Hepatitis E Virus in Water Environments: A Systematic Review and Meta-analysis

Abstract

Hepatitis E virus (HEV) is responsible for acute hepatitis in humans, through foodborne, zoonotic, and waterborne transmission routes. This study aimed to assess the prevalence of HEV in water matrices. Six categories were defined: untreated and treated wastewater, surface water (river, lake, and seawater), drinking water, groundwater, and other water environments (irrigation water, grey water, reservoir water, flood water, and effluent of pig slaughterhouse). We searched PubMed, Web of Science, Global Index Medicus, and Excerpta Medica Database. Study selection and data extraction were performed by at least two independent investigators. Heterogeneity (I2) was assessed using the χ2 test on the Cochran Q statistic and H parameter. Sources of heterogeneity were explored by subgroup analysis. This study is registered with PROSPERO, number CRD42021289116. We included 87 prevalence studies from 58 papers, 66.4% of which performed in Europe. The overall prevalence of HEV in water was 9.8% (95% CI 6.4–13.7). The prevalence was higher in untreated wastewater (15.1%) and lower in treated wastewater (3.8%) and in drinking water (4.7%). In surface water, prevalence was 7.4%, and in groundwater, the percentage of positive samples, from only one study available, was 8.3%. Overall, only 36.8% of the studies reported the genotype of HEV, with genotype 3 (HEV-3) prevalent (168 samples), followed by HEV-1 (148 sample), and HEV-4 (2 samples). High-income countries were the most represented with 59/87 studies (67.8%), while only 3/87 (3.5%) of the studies were performed in low-income countries. The overall prevalence obtained of this study was generally higher in industrialized countries. Risk of bias was low in 14.9% of the studies and moderate in 85.1%. The results of this review showed the occurrence of HEV in different waters environments also in industrialized countries with sanitation and safe water supplies. While HEV transmission to humans through water has been widely demonstrated in developing countries, it is an issue still pending in industrialized countries. Better knowledge on the source of pollution, occurrence, survival in water, and removal by water treatment is needed to unravel this transmission path. Graphical Abstract

Hepatitis E in Kathmandu Valley: Insights from a Representative Longitudinal Serosurvey

“…This finding aligns with previous studies that have identified contaminated water as a primary transmission route for HEV (21,22). The fact that a majority of the incident seroconversions were observed in individuals who consumed untreated or occasionally treated surface water further underscores the importance of water quality in HEV exposure The spread of HEV to the environment might pollute surface waters, which could act as the source of infection for both humans and animals (23). Moreover, the occurrence of HEV in different water environments, even in industrialized countries with sanitation and safe water supplies, has been documented, emphasizing the need for continuous monitoring and intervention (23).…”

A pilot on integrated wildlife monitoring at European scale: environmental detection of selected pathogens in the European Observatory of Wildlife

“…Hepatitis E virus (HEV): although we did not obtain positive results, HEV has been previously assessed in water matrices, including untreated and treated wastewater, surface water (river, lake, and seawater), drinking water, groundwater, and other water environments (irrigation water, grey water, reservoir water, flood water, and effluent of pig slaughterhouse) (Takuissu et al 2022). However, to our known, no research has focused on water sources predominantly used by wildlife.…”

Mediterranean springs: Keystone ecosystems and biodiversity refugia threatened by global change

“…Human activities, such as intensive livestock farming and wastewater discharges, have also contributed to the degradation of the microbiological quality of groundwater, aquifers, and springs (Savio et al., 2018; Stevens et al., 2022; Takuissu et al., 2022). Fecal contamination infiltrates soils and reaches groundwater and aquifers, even at great depths.…”

“…Recent studies have indicated a general underestimation of aquifer contamination through enlarged cracks and fissures (Hartmann et al., 2021). Pathogenic bacteria, such as Escherichia coli and other coliforms, and enteric viruses like Norovirus , Rotavirus , hepatitis A and E viruses, as well as protozoa like Cryptosporidium and Giardia , are increasing, compromising springs as secure freshwater resources (An & Breindenbach, 2005; Aqso et al., 2014; Blanco et al., 2017; Davidson et al., 2016; Murphy et al., 2017; Ryu et al., 2019; Takuissu et al., 2022).…”