Solar and Temperature Treatments Affect the Ability of Human Rotavirus Wa To Bind to Host Cells and Synthesize Viral RNA

Abstract

Rotavirus, the leading cause of diarrheal diseases in children under the age of five, is often resistant to conventional wastewater treatment and thus can remain infectious once released into the aquatic environment. Solar and heat treatments can inactivate rotavirus, but it is unknown how these treatments inactivate the virus on a molecular level. To answer this question, our approach was to correlate rotavirus inactivation with the inhibition of portions of the virus life cycle as a means to identify the mechanisms of solar or heat inactivation. Specifically, the integrity of the rotavirus NSP3 gene, virus-host cell interaction, and viral RNA synthesis were examined after heat (57°C) or solar treatment of rotavirus. Only the inhibition of viral RNA synthesis positively correlated with a loss of rotavirus infectivity; 57°C treatment of rotavirus resulted in a decrease of rotavirus RNA synthesis at the same rate as rotavirus infectivity. These data suggest that heat treatment neutralized rotaviruses primarily by targeting viral transcription functions. In contrast, when using solar disinfection, the decrease in RNA synthesis was responsible for approximately one-half of the decrease in infectivity, suggesting that other mechanisms, including posttranslational, contribute to inactivation. Nevertheless, both solar and heat inactivation of rotaviruses disrupted viral RNA synthesis as a mechanism for inactivation.O f all waterborne microbes that can cause pathogenic diseases, viruses remain the most challenging for study in aquatic environments (1-4). This is for several reasons. First, compared to bacterial pathogens, viruses are more resistant to disinfection by standard water disinfection treatments (2, 5, 6). Second, for those conditions that do indeed neutralize viruses, the molecular mechanism(s) responsible for inactivation is unclear (7,8). Third, it is only recently that technologies such as quantitative PCR (qPCR) and deep genome sequencing have allowed for the detection of viral genomes in water samples (1, 4, 9, 10).Enteric viruses include rotavirus, adenovirus, coxsackievirus, and norovirus (4). Rotavirus is the leading cause of diarrhea hospitalizations for children under 5 years of age and is responsible for the deaths of an estimated 453,000 children each year (11). Despite this impact on human health, little is known as to what conditions result in the best disinfection of rotavirus in wastewater and drinking water. In addition, it is unclear how a disinfectant functions on a molecular level to inactivate rotavirus.Rotavirus is a nonenveloped virus with a double-stranded, segmented RNA genome. Six structural proteins make up the capsid, including VP4 and VP7. For rotavirus to attach to its host cell, VP4 binds to the host cell receptors, and after a multistep process involving the VP4, VP7, and other cellular proteins, rotavirus enters the host cell through endocytosis. Upon penetration, rotavirus loses its outer capsid (VP7 and VP4), and the double-layered particle is transported to the cell cytopl...

Prevalence and clinical profile of rotavirus A infection among diarrhoeal children and phylogenetic analysis with vaccine strains in Chengdu, West China, 2009–2014

“…RVA was detected throughout the year and followed a seasonal distribution, similar to previous reports in which peaks were observed in the winter months [29][30][31] 5 years of age were correlated with temperature (r = À0.68, P = 0.01) [32], and our study also found a negative correlation between RVA-positive rate and temperature. As the total positive rate of acute gastroenteritis viruses had no correlation with temperature, it could not be the bacteria-induced food poisoning in summers that raised the total number of included diarrhoea outpatients which resulted in lower RVA-positive rates in winters.…”

“…However, in India and Republic of Congo, both vomiting and fever were significantly more commonly associated with RVA-positive cases [33,36], which may be because the study in India used ELISA to detect rotavirus and the study in Congo only included hospitalised children. We also found that outpatients in winter had significantly higher frequencies of fever and respiratory diseases than in summer, indicating RVA may be more virulent at low temperatures, which is partly consistent with the high temperature-caused loss of infectivity [32]. However, the relation between temperature and virulence has rarely been discussed and needs further study.…”

Ammonia as an In Situ Sanitizer: Influence of Virus Genome Type on Inactivation

“…Nuanualsuwan and Cliver (72) reported that the primary target of poliovirus, hepatitis A virus, and feline calicivirus inactivation at 72°C was the capsid, and that inactivation occurred by conformational change of the viral proteins. Similarly, Romero-Maraccini et al (73) proposed that rotavirus inactivation at 57°C was linked to a disruption of protein-mediated steps of the early life cycle. Finally, the virucidal mode of action of high temperature and pH may also involve a denaturation of the viral capsid proteins that allows for the release of the genome from the capsid.…”

Sunlight-mediated inactivation of health-relevant microorganisms in water: a review of mechanisms and modeling approaches

“…6a(iii)) of rotavirus, which could explain about half of the inactivation that was observed; the remaining inactivation was attributed to post-translational steps. 99 As discussed in Section 4, nucleic acid and protein monomers are susceptible to direct endogenous reactions. It is therefore likely that these reactions play a role in virus inactivation.…”