Charles Gerba

The University of Arizona | UA · Department of Soil, Water, and Environmental Science

Restroom use has been implicated in a number of viral outbreaks. In this study, we apply quantitative microbial risk assessment to quantify the risk of viral transmission by contaminated restroom fomites. We estimate risk from high-touch fomite surfaces (entrance/exit door, toilet seat) for three viruses of interest (SARS-CoV-2, adenovirus, norovir...

The study objective was to evaluate human faecal contamination impacts in the Yal-ku lagoon in the Mexican Caribbean and to estimate adenovirus infection and illness risks associated with recreational exposure during water activities. A total of 20 water samples (10 from each site × 2 sites) (50 L) were collected monthly over a period of 12 months...

Background It is believed that as much as 80% of common infections are spread by the hands. Touching surfaces (fomites) contaminated with infectious microorganisms results in their transfer to the hands (fingers). Subsequent touching of the mouth, nose, or skin can result in their transmission. Disinfection of surfaces has been found to reduce such...

There have been a considerable number of antifungal studies that evaluated natural products (NPs), such as medicinal plants and their secondary metabolites, (phenolic compounds, alkaloids), essential oils, and propolis extracts. These studies have investigated natural antifungal substances for use as food preservatives, medicinal agents, or in agri...

On-site – mainly septic systems – and centralized wastewater treatment systems treat vast volumes daily. Most wastewater from septic systems reaches soils via covered leaching beds. Municipal biosolids are applied to cropland for their nutrient value after receiving treatments of various intensity but the soil is relied on to act as a treatment med...

Objective 1. To work alongside industry partners to conduct a longitudinal study on the impact of flood water(s) on the presence and persistence of microbiological indicators and pathogens on lands used to grow fresh produce. Funding for this project was provided through the CPS Campaign for Research. ROCK | University of Arizona CPS: Flood Rapid R...

Pathogen removal in managed aquifer recharge (MAR) systems is dependent upon numerous operational, physicochemical water quality, and biological parameters. Due to the site-specific conditions affecting these parameters, guidelines for specifying pathogen removal have historically taken rather precautionary and conservative approaches in order to p...

Background Hard and soft surfaces (fomites) can play a role in the transmission of both enteric and respiratory viruses. Transmission can occur by touching of contaminated surfaces and bringing the hand to the either the mouth or nose or by re-aerosolization of the virus from the surface. In adults face touching occurs every 3 to 4 minutes. The amo...

Exposure models are useful tools for relating environmental monitoring data to expected health outcomes. The objective of this study was to 1) compare two Legionella shower exposure models, and 2) develop a risk calculator tool for relating environmental monitoring data to estimated Legionella infection risks and Legionnaires’ Disease (LD) illness...

Twenty-five untreated barn owl pellets were analyzed for enteric pathogens and fecal indicator bacteria. Although no enteric protozoan parasites or viruses were detected, sixty percent were positive for total coliforms and fifty-two percent were positive for E. coli. C. jejuni was only presumptively found in sixty-four percent of the pellets but th...

Background The recent pandemic of CoVid19 has increased our need to assess the impact of disinfectants on the inactivation of human coronaviruses. The goals of this study were 1) quantify the disinfection of SARS-CoV-2 and human coronavirus 229 inactivations by various quaternary ammonium formulations, and 2) demonstrate the impact of disinfectants...

The use of contaminated water to irrigate crops by surface, sprinkler, or conventional drip irrigation represents a significant public health concern due to the presence of multiple microbial pathogens associated with gastrointestinal disease. In this study, Escherichia coli and MS2 bacteriophage were used as microbial surrogates to evaluate the co...

Because of the difficulty and cost of detecting waterborne enteric pathogens, indicator organisms have been used since the beginning of the twentieth century. Much of the work in this area has focused on bacterial indicators, such as coliform and fecal coliform bacteria. However, it has been recognized in the last 30 years that these traditional in...

The birth of bacterial genomics since the mid-1990s brought withit several conceptual modifications and wholly new controversies. Working beyond the scope of the neo-Darwinian evolutionary synthesis, a group of leading microbial evolutionists addresses the following and related issues, often with markedly varied viewpoints: · Did the eukaryotic nuc...