Hepatitis E: Discovery, global impact, control and cure

Table 1 Hepatitis E: Global epidemiology and clinical profile

	Developing countries		Developed countries
Genotypes	HEV-1	HEV-2	HEV-3	HEV-4
Distribution	Asia, Africa, Latin America	Mexico, West Africa	Worldwide	China, East Asia, Central Europe
Disease pattern	Epidemic, Endemic		Autochthonous, sporadic, case-clusters
Attack rate	About 1 in 2		67%-98% asymptomatic
Seasonality	Yes		No
Reservoir	Human		Animals (pig, boar, deer)
Transmission	Water, person-to-person, vertical		Zoonotic-food-borne, vocational, infected water
Transfusion-associated	Reported		Yes (well-studied)
Seroprevalence	Low (< 15 yr), rapid increase		Steady increase throughout age groups; varies 7% to 21%
	(15-30 yr), plateau at 30%-40%
Seroincidence	64/1000-yr		30 (South France), 2 (United Kingdom)
			7 (United States)/1000-yr
Age (yr)	15-40		> 50
Sex	2:1		> 3:1
Clinical outcome	Self-limiting in most		Self-limiting in most
Risk factors	Pregnancy, Cirrhosis		Cirrhosis, LTx, HIV
Deaths in pregnancy	High (25%)		Not reported
HEV superinfections	Common, poor outcome		Reported, poor outcome
Extra-hepatic disease	Yes		Yes
Chronic infection	Not reported		HEV-3; SOT, HIV, hem NP
Burden	3.4 million cases/yr, 70000 deaths, 3000 still births		Unknown

Adopted from Khuroo et al[143] 2016. HEV: Hepatitis E virus; HIV: Human immunodeficiency virus.