Outbreaks of hepatitis E possible in US, Japan, and Europe

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BMJ 2004;329:1308 (4 December), doi:10.1136/bmj.329.7478.1308-f

Outbreaks of hepatitis E possible in US, Japan, and Europe

Quebec Spurgeon

The hepatitis E virus (HEV), which was identified as recently as 1980 and

has caused massive epidemics of acute hepatitis in Asia and outbreaks in

Africa and Iraq, has turned up in industrialised countries in strains that

seem to have the potential to cause explosive epidemics, says an article in

the New England Journal of Medicine (2004;351:2367-8).

Authors Suzanne Emerson and Purcell, from the US National Institutes

of Health, suggest that " it is simply our good fortune that (epidemics like

those in Sudan and Iraq, where the infrastructure has broken down) have so

far been held in check by better sanitation. "

No treatment exists for hepatitis E, and no vaccine exists to prevent it,

say the authors. Hepatitis E is best described as an opportunistic pathogen,

and both the virus and the disease appear to be virtually everywhere. The

incidence varies widely according to region.

" Although exceedingly rare, locally acquired hepatitis E has now been found

in many industrialised countries, including the United States, Japan, and

countries of the European Union. However, the prevalence of antibodies to

HEV is much higher than expected in these countries (as high as 20% among

blood donors in some regions of the United States), given the rarity of the

disease.

" A virus closely related to human HEV has been isolated from swine in many

developing and industrialised countries, including the United States.

Therefore, the spectre of hepatitis E as a zoonotic disease that can be

acquired from animals has arisen. Indeed, recent clusters of cases of

hepatitis E in Japan have been traced to the ingestion of undercooked deer

meat and pig liver . . . it is an area that requires exploration, " the

authors suggest.

The hepatitis E virus was originally identified as the culprit in the

waterborne Asian epidemics, and contamination of water was again implicated

in Sudan and Iraq, where crowded unsanitary conditions, inadequate sewage

treatment, and erratic water supplies have encouraged the virus to thrive.

Between May and August of 2004, almost 4000 suspected cases of hepatitis E

were reported by health clinics in the greater Darfur region of Sudan (BMJ

2004;329:420, 21 Aug).

Reported cases in Sadr City and Mahmudiya in Iraq number in the hundreds

rather than the thousands, but the lower numbers could well reflect

under-reporting and the lack of a routine diagnostic test for the virus.

Diagnosis requires laboratory amplification of viral genomes found in serum

and faeces during the acute phase of the disease or detection of antibodies

during the convalescent stage, and diagnostic serologic tests are not

available or licensed in many countries.

Symptoms common to all viral hepatitis are jaundice, anorexia, hepatomegaly,

abdominal pain, nausea, vomiting, and fever. Full recovery is usual in most

groups; mortality ranges from 0.5-4% in the general population, but up to

20% among pregnant women.