Hepatitis E: Overview and Management in Namibia

Introduction

HEV is an inflammation of the liver that can be caused by HEV virus, chemicals, drugs, alcohol, inherited diseases, or patient’s own immune system characterized by diffuse inflammatory changes and necrosis of the liver.

Hepatitis E virus (HEV) forms part of Orthohepevirus genus belonging to a family Hepeviridae, under four species being A to D with an infection believed to be caused by strains of species A (Smith et al., 2020). In addition, species A is further divided into 8 genotypes, two (HEV1 and HEV2) of which are endemic in various animal species (Ouoba, 2019), however, HEV3 and HEV4 can still spread causing zoonotic human infections. On the other hand, other genotypes appear to affect mainly wild boar (HEV5, HEV6) and camels (HEV7, HEV8) despite a HEV7 human infection being reported (Purdy et al, 2017; van Tong et al, 2016). In addition, HEV 1 and 2 have so far only been found have been contracted by human from fecal contaminated drinking water.

HEV is a waterborne emergent infection and thus a source-originated epidemic of acute disease with a case fatality rate deemed to vary by age and pregnancy status (Rein, Stevens, Theaker, Wittenborn, & Wiersma, 2012). In addition, the virus usually spread by the fecal-oral route with fecal contaminated drinking water known to be the main source of the virus. However, each of about four HEV genotypes that cause illness in humans presents with unique epidemiological and clinical features in developing as compared to developed countries. In an area where HEV is endemic, case(s) typically present either as a large outbreak and sporadic cases (WHO, 2017). Even so, various new HEV-like viruses have been detected in numerous animal species, inclusive of carnivores; however, the phylogenetic conjunctions amongst these viruses remain poorly resolved, as parts of them were known to be rodent-related (Lanszki, et al., 2020). In addition, the red fox which is a universal well known carnivore is known to be a host of numerous viruses that transmit from wildlife to humans or domestic animals which has a potential to transmit and circulate rodent-borne HEV.

Background

A male patient in Hong Kong became the first person in the world to be confirmed with a strain of HEV virus which was previously found only in rats and other animals (Medical express, 2018). Despite the unknown mode of contraction, the man is believed to have accidentally ingested droppings which were contaminated with HEV. In India however, the first HEV patient was discovered in Kashmir Valley during the 1978 epidemic, which further infected approximately 52,000 persons, causing a total of 1700 fatalities (Purdy& Khudyakov, 2011). Since then, the world recorded a wide spread of HEV causing approximately 20-million infections worldwide each year, of which 17.7-millions were asymptomatic resulting into 44,000 deaths in 2015. Despite being rare in developed countries, locally acquired HEV infection can result in acute Hepatitis with tendency to progress to chronic HEV mainly among solid organ transplant recipients (WHO, 2017; WHOa, 2020).

To date, HEV became the most common cause of acute viral hepatitis among adults throughout the Africa continent (Kaba, 2009). The is however an increase in the number of HEV cases in 28 of 56 African countries as a result of poor sanitation as well as lack of safe drinking water. The virus cases are mainly attributed to pregnant mothers, fetuses as well as to those who are immune compromised. Since 1979, a total of 17 HEV outbreaks have been so far recorded in Africa.