Ryan G. Sinclair

Viruses in recreational water-borne disease outbreaks: a review.

Viruses are believed to be a significant cause of recreationally associated water‐borne disease. However, they have been difficult to document because of the wide variety of illnesses that they cause and the limitations in previous detection methods. Noroviruses are believed to be the single largest cause of outbreaks, which have been documented in the published literature 45% (n = 25), followed by adenovirus (24%), echovirus (18%), hepatitis A virus (7%) and coxsackieviruses (5%). Just under half of the outbreaks occurred in swimming pools (49%), while the second largest outbreak occurred in lakes or ponds (40%). The number of reported outbreaks associated with noroviruses has increased significantly in recent years probably because of better methods for virus detection. Inadequate disinfection was related to 69% (n = 18) of swimming pool outbreaks. A lack of required reporting and nonuniform water quality and chlorination/disinfection standards continues to contribute to water‐borne recreational disease outbreaks.

Persistence of Category A Select Agents in the Environment

The intentional use of biological agents as weapons could result in deaths in numbers comparable to those expected from the use of nuclear weapons. It is one of the most significant terrorism threats ([16][1], [82][2]) and has the potential to catalyze a general breakdown of society through a loss

Criteria for Selection of Surrogates Used To Study the Fate and Control of Pathogens in the Environment

ABSTRACT This article defines the term surrogate as an organism, particle, or substance used to study the fate of a pathogen in a specific environment. Pathogenic organisms, nonpathogenic organisms, and innocuous particles have been used as surrogates for a variety of purposes, including studies on survival and transport as well as for method development and as “indicators” of certain conditions. This article develops a qualitative surrogate attribute prioritization process and allows investigators to select a surrogate by systematically detailing the experimental process and prioritizing attributes. The results are described through the use of case studies of various laboratories that have used this process. This article also discusses the history of surrogate and microbial indicator use and outlines the method by which surrogates can be used when conducting a quantitative microbial risk assessment. The ultimate goal of selecting a sufficiently representative surrogate is to improve public health through a health-based risk assessment framework. Under- or overestimating the resistance, inactivation, or movement may negatively impact risk assessments that, in turn, will impact health assessments and estimated safety levels. Reducing uncertainty in a risk assessment is one of the objectives of using surrogates and the ultimate motive for any experiment investigating potential exposure of a pathogen.

Microbial contamination in kitchens and bathrooms of rural Cambodian village households

Aims:  To quantify microbial contamination on kitchen and bathroom surfaces (fomites) in rural Cambodian homes and to compare these concentrations to similar data from the United States and Japan.

Evaluation of Select Sensors for Real-Time Monitoring of Escherichia coli in Water Distribution Systems

ABSTRACT This study evaluated real-time sensing of Escherichia coli as a microbial contaminant in water distribution systems. Most sensors responded to increased E. coli concentrations, showing that select sensors can detect microbial water quality changes and be utilized as part of a contaminant warning system.

Mixed Methods Pilot Study of Sharing Behaviors among Waterpipe Smokers of Rural Lao PDR: Implications for Infectious Disease Transmission

To date, the sharing behaviors associated with the homemade tobacco waterpipe used in rural areas of the Western Pacific Region have not been studied. Evidence from studies of manufactured waterpipes raises the possibility of infectious disease transmission due to waterpipe sharing. The objective of our pilot study in rural Lao People’s Democratic Republic (PDR) was to identify and measure the prevalence of waterpipe sharing behaviors. We first conducted ethnographic studies to investigate waterpipe-smoking behaviors. These findings were then used to develop an interviewer-administered household survey that was used in a sampling of waterpipe smokers from three villages of the Luang Namtha province of Lao PDR (n = 43). Sampled waterpipe smokers were predominantly male (90.7%), older (mean age 49, SD 13.79), married (95.4%), farmers (78.6%), and had completed no primary education. Pipes were primarily made from bamboo (92.9%). Almost all (97.6%) smokers were willing to share their pipe with others. At the last time they smoked, smokers shared a pipe with at least one other person (1.2 ± 0.5 persons). During the past week, they had shared a pipe with five other persons (5.2 ± 3.8 persons). The high prevalence of sharing behaviors among waterpipe smokers in rural Southeast Asia raises the possibility that this behavior provides important and unmeasured social network pathways for the transmission of infectious agents.

Real-Time Detection of Escherichia coli in Water Pipe Using a Microfluidic Device with One-Step Latex Immunoagglutination Assay

The number of cases involving produce-associated illnesses has been increasing recently, especially those related to pathogen-contaminated irrigation water. Clearly, real-time and extremely sensitive detection of these pathogens is needed to ensure that produce-related farming procedures are safe. In our study, we demonstrated that the use of a microfluidic system can detect Escherichia coli in a water pipe at laminar and turbulent flow regimes. A one-step latex immunoagglutination assay was performed within a microfluidic device that uses fiber optics to detect pathogens. The results were then successfully validated by using cultured E. coli and a salt tracer. The detection of the E. coli was thus accomplished in real time (<5 min per each assay) and at concentrations less than 10 cfu mL-1, suggesting that the system is appropriate for monitoring waterborne pathogens. Specifically, our study found that, in a straight pipe, cell fragments and free antigens of E. coli behave in ways similar to the salt tracer, while viable E. coli cells do not. The computational fluid dynamics model successfully predicted flow dispersion and presents the possibility of modeling the behavior of waterborne pathogens. This study also suggests the possibility of early detection of systemic contamination and timely public health risk assessment before a costly disease outbreak occurs.

Assessment of MS-2 phage and salt tracers to characterize axial dispersion in water distribution systems.

The present study investigates the axial dispersion and retardation patterns of viruses in a pressurized water distribution pipe using MS-2 as a surrogate. The results were obtained by using computational fluid dynamics (CFD), along with a hydraulic and water quality model. These models included the plug flow assumption and were first used to estimate transport mechanisms along a pipe. These prediction–model results were compared to experimental data using sodium chloride as a chemical tracer. Significant axial dispersion and retardation (or tailing) was found to exist under laminar flow conditions with high dispersion coefficients (E) estimated by CFD runs and salt tracer experiments. A similar dispersion pattern was also observed for MS-2, along with a long tailing pattern, which is particularly unique. The commonly used water quality model showed no axial dispersion (E = 0) under any flow regimes; thus, the plug flow assumption could produce significant errors in predicting the transport phenomena of chemical and biological constituents in water distribution systems. On the other hand, the dispersion curves predicted by the plug flow model and CFD are in good agreement with the experimental data in the turbulent flow regime, although using computational methods to predict microbial retardation is intrinsically difficult. Because the MS-2 demonstrated considerable temporal retardation and because its detection limit is much lower than that of the salt tracer, MS-2 should make an excellent tracer for characterizing viral transport in water distribution systems.

Carbon monoxide levels in water pipe smokers in rural Laos PDR

Regional trends indicate that tobacco waterpipe (TWP) smoking is common in the Eastern Mediterranean Region (EMR) and is increasing in global popularity.1–4 EMR TWP smokers use a commercially manufactured pipe (figure 1A)5 that is loaded with tobacco and sold in pre-weighed packages of 50 g or more. The EMR TWP user inhales a combination of tobacco and charcoal smoke after it has passed through water. Despite the mistaken belief that the water bath of the EMR TWP filters out harmful and/or addictive components,3 ,6–8 recent data indicates that EMR TWP smokers are exposed to biologically harmful levels of nicotine, tar, metals, volatile aldehydes, polycyclic aromatic hydrocarbons, volatile organic compounds and expired carbon monoxide (CO).9 Figure 1 (A) Eastern mediterranean tobacco waterpipe (left), (B) Asian tobacco waterpipe (right). In the Western Pacific Region, the Asian tobacco water pipe (ATWP, figure 1B) is a homemade pipe that consists of a tube (made of …

Biochemical validation of self reported quit rates among Buddhist monks in Cambodia

Smoking cessation programmes in Cambodia have found that Buddhist monks are highly motivated to quit smoking. Although over 23.4% of all Buddhist monks smoke,1 the self reported quit rates average 87%. The Adventist Development Relief Agency’s (ADRA) “Khmer Quit Now” programme has achieved this success through a five day smoking cessation class. ADRA has found that Buddhist monk peer support groups work well; the one year quit rate has been a consistent 87% over four years in five different Cambodian provinces. This extraordinary quit …