Potentially Infectious Novel Hepatitis A Virus Strains Detected in Selected Treated Wastewater Discharge Sources, South Africa.

Saïd Rachida,Maureen Beatrice Taylor

doi:10.3390/v12121468

Saïd Rachida, Maureen Beatrice Taylor

Open Access

https://doi.org/10.3390/v12121468

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Abstract

Hepatitis A virus (HAV) is a waterborne pathogen of public health importance. In South Africa (SA), unique HAV subgenotype IB strains have been detected in surface and wastewater samples, as well as on fresh produce at the point of retail. However, due to the use of molecular-based assays, the infectivity of the detected strains was unknown. Considering the potential shift of HAV endemicity from high to intermediate, which could increase the risk of severe symptomatic disease, this study investigated the identity of HAV strains detected before and after viability treatment of selected wastewater discharge samples. For one year, 118 samples consisting of sewage, treated wastewater discharge and downstream dam water were collected from five wastewater treatment plants (WWTP 1, 2, 3, 4 and 5). Unique HAV IB strains were detected in samples from all five WWTPs, with 11 of these strains carrying amino acid mutations at the immunodominant and neutralisation epitopes. A quasispecies dynamic of HAV has also been detected in sewage samples. The subsequent application of viability PCR revealed that potentially infectious HAV strains were discharged from WWTP 1, 2, 4 and 5 into the dam. Therefore, there is a potential risk of HAV exposure to communities using water sources downstream the WWTPs.

Highlights

Hepatitis A virus (HAV), a leading cause of acute hepatitis worldwide [1], is an important waterborne pathogen with significant public health impact [2,3]
Of the 79 hepatitis A virus (HAV)-positive samples which were subjected to viability treatment, potentially infectious HAV was quantified from the virus concentrates of 81% (30/37) of sewage and 90% (38/42) of treated wastewater discharge samples (Table 3)
Infectious HAV was discharged from wastewater treatment plants (WWTPs) 1, 2, 4 and 5 into the dam or rivers feeding into the dam, while no potentially infectious HAV was discharged from WWTP 3 (Table 3)

Summary

Introduction

Hepatitis A virus (HAV), a leading cause of acute hepatitis worldwide [1], is an important waterborne pathogen with significant public health impact [2,3]. Given that all infected individuals, be they symptomatic or not, shed the virus in faeces [7], the analysis of sewage, wastewater and surface water can provide a more accurate estimation of the HAV strains circulating in a specific community. This surveillance system could serve as an early warning system of potential outbreaks [8]. The translated polyprotein is cleaved into structural and non-structural proteins [1,9].

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