Hepatitis E virus: overseas epidemics and Victorian travellers

To the Editor: Hepatitis E virus (HEV) infection is uncommon in Australia. The HEV cases detected are almost always in patients who have recently arrived from HEV-endemic regions of the world.1 We previously reported a significant increase in highly reactive serology results for anti-HEV IgG antibodies measured by enzyme im-munoassay (EIA) at the Victorian Infectious Diseases Reference Laboratory (VIDRL) in the first 6 months of 2004.2

Nine of the 10 Victorian patients with highly reactive samples in the previous report had had a history of recent clinically compatible illness and travel in a disease-endemic region within the incubation period (2–9 weeks). This indicated a strong association between highly reactive anti-HEV IgG measured by EIA and acute HEV infection, as has been shown previously.3 At the time, we hypothesised an association with overseas HEV epidemics, particularly in India, as seven of the nine patients with acute HEV infection had travelled there.

We have now reviewed HEV serology results at VIDRL for the subsequent 9 months and compared them with our ex-perience of the past 5 years (Box). In the first quarter of 2005, we recorded the highest quarterly number of highly reactive anti-HEV serology results since testing commenced at VIDRL. Also marked on the figure are the dates, over the same time period, when an outbreak of hepatitis in India (either suspected or confirmed to be caused by HEV) was reported on ProMED-mail, the global electronic reporting program for emerging diseases hosted by the International Society for Infectious Diseases (http://www.promedmail.org).

It would appear that epidemic HEV activity in India is reflected in significant increases in the number of highly reactive anti-HEV serology results in our laboratory. In fact, as shown in the Box, increases in highly reactive anti-HEV serology at VIDRL have sometimes preceded an outbreak noti-fication on ProMED-mail, and may provide early warning of such an event. A similar association is not observed for epidemics in other countries.

Travellers to developing countries must be advised of preventive measures against HEV and other enterically transmitted diseases, and a diagnosis of HEV infection should be considered in any febrile traveller recently arrived from an HEV-endemic area, particularly if jaundice or abnormal liver function tests are present. This is especially important in pregnant women because of the risk of fulminant hepatitis, with maternal mortality in excess of 20% in the third trimester.4 All cases should be notified to state health authorities.

Highly reactive anti-HEV IgG EIA results at VIDRL per quarter, 1 Apr 2000 to 31 Mar 2005. Also marked are confirmed (in bold) or suspected epidemics of HEV in India listed on ProMED-mail* during the same period

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EIA = enzyme immunoassay. HEV = hepatitis E virus. VIDRL = Victorian Infectious Diseases Reference Laboratory.
* Available at <http://www.promedmail.org>.