.

 

Hepatitis E infection usually produces only mild disease and most people recover completely within one to four weeks. In rare cases, the illness can be more severe and occasionally, can be fatal. However, for pregnant women, hepatitis E is more serious and the disease is fatal in 10%–30% of pregnant women, particularly those in their third trimester.

 

There is no specific treatment for hepatitis E although patients should be seen and assessed by a doctor. Pregnant women and older people, those with weakened immune systems, and people with chronic liver disease might need closer observation for possible deterioration in liver function as they may experience more severe infection.

 

General information about hepatitis E infection is available on the Public Health Wales main website at: link 

 

More information about hepatitis E is available from the following websites:

 

Hepatitis E is most common in developing countries with inadequate environmental sanitation. Hepatitis E epidemics have been reported in Asia, the Middle East, Africa, and Central America. Some epidemics of hepatitis E have involved tens of thousands of people affected over a short period of time. People living in refugee camps or overcrowded temporary housing after natural disasters can be at particular risk.

 

Increasingly, sporadic hepatitis E cases not associated with travel have been identified in developed countries. The Health Protection Agency report that the number of confirmed cases of HEV infection increased significantly between 2003-2005. This was followed by a slight decrease in 2006 and a significant decrease in 2007. However, since 2008 numbers of cases began to increase again, showing a marked increase in 2010 (see Health Protection Agency website at: http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/HepatitisE/Surveillance/). There continues to be a high proportion (more than 20% each year) of cases in older individuals, particularly males, which may be indigenously acquired.

 

In Wales, confirmed cases increased from 2004 to 2005, markedly increased in 2006 (although data during this year are likely subject to ascertainment bias as active case finding was undertaken), decreased from 2007-2009 before increasing again during 2010 (see Data for Wales section below).

 

In response to the increase in confirmed cases during 2010, Public Health Wales is collaborating with the Health Protection Agency in undertaking a temporary enhanced surveillance of hepatitis E. Investigators can download the hepatitis E surveillance forms from:

A study into the epidemiological risks for HEV transmission in Wales for cases between January 2004- March 2009 was undertaken in 2009 by staff at the Public Health Wales Communicable Disease Surveillance Centre. Of the 158 confirmed cases of HEV infection reported in Wales during this time period, 68% were in patients aged 50 years and over and 65% of all cases were in males. A sample of these cases, who all had no history of travel to an HEV endemic area in the nine weeks preceding illness,  were further interviewed to explore clinical and exposure histories, daily routines, life-style, hobbies, shopping habits and food preferences.

 

Despite some documented limitations, the results of the study suggested that direct contact with animals or animal manure could be an important risk factor in indigenously acquired HEV infection; these include horses, cats, dogs, rabbits, rats and pigs. Being a gardener with exposure to animal manure, living in close proximity to a river, lake, pond, water stream, farm, park, or woodland could be risk factors; all of which provide increased opportunity for rodent exposure. A poster presentation of the results of this study is available from: Epidemiological risks for HEV transmission in Wales: SL Cottrell, A Mahmood, RL Salmon and R Smith [Powerpoint, 583Kb]

Laboratory-confirmed hepatitis E in Wales: 1993-2011 Year Number of laboratory-confirmed cases Rate of confirmed cases per 100,000 population 1993 0 0 1994 0 0 1995 0 0 1996 0 0 1997 1 0.03 1998 0 0 1999 0 0 2000 0 0 2001 3 0.10 2002 0 0 2003 5 0.17 2004 4 0.14 2005 30 1.02 2006* 85 2.87 2007 20 0.67 2008 17 0.57 2009 13 0.43 2010 21 0.70 2011** 14 0.46 Source: CoSurv laboratory data (CDSC Wales) * data during this year are likely subject to ascertainment bias as active case finding was undertaken ** Data as at 03/10/11.

 

In Wales, hepatitis E infection is confirmed by laboratory testing of blood serum.

 

Laboratory confirmed data for hepatitis E in Wales is compiled by our database CoSurv and it is this data that is used to generate the recent trend data for this year and for the preceding year.

 

This is raw data and has therefore not yet been subject to data cleaning and maybe incomplete. Differences in small numbers should not necessarily be interpreted as reflecting real changes. This data is made available with these caveats to enable universal access to timely data on broad trends in infectious diseases in Wales.

 

It should be noted that in 2006 active case finding of hepatitis E infections was undertaken in South Wales and will account for the marked peak in cases ascertained during that year.

 

Notification Data: Acute infectious hepatitis is one of a number of notifiable diseases. Doctors in Wales have a statutory duty to notify a 'Proper Officer' of the Local Authority of suspected cases of hepatitis  based on clinical symptoms, usually before diagnosis and type of hepatitis has been confirmed by laboratory testing. Laboratories have a similar duty to report the identification of hepatitis E virus.

 

Before 2011, these data were compiled into the statutory weekly Statutory Notifications of Infectious Diseases (NOIDs) report by the Health Protection Agency (HPA) Centre for Infections in Colindale, North London. The NOIDS reports are available to download from the HPA website. Since July 2010 the proper officers in Wales are obliged to disclose notifications made to them to Public Health Wales NHS Trust instead of NOIDS although in practice, many notifications in Wales are still also passed to NOIDS for completeness.

 

If further surveillance data for hepatitis E in Wales is required, it may be possible to provide it on special request. Please use the surveillance data request form provided from this link.