Highlights SARS-CoV-2 was quantified (10 1 -10 4 copies 100 mL −1 ) in southeast Virginia wastewater. RT-ddPCR was optimized to quantify SARS-CoV-2 from wastewater. 5.5 and 7.6% recoveries were observed for BCoV and BRSV, respectively. Trends in SARS-CoV-2 are apparent at the facility and regional scaleover a 21-week study.

The ongoing COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) requires a significant, coordinated public health response. Assessing case density and spread of infection is critical and relies largely on clinical testing data. However, clinical testing suffers from known limitations, including test availability and a bias towards enumerating only symptomatic individuals. Wastewater-based epidemiology (WBE) has gained widespread support as a potential complement to clinical testing for assessing COVID-19 infections at the community scale. The efficacy of WBE hinges on the ability to accurately characterize SARS-CoV-2 concentrations in wastewater. To date, a variety of sampling schemes have been used without consensus around the appropriateness of grab or composite sampling. Here we address a key WBE knowledge gap by examining the variability of SARS-CoV-2 concentrations in wastewater grab samples collected every 2 hours for 72 hours compared with corresponding 24-hour flow-weighted composite samples. Results show relatively low variability (mean for all assays = 741 copies 100 mL-1, standard deviation = 508 copies 100 mL-1) for grab sample concentrations, and good agreement between most grab samples and their respective composite (mean deviation from composite = 159 copies 100 mL-1). When SARS-CoV-2 concentrations are used to calculate viral load, the discrepancy between grabs (log10 difference = 12.0) or a grab and its associated composite (log10 difference = 11.8) are amplified. A similar effect is seen when estimating carrier prevalence in a catchment population with median estimates based on grabs ranging 62-1853 carriers. Findings suggest that grab samples may be sufficient to characterize SARS-CoV-2 concentrations, but additional calculations using these data may be sensitive to grab sample variability and warrant the use of flow-weighted composite sampling. These data inform future WBE work by helping determine the most appropriate sampling scheme and facilitate sharing of datasets between studies via consistent methodology.

Microbial source tracking can identify waterbodies at risk of contamination using host-associated molecular markers. No assay used for microbial source tracking is both 100% host-specific and sensitive for human or animal fecal contamination. Using literature sensitivity and specificity values, Bayes’ Theorem for conditional probability was applied to the human fecal-associated HF183 marker in a microbial source tracking context. Type I and Type II error rates were examined across a range of priors. Conditional probabilities were investigated using two human-associated markers, HF183 and HumM2, concurrently. Cumulative probability analysis was used to explore the likelihood of true contaminant detection using multiple samples. Probability of human fecal contamination was calculated for all combinations of positive and negative marker results given three samples. Results demonstrate the respective influence that specificity and sensitivity values exert on the likelihood of true positive and true negative. Using practical priors, high levels of confidence (99%) in results were observed when HF183 and HumM2 were used concurrently. Cumulative probability analyses showed that multiple samples from a single location can provide a >95% level of confidence in positive and negative results, suggesting that when multiple samples are necessary to account for in situ variability, a single marker can yield sufficiently reliable results.

Kidd antibodies have a reputation for causing hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. We present a case of an untransfused male patient who developed anti-Kidd(a) (Jk(a)) antibodies after receiving an allogenic renal transplant. The formation of this antibody was associated with exposure to the Kidd antigen expressed on the tubular epithelium of the transplanted kidney. The 59-year-old white male patient had received a cadaveric renal transplant at our clinic and returned 5 years later with proteinuria and elevated serum creatinine levels, consistent with nephrotic syndrome. We review the expression of Kidd antigens and the development and detection of Kidd antibodies, and discuss the case reports from the literature of Kidd antibodies associated with kidney-graft rejection that suggest Kidd antigens play a role as a minor histocompatibility antigen.

It is widely understood that stormwater drainage has a significant impact on the health of tidal creek systems via regular inputs of runoff from the surrounding watershed. Due to this hydrologic connection, contamination of the upstream drainage basin will have a direct effect on estuaries and tidal creeks that often act as receiving waters. This study focuses on the importance of drainage basin sediments as they enhance the persistence and transport of the fecal indicator bacteria E. coli within a watershed. Experiments presented use microcosm environments with drainage basin sediments and stormwater to investigate E. coli colonization of stagnant waters and to examine the importance of host sources to bacterial survival. A novel method for establishing microcosms using environmental sediments with in situ bacterial populations and sterile overlying waters is used to examine E. coli colonization of the water column in the absence of flow. Colonization of sterile sediment environments also is examined using two common host sources (human and avian). Each experiment uses sediments of varying grain size and organic content to examine the influence of physical characteristics on bacterial prevalence. Results suggest host source of bacteria may be more important to initial bacterial colonization while physical characteristics of drainage basin sediments better explains extended E. coli persistence. Findings also suggest an indirect control of water column bacterial concentration by sediment type and erodibility.