Recombinant adenovirus as a model to evaluate the efficiency of free chlorine disinfection in filtered water samples

Molecular Detection of Human Enteric Adenoviruses in Water Samples Collected from Lake Victoria Waters Along Homa Bay Town, Homa Bay County, Kenya

Lake Victoria is the primary source of water for millions of people in the Sub-Saharan Africa region. In recent years, population development around the lake has resulted in compromised sanitation standards resulting in increased faecal pollution of the lake. Consequently, this condition has increased the chances of waterborne enteric viruses, such as adenoviruses' circulation in the community. Adenoviruses can affect health in both humans and animals by causing a myriad of diseases including the gastrointestinal infections. The study aimed to detect contamination of the lake water with pathogenic human adenoviruses along Homa Bay town, Homa Bay County, Kenya. To examine the presence of adenoviral genome, we collected a total of 216 (monthly n = 36) water samples from six different locations marked by high levels of anthropogenic activities along the shoreline. Molecular amplification technique using the nested PCR procedure was used to detect the genomes from the water samples. Human adenoviruses were detected in 11 samples (5.09%). Statistical analyses indicated a significant correlation between adenovirus presence and the approximate distance from pit latrines and sewage treatment works at the area. The findings indicate that faecal contamination of the lake waters originated from the point sources. The findings also suggest a possibility of elevated levels of faecal pollution in different surface waters within the lake basin. The findings indicate that some of the enteric viruses circulating in the local community are human adenovirus type 40, and 41. The data may provide a basis for recognizing the need to prioritize environmental monitoring for enteric virus contamination on an on-going basis.

Predictive Water Virology: Hierarchical Bayesian Modeling for Estimating Virus Inactivation Curve

Hazard analysis and critical control point (HACCP) are a series of actions to be taken to ensure product consumption safety. In food poisoning risk management, researchers in the field of predictive microbiology calculate the values that provide minimum stress (e.g., temperature and contact time in heating) for sufficient microbe inactivation based on mathematical models. HACCP has also been employed for health risk management in sanitation safety planning (SSP), but the application of predictive microbiology to water-related pathogens is difficult because the variety of pathogen types and the complex composition of the wastewater matrix does not allow us to make a simple mathematical model to predict inactivation efficiency. In this study, we performed a systematic review and meta-analysis to construct predictive inactivation curves using free chlorine for enteric viruses based on a hierarchical Bayesian model using parameters such as water quality. Our model considered uncertainty among virus disinfection tests and difference in genotype-dependent sensitivity of a virus to disinfectant. The proposed model makes it possible to identify critical disinfection stress capable of reducing virus concentration that is below the tolerable concentration to ensure human health.

Main Microbiological Pollutants of Bottled Waters and Beverages

Although consumption of quality drinking water should be available to anyone, without any risk, in reality, for the people living in poor countries, safe water sources are often not an option. In order to eliminate the risk of disease, people prefer to use bottled water, or even bottle beverages, considering them uncontaminated, sterile products. However, the evidence showed that some microbial species belonging to autochthonous water microbiota or even pathogenic species may contaminate and could, in certain conditions, multiply beyond measure in the bottled products. Sometimes, although the bottled water or beverages meet the quality requirements, still, they could be responsible by some water- or food-borne diseases. This chapter presents the main microbial contaminants of these products and the associated risk for waterborne/food-borne diseases.

Adenovirus Replication Cycle Disruption from Exposure to Polychromatic Ultraviolet Irradiation

Polychromatic ultraviolet (UV) light with bandwidth of 20 nm and peak emission centered at 224, 254, or 280 nm (UV₂₂₄, UV₂₅₄, and UV₂₈₀, respectively) were used to inactivate human adenovirus type 2 (HAdV-2). Quantitative polymerase chain reaction (qPCR) and reverse transcriptase qPCR assays were used to elucidate the step in the HAdV-2 replication cycle that was disrupted after UV exposure. UV treatment at any of the wavelengths analyzed did not inhibit association of HAdV-2 to the host cells even after exposure to a fluence (UV dose) that would produce a virus inactivation efficiency, measured by plaque assay, greater than 99.99%. In contrast, UV irradiation at all three peak emissions disrupted early E1A gene transcription and viral DNA replication, but different mechanisms appeared to be dominating such disruptions. UV₂₂₄ seemed to have little effect on the integrity of the viral genome but produced a structural transformation of the viral capsid that may inhibit the delivery of viral genome into the host cell nucleus. On the other hand, UV₂₅₄ and UV₂₈₀ did not affect the integrity of the viral capsid, but the mutations they produced on the viral genome might cause the inhibition of the early gene transcription and DNA replication after the viral genome successfully translocated into the host cell nucleus.

Human and animal enteric virus in groundwater from deep wells, and recreational and network water

This study was designed to assess the presence of human adenovirus (HAdV), rotavirus-A (RVA), hepatitis A virus (HAV), and porcine circovirus-2 (PCV2) in groundwater from deep wells, and recreational and network waters. The water samples were collected and concentrated and the virus genomes were assessed and quantified by quantitative PCR (qPCR). Infectious HAdV was evaluated in groundwater and network water samples by integrated cell culture using transcribed messenger RNA (mRNA) (ICC-RT-qPCR). In recreational water samples, HAdV was detected in 100 % (6/6), HAV in 66.6 % (4/6), and RVA in 66.6 % (4/6). In network water, HAdV was detected in 100 % (6/6) of the samples (these 83 % contained infectious HAdV), although HAV and RVA were not detected and PCV2 was not evaluated. In groundwater from deep wells, during rainy period, HAdV and RVA were detected in 80 % (4/5) of the samples, and HAV and PCV2 were not detected; however, during dry period, HAdV and RVA were detected in 60 % (3/5), HAV in only one sample, and PCV2 in 60 % (4/5). In groundwater, all samples contained infectious HAdV. PCV2 presence in groundwater is indicative of contamination caused by swine manure in Concórdia, Santa Catarina, Brazil. The disinfection of human and animal wastes is urgent, since they can contaminate surface and groundwater, being a potential threat for public and animal health.