|
| Genotype | 1 | 2 | 3 | 4 |
|
| Host | Human; also isolated from pig | Human exclusively | Human, pigs, and other mammalian species |
|
Route of
transmission |
Fecal-oral; vertical transmission; zoonotic (genotype 1) |
Zoonotic (usually swine, with humans being accidental hosts); environmental
(shellfish, river); blood transfusion |
|
Geographical
distribution | Mainly Asia and Latin America (Cuba,
Venezuela, and Uruguay) | Mexico and West Africa | Worldwide | China, East Asia, Central Europe, and America |
|
Epidemiological
features | Causes epidemic
outbreaks and sporadic cases in
developing countries; occasionally in travelers returning from developing countries | Causes epidemic
outbreaks and sporadic cases
in developing countries | Causes sporadic autochthonous cases in developed countries |
|
| Seasonality | Yes (outbreaks in flooding/monsoon) | No |
|
Clinical
presentation | Mostly asymptomatic;
acute self-limited hepatitis | Mostly asymptomatic; acute self-limited hepatitis |
Varies from asymptomatic to acute self-limited hepatitis and may lead to chronicity in immunosuppressed cases (HEV3) |
|
| Age | Adolescents and young (15–30 y) | Middle-aged and elderly (>50 y) |
|
| Gender (M : F) | 2 : 1 | >3 : 1 |
|
| Prognosis | High mortality in pregnancy and in patients with underlying chronic liver disease | Fulminant hepatitis has not been noted in HEV2 |
Higher overall mortality rate relative to
genotype 1; higher mortality among older adults |
|
| Chronic infection | No | Yes | Yes |
|
