Hepatitis E virus-based evaluation of a virion concentration method and detection of enteric viruses in environmental samples by multiplex nested RT-PCR

Abstract

Aims: The prevalence of enteric viruses in drinking and river water samples collected from Pune, India was assessed. During an outbreak of HEV in a small town near pune, water samples were screened for enteric viruses. Methods and Results: The water samples were subjected to adsorption–elution‐based virus concentration protocol followed by multiplex nested PCR. Among 64 Mutha river samples, 49 (76·56%) were positive for Hepatitis A Virus, 36 (56·25%) were positive for Rotavirus, 33 (51·56%) were positive for Enterovirus and 16 (25%) were positive for Hepatitis E Virus RNA. Only enterovirus RNA was detected in 2/662 (0·3%) drinking water samples, and the samples from the city’s water reservoir tested negative for all four viruses. HEV RNA was detected in three out of four river water samples during HEV outbreak and partial sequences from patients and water sample were identical. Conclusions: The study suggests absence of enteric viruses both in the source and in the purified water samples from Pune city, not allowing evaluation of the purification system and documents high prevalence of enteric viruses in river water, posing threat to the community. Significance and Impact of the Study: The rapid, sensitive and relatively inexpensive protocol developed for virological evaluation of water seems extremely useful and should be adapted for evaluating viral contamination of water for human consumption. This will lead to development of adequate control measures thereby reducing disease burden because of enteric viruses.

Epidemiology of Mammalian Hepatitis E Virus Infection

“…The route of HEV transmission during outbreaks is well established, and was usually associated with the consumption of faecally contaminated drinking water [2,3,4,5,6,9,10,43,59]. In contrast, it is poorly documented for sporadic hepatitis E cases reported in both developing and developed countries [14,21,44,60].…”

“…Case-control studies have shown that consumption of boiled water significantly reduced the risk of epidemic HEV infection [6,59]. Strong arguments supporting the faecal-oral transmission of HEV during hepatitis E outbreaks came from recent studies conducted in India and Uganda [3,4,73]. Environmental investigations showed the presence of HEV RNA (of genotype 1) in river water samples collected during hepatitis E outbreaks in India [3,73], and the presence of HEV RNA in common hand washing water collected during the Kitgum District (Uganda) hepatitis E outbreak [4].…”

“…In contrast, it is poorly documented for sporadic hepatitis E cases reported in both developing and developed countries [14,21,44,60]. To date, four major documented routes of HEV transmission have been reported: waterborne transmission [2,3,4,5,6,7,8,61]; foodborne transmission [29,48]; bloodborne transmission [62,63], and vertical transmission [64,65,66]. Person-to-person HEV transmission is rarely reported and is considered as an uncommon event, both in the context of outbreaks and sporadic infections [67,68].…”

“…In developing countries of Asia, Africa and Latin America, the faecal-oral route through drinking contaminated water is the principal route of HEV transmission, and is responsible for the majority of hepatitis E outbreaks occurring in these areas [2,3,4,5,6,7,8,59,61,73,74,75]. These outbreaks usually occur during the rainy season, floods or the monsoon, conditions facilitating contamination of pipes, groundwater and sources of drinking water by human excreta [6,7,8,59].…”

“…Mammalian hepatitis E virus (HEV), the etiological agent of hepatitis E in humans (previously known as non-A, non-B enterically-transmitted hepatitis virus), is a disease of worldwide distribution [1], usually transmitted by the oral-faecal route via contaminated water [2,3,4,5,6]. The first indication of the circulation of an enterically-transmitted non-A, non-B hepatitis virus came from two independent studies conducted in India in the 1980s [7,8].…”