Multiple pathogen contamination of water, hands, and fomites in rural Nepal and the effect of WaSH interventions.

Water, Sanitation, and Hygiene (WaSH) interventions are the most effective in reducing diarrheal disease severity and prevalence. However, very few studies have investigated the effectiveness of WaSH intervention in reducing pathogen presence and concentration. In this study, we employed a microfluidic PCR approach to quantify twenty bacterial pathogens in water (n = 360), hands (n = 180), and fomite (n = 540) samples collected in rural households of Nepal to assess the pathogen exposures and the effect of WaSH intervention on contamination and exposure rates. The pathogen load and the exposure pathways for each pathogen in intervention and control villages were compared to understand the effects of WaSH intervention. Pathogens were detected in higher frequency and concentration from fomites samples, toilet handle (21.42%; 5.4,0 95%CI: mean log10 of 4.69, 5.96), utensils (23.5%; 5.47, 95%CI: mean log10 of 4.77, 6.77), and water vessels (22.42%; 5.53, 95%CI: mean log10 of 4.79, 6.60) as compared to cleaning water (14.36%; 5.05, 95%CI: mean log10 of 4.36, 5.89), drinking water (14.26%; 4.37, 85%CI: mean log10 of 4.37, 5.87), and hand rinse samples (16.92%; 5.49, 95%CI: mean log10 of 4.77, 6.39). There was no clear evidence that WaSH intervention reduced overall pathogen contamination in any tested pathway. However, we observed a significant reduction (p < 0.05) in the prevalence, but not concentration, of some target pathogens, including Enterococcus spp. in the intervention village compared to the control village for water and hands rinse samples. Conversely, no significant reduction in target pathogen concentration was observed for water and hand rinse samples. In swab samples, there was a reduction mostly in pathogen concentration rather than pathogen prevalence, highlighting that a reduction in pathogen prevalence was not always accompanied by a reduction in pathogen concentration. This study provides an understanding of WaSH intervention on microbe concentrations. Such data could help with better planning of intervention activities in the future.

Building Environmental and Sociological Predictive Intelligence to Understand the Seasonal Threat of SARS-CoV-2 in Human Populations.

Current modeling practices for environmental and sociological modulated infectious diseases remain inadequate to forecast the risk of outbreak(s) in human populations, partly due to a lack of integration of disciplinary knowledge, limited availability of disease surveillance datasets, and overreliance on compartmental epidemiological modeling methods. Harvesting data knowledge from virus transmission (aerosols) and detection (wastewater) of SARS-CoV-2, a heuristic score-based environmental predictive intelligence system was developed that calculates the risk of COVID-19 in the human population. Seasonal validation of the algorithm was uniquely associated with wastewater surveillance of the virus, providing a lead time of 7-14 days before a county-level outbreak. Using county-scale disease prevalence data from the United States, the algorithm could predict COVID-19 risk with an overall accuracy ranging between 81% and 98%. Similarly, using wastewater surveillance data from Illinois and Maryland, the SARS-CoV-2 detection rate was greater than 80% for 75% of the locations during the same time the risk was predicted to be high. Results suggest the importance of a holistic approach across disciplinary boundaries that can potentially allow anticipatory decision-making policies of saving lives and maximizing the use of available capacity and resources.

Influence of phosphate on bacterial release from activated carbon point-of-use filters and on biofilm characteristics.

Point-of-use (POU) filters certified to remove lead are often composed of activated carbon and have been shown to release high concentrations of bacteria, including opportunistic pathogens. In this study, we examine the impacts of the common corrosion inhibitor phosphate on biofilm characteristics and the relationship between biofilm structure and bacterial release from POU filters. This knowledge is essential for understanding how best to use the filters and where these filters fit in a system where other lead contamination prevention measures may be in place. We measured the bacterial release from activated carbon POU filters fed with groundwater - a common source of drinking water - with and without phosphate. We used optical coherence tomography (OCT) to quantitatively characterize biofilm growing on activated carbon filter material in which the biofilms were fed groundwater with and without phosphate. Phosphate filters released significantly less (57-87 %) bacteria than groundwater filters, and phosphate biofilms (median thickness: 82-331 µm) grew to be significantly thicker than groundwater biofilms (median thickness: 122-221 µm). The phosphate biofilm roughness ranged from 97 to 142 % of the groundwater biofilm roughness and was significantly greater in most weeks. Phosphate biofilms also had fewer pores per biofilm volume and shorter channels connecting those pores.

Evaluation of woodchips-amended biosand filter for nitrate and MS2 bacteriophage reduction.

In this study, two types of woodchip-amended biosand filters (Filter A sand: woodchip = 33%: 67% versus Filter B sand: woodchip = 50%: 50%, by volume) were constructed, and their abilities to remove MS2 bacteriophage and nitrate were investigated. The results indicated that Filter A and Filter B could reduce nitrate up to 40 and 36%, respectively, indicating that the nitrate reduction increased with the increase in woodchip proportion. The study underscores a positive correlation between nitrate reduction and proportional increase in woodchip content, implying the potential for fine-tuning nitrate removal by varying sand-woodchip compositions. W-BSFs could remove MS2 bacteriophage to 1.91-log10 (98.8%) by Filter A and 1.88-log10 (98.7%) by Filter B over 39 weeks. The difference in sand-woodchip proportion did not significantly impact the MS2 reduction, demonstrating that a single W-BSF can maintain its virus removal performance fairly well over a long-term period. These results indicated that the nitrate reduction could be adjusted by varying sand-woodchip contents without impacting virus removal performance. Microbial community analysis indicated that the nitrate removal by the W-BSFs could be attributed to the denitrifying bacteria, such as the family Streptomycetaceae, the genera Pseudomonas, and Bacillus, and relative abundances of the phylum Nitrospirae.

Portable, single nucleotide polymorphism-specific duplex assay for virus surveillance in wastewater.

The Argonaute protein from the archaeon Pyrococcus furiosus (PfAgo) is a DNA-guided nuclease that targets DNA with any sequence. We designed a virus detection assay in which the PfAgo enzyme cleaves the reporter probe, thus generating fluorescent signals when amplicons from a reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) assay contain target sequences. We confirmed that the RT-LAMP-PfAgo assay for the SARS-CoV-2 Delta variant produced significantly higher fluorescent signals (p < 0.001) when a single nucleotide polymorphism (SNP), exclusive to the Delta variant, was present, compared to the samples without the SNP. Additionally, the duplex assay for Pepper mild mottle virus (PMMOV) and SARS-CoV-2 detection produced specific fluorescent signals (FAM or ROX) only when the corresponding sequences were present. Furthermore, the RT-LAMP-PfAgo assay does not require dilution to reduce the impact of environmental inhibitors. The limit of detection of the PMMOV assay, determined with 30 wastewater samples, was 28 gc/µL, with a 95 % confidence interval of [11,103]. Finally, using a point-of-use device, the RT-LAMP-PfAgo assay successfully detected PMMOV in wastewater samples. Based on our findings, we conclude that the RT-LAMP-PfAgo assay can be used as a portable, SNP-specific duplex assay, which will significantly improve virus surveillance in wastewater.

Local and Environmental Reservoirs of Salmonella enterica After Hurricane Florence Flooding.

In many regions of the world, including the United States, human and animal fecal genetic markers have been found in flood waters. In this study, we use high-resolution whole genomic sequencing to examine the origin and distribution of Salmonella enterica after the 2018 Hurricane Florence flooding. We specifically asked whether S. enterica isolated from water samples collected near swine farms in North Carolina shortly after Hurricane Florence had evidence of swine origin. To investigate this, we isolated and fully sequenced 18 independent S. enterica strains from 10 locations (five flooded and five unflooded). We found that all strains have extremely similar chromosomes with only five single nucleotide polymorphisms (SNPs) and possessed two plasmids assigned bioinformatically to the incompatibility groups IncFIB and IncFII. The chromosomal core genome and the IncFIB plasmid are most closely related to environmental Salmonella strains isolated previously from the southeastern US. In contrast, the IncFII plasmid was found in environmental S. enterica strains whose genomes were more divergent, suggesting the IncFII plasmid is more promiscuous than the IncFIB type. We identified 65 antibiotic resistance genes (ARGs) in each of our 18 S. enterica isolates. All ARGs were located on the Salmonella chromosome, similar to other previously characterized environmental isolates. All isolates with different SNPs were resistant to a panel of commonly used antibiotics. These results highlight the importance of environmental sources of antibiotic-resistant S. enterica after extreme flood events.

Improved performance of nucleic acid-based assays for genetically diverse norovirus surveillance.

Nucleic acid-based assays, such as polymerase chain reaction (PCR), that amplify and detect organism-specific genome sequences are a standard method for infectious disease surveillance. However, challenges arise for virus surveillance because of their genetic diversity. Here, we calculated the variability of nucleotides within the genomes of 10 human viral species in silico and found that endemic viruses exhibit a high percentage of variable nucleotides (e.g., 51.4% for norovirus genogroup II). This genetic diversity led to the variable probability of detection of PCR assays (the proportion of viral sequences that contain the assay's target sequences divided by the total number of viral sequences). We then experimentally confirmed that the probability of the target sequence detection is indicative of the number of mismatches between PCR assays and norovirus genomes. Next, we developed a degenerate PCR assay that detects 97% of known norovirus genogroup II genome sequences and recognized norovirus in eight clinical samples. By contrast, previously developed assays with 31% and 16% probability of detection had 1.1 and 2.5 mismatches on average, respectively, which negatively impacted RNA quantification. In addition, the two PCR assays with a lower probability of detection also resulted in false negatives for wastewater-based epidemiology. Our findings suggest that the probability of detection serves as a simple metric for evaluating nucleic acid-based assays for genetically diverse virus surveillance.IMPORTANCENucleic acid-based assays, such as polymerase chain reaction (PCR), that amplify and detect organism-specific genome sequences are employed widely as a standard method for infectious disease surveillance. However, challenges arise for virus surveillance because of the rapid evolution and genetic variation of viruses. The study analyzed clinical and wastewater samples using multiple PCR assays and found significant performance variation among the PCR assays for genetically diverse norovirus surveillance. This finding suggests that some PCR assays may miss detecting certain virus strains, leading to a compromise in detection sensitivity. To address this issue, we propose a metric called the probability of detection, which can be simply calculated in silico using a code developed in this study, to evaluate nucleic acid-based assays for genetically diverse virus surveillance. This new approach can help improve the sensitivity and accuracy of virus detection, which is crucial for effective infectious disease surveillance and control.

Assessment of pathogens in flood waters in coastal rural regions: Case study after Hurricane Michael and Florence.

The severity of hurricanes, and thus the associated impacts, is changing over time. One of the understudied threats from damage caused by hurricanes is the potential for cross-contamination of water bodies with pathogens in coastal agricultural regions. Using microbiological data collected after hurricanes Florence and Michael, this study shows a dichotomy in the presence of pathogens in coastal North Carolina and Florida. Salmonella typhimurium was abundant in water samples collected in the regions dominated by swine farms. A drastic decrease in Enterococcus spp. in Carolinas is indicative of pathogen removal with flooding waters. Except for the abundance presence of Salmonella typhimurium, no significant changes in pathogens were observed after Hurricane Michael in the Florida panhandle. We argue that a comprehensive assessment of pathogens must be included in decision-making activities in the immediate aftermath of hurricanes to build resilience against risks of pathogenic exposure in rural agricultural and human populations in vulnerable locations.

Coronary "Microvascular Dysfunction": Evolving Understanding of Pathophysiology, Clinical Implications, and Potential Therapeutics.

Until recently, it has been generally held that stable angina pectoris (SAP) primarily reflects the presence of epicardial coronary artery stenoses due to atheromatous plaque(s), while acute myocardial infarction (AMI) results from thrombus formation on ruptured plaques. This concept is now challenged, especially by results of the ORBITA and ISCHEMIA trials, which showed that angioplasty/stenting does not substantially relieve SAP symptoms or prevent AMI or death in such patients. These disappointing outcomes serve to redirect attention towards anomalies of small coronary physiology. Recent studies suggest that coronary microvasculature is often both structurally and physiologically abnormal irrespective of the presence or absence of large coronary artery stenoses. Structural remodelling of the coronary microvasculature appears to be induced primarily by inflammation initiated by mast cell, platelet, and neutrophil activation, leading to erosion of the endothelial glycocalyx. This leads to the disruption of laminar flow and the facilitation of endothelial platelet interaction. Glycocalyx shedding has been implicated in the pathophysiology of coronary artery spasm, cardiovascular ageing, AMI, and viral vasculitis. Physiological dysfunction is closely linked to structural remodelling and occurs in most patients with myocardial ischemia, irrespective of the presence or absence of large-vessel stenoses. Dysfunction includes the impairment of platelet and vascular responsiveness to autocidal coronary vasodilators, such as nitric oxide, prostacyclin, and hydrogen sulphide, and predisposes both to coronary vasoconstriction and to a propensity for microthrombus formation. These findings emphasise the need for new directions in medical therapeutics for patients with SAP, as well as a wide range of other cardiovascular disorders.

Drosophila photoreceptor systems converge in arousal neurons and confer light responsive robustness.

Lateral ventral neurons (LNvs) in the fly circadian neural circuit mediate behaviors other than clock resetting, including light-activated acute arousal. Converging sensory inputs often confer functional redundancy. The LNvs have three distinct light input pathways: (1) cell autonomously expressed cryptochrome (CRY), (2) rhodopsin 7 (Rh7), and (3) synaptic inputs from the eyes and other external photoreceptors that express opsins and CRY. We explored the relative photoelectrical and behavioral input contributions of these three photoreceptor systems to determine their functional impact in flies. Patch-clamp electrophysiology measuring light evoked firing frequency (FF) was performed on large LNvs (l-LNvs) in response to UV (365 nm), violet (405 nm), blue (450 nm), or red (635 nm) LED light stimulation, testing controls versus mutants that lack photoreceptor inputs gl60j, cry-null, rh7-null, and double mutant gl60j-cry-null flies. For UV, violet, and blue short wavelength light inputs, all photoreceptor mutants show significantly attenuated action potential FF responses measured in the l-LNv. In contrast, red light FF responses are only significantly attenuated in double mutant gl60j-cry-null flies. We used a light-pulse arousal assay to compare behavioral responses to UV, violet, blue and red light of control and light input mutants, measuring the awakening arousal response of flies during subjective nighttime at two different intensities to capture potential threshold differences (10 and 400 µW/cm2). The light arousal behavioral results are similar to the electrophysiological results, showing significant attenuation of behavioral light responses for mutants compared to control. These results show that the different LNv convergent photoreceptor systems are integrated and together confer functional redundancy for light evoked behavioral arousal.

Microbial assessment of water, sanitation, and hygiene (WaSH) in temporary and permanent settlements two years after Nepal 2015 earthquake.

Disaster-induced displacement often causes people to live in temporary settlements that have limited infrastructure and access to water, sanitation, and hygiene (WaSH). Reducing the risk of diarrheal diseases in such situations requires knowing how housing influences the presence of pathogens in water and the interaction between human settlements and exposure to pathogens. A cross-sectional study was conducted in May 2017 in two communities hard-hit by the Nepal 2015 earthquake: one recovered with newly reconstructed houses, and one recovered with residents still living in sheet metal temporary shelters constructed after the earthquake. We collected 60 water (30 drinking water and 30 cleaning water), 30 hand rinse, and 90 environmental swab samples (30 toilet handles, 30 utensils, and 30 water vessels) from selected households in each location and quantified 22 bacterial pathogens using microfluidic quantitative polymerase chain reaction (mfqPCR). A total of 59 samples were randomly selected for amplicon-based sequencing of the 16S rRNA, and it identified bacterial community profiles between these two settlements and their association with target genes of pathogenic bacteria. Target genes like uidA of Escherichia coli and the mip gene of Legionella pnuemophila showed significantly high frequency in specific sample types in temporary settlements than in permanent settlements. A significantly high concentration was observed in temporary settlements for Enterococcus spp. and S. typhimurium, specifically in swab samples. There was a sharp distinction of microbial community profiles between water and hand rinse samples with environmental swab samples, with a large abundance of potentially pathogenic bacteria in swab samples in both settlements. This observation highlighted that fomite could be an important transmission route for pathogens in rural settings and designing key interventions to target different stages of transmission pathways is essential. Overall findings from this study suggest that the recovered settlement with higher quality housing may be less impacted by fecal contamination than recovering settlements and that interventions should be designed to disrupt multiple transmission pathways to reduce pathogen exposure.

RT-LAMP as Diagnostic Tool for Influenza-A Virus Detection in Swine.

Point-of-care diagnostic technologies are becoming more widely available for production species. Here, we describe the application of reverse transcription loop-mediated isothermal amplification (RT-LAMP) to detect the matrix (M) gene of influenza A virus in swine (IAV-S). M-specific LAMP primers were designed based on M gene sequences from IAV-S isolated in the USA between 2017 and 2020. The LAMP assay was incubated at 65 °C for 30 min, with the fluorescent signal read every 20 s. The assay's limit of detection (LOD) was 20 M gene copies for direct LAMP of the matrix gene standard, and 100 M gene copies when using spiked extraction kits. The LOD was 1000 M genes when using cell culture samples. Detection in clinical samples showed a sensitivity of 94.3% and a specificity of 94.9%. These results show that the influenza M gene RT-LAMP assay can detect the presence of IAV in research laboratory conditions. With the appropriate fluorescent reader and heat block, the assay could be quickly validated as a low-cost, rapid, IAV-S screening tool for use on farms or in clinical diagnostic labs.

Effects of phosphate and silicate on stiffness and viscoelasticity of mature biofilms developed with simulated drinking water.

Biofilms, a porous matrix of cells aggregated with extracellular polymeric substances under the influence of chemical constituents in the feed water, can develop a viscoelastic response to mechanical stresses. In this study, the roles of phosphate and silicate, common additives in corrosion control and meat processing, on the stiffness, viscoelasticity, porous structure networks, and chemical properties of biofilm were investigated. Three-year biofilms on PVC coupons were grown from sand-filtered groundwater with or without one of the non-nutrient (silicate) or nutrient additives (phosphate or phosphate blends). Compared with non-nutrient additives, the phosphate and phosphate-blend additives led to a biofilm with the lowest stiffness, most viscoelastic, and more porous structure, including more connecting throats with greater equivalent radii. The phosphate-based additives also led to more organic species in the biofilm matrix than the silicate additive did. This work demonstrated that nutrient additives could promote biomass accumulation but also reduce mechanical stability.

'Bushfire Season' in Australia: Determinants of Increases in Risk of Acute Coronary Syndromes and Takotsubo Syndrome.

BACKGROUND: Climate change has resulted in an increase in ambient temperatures during the summer months as well as an increase in risk of associated air pollution and of potentially disastrous bushfires throughout much of the world. The increasingly frequent combination of elevated summer temperatures and bushfires may be associated with acute increases in risks of cardiovascular events, but this relationship remains unstudied. We evaluated the individual and cumulative impacts of daily fluctuations in temperature, fine particulate matter of less than 2.5 µm (PM2.5) pollution and presence of bushfires on incidence of acute coronary syndromes and Takotsubo syndrome. METHODS: From November 1, 2019, to February 28, 2020, all admissions with acute coronary syndromes or Takotsubo syndrome to South Australian tertiary public hospitals were evaluated. Univariate and combined associations were sought among each of 1) maximal daily temperature, 2) PM2.5 concentrations, and 3) presence of active bushfires within 200 km of the hospitals concerned. RESULTS: A total of 504 patients with acute coronary syndromes and 35 with Takotsubo syndrome were studied. In isolation, increasing temperature was associated (rs = 0.26, P = .005) with increased incidence of acute coronary syndromes, while there were similar, but nonsignificant correlations for PM2.5 and presence of bushfires. Combinations of all these risk factors were also associated with a doubling of risk of acute coronary syndromes. No significant associations were found for Takotsubo syndrome. CONCLUSION: The combination of high temperatures, presence of bushfires and associated elevation of atmospheric PM2.5 concentrations represents a substantially increased risk for precipitation of acute coronary syndromes; this risk should be factored into health care planning including public education and acute hospital preparedness.

Nocturnal mosquito Cryptochrome 1 mediates greater electrophysiological and behavioral responses to blue light relative to diurnal mosquito Cryptochrome 1.

Nocturnal Anopheles mosquitoes exhibit strong behavioral avoidance to blue-light while diurnal Aedes mosquitoes are behaviorally attracted to blue-light and a wide range of other wavelengths of light. To determine the molecular mechanism of these effects, we expressed light-sensing Anopheles gambiae (AgCRY1) and Aedes aegypti (AeCRY1) Cryptochrome 1 (CRY) genes under a crypGAL4-24 driver line in a mutant Drosophila genetic background lacking native functional CRY, then tested behavioral and electrophysiological effects of mosquito CRY expression relative to positive and negative CRY control conditions. Neither mosquito CRY stops the circadian clock as shown by robust circadian behavioral rhythmicity in constant darkness in flies expressing either AgCRY1 or AeCRY1. AgCRY1 and AeCRY1 both mediate acute increases in large ventral lateral neuronal firing rate evoked by 450 nm blue-light, corresponding to CRY's peak absorbance in its base state, indicating that both mosquito CRYs are functional, however, AgCRY1 mediates significantly stronger sustained electrophysiological light-evoked depolarization in response to blue-light relative to AeCRY1. In contrast, neither AgCRY1 nor AeCRY1 expression mediates measurable increases in large ventral lateral neuronal firing rates in response to 405 nm violet-light, the peak of the Rhodopsin-7 photoreceptor that is co-expressed in the large lateral ventral neurons. These results are consistent with the known action spectra of type 1 CRYs and lack of response in cry-null controls. AgCRY1 and AeCRY1 expressing flies show behavioral attraction to low intensity blue-light, but AgCRY1 expressing flies show behavioral avoidance to higher intensity blue-light. These results show that nocturnal and diurnal mosquito Cryptochrome 1 proteins mediate differential physiological and behavioral responses to blue-light that are consistent with species-specific mosquito behavior.

Low-Cost UVBot Using SLAM to Mitigate the Spread of Noroviruses in Occupational Spaces.

Noroviruses (NoVs) cause over 90% of non-bacterial gastroenteritis outbreaks in adults and children in developed countries. Therefore, there is a need for approaches to mitigate the transmission of noroviruses in workplaces to reduce their substantial health burden. We developed and validated a low-cost, autonomous robot called the UVBot to disinfect occupational spaces using ultraviolet (UV) lamps. The total cost of the UVBOT is less than USD 1000, which is much lower than existing commercial robots that cost as much as USD 35,000. The user-friendly desktop application allows users to control the robot remotely, check the disinfection map, and add virtual walls to the map. A 2D LiDAR and a simultaneous localization and mapping (SLAM) algorithm was used to generate a map of the space being disinfected. Tulane virus (TV), a human norovirus surrogate, was used to validate the UVBot's effectiveness. TV was deposited on a painted drywall and exposed to UV radiation at different doses. A 3-log (99.9%) reduction of TV infectivity was achieved at a UV dose of 45 mJ/cm2. We further calculated the sanitizing speed as 3.5 cm/s and the efficient sanitizing distance reached up to 40 cm from the UV bulb. The design, software, and environment test data are available to the public so that any organization with minimal engineering capabilities can reproduce the UVBot system.

Predictive Intelligence for Cholera in Ukraine?

Cholera, an ancient waterborne diarrheal disease, remains a threat to public health, especially when climate/weather processes, microbiological parameters, and sociological determinants intersect with population vulnerabilities of loss of access to safe drinking water and sanitation infrastructure. The ongoing war in Ukraine has either damaged or severely crippled civil infrastructure, following which the human population is at risk of health disasters. This editorial highlights a perspective on using predictive intelligence to combat potential (and perhaps impending) cholera outbreaks in various regions of Ukraine. Reliable and judicious use of existing earth observations inspired mathematical algorithms integrating heuristic understanding of microbiological, sociological, and weather parameters have the potential to save or reduce the disease burden.

Application of neighborhood-scale wastewater-based epidemiology in low COVID-19 incidence situations.

Wastewater-based epidemiology (WBE), an emerging approach for community-wide COVID-19 surveillance, was primarily characterized at large sewersheds such as wastewater treatment plants serving a large population. Although informed public health measures can be better implemented for a small population, WBE for neighborhood-scale sewersheds is less studied and not fully understood. This study applied WBE to seven neighborhood-scale sewersheds (average population of 1471) from January to November 2021. Community testing data showed an average of 0.004 % incidence rate in these sewersheds (97 % of monitoring periods reported two or fewer daily infections). In 92 % of sewage samples, SARS-CoV-2 N gene fragments were below the limit of quantification. We statistically determined 10-2.6 as the threshold of the SARS-CoV-2 N gene concentration normalized to pepper mild mottle virus (N/PMMOV) to alert high COVID-19 incidence rate in the studied sewershed. This threshold of N/PMMOV identified neighborhood-scale outbreaks (COVID-19 incidence rate higher than 0.2 %) with 82 % sensitivity and 51 % specificity. Importantly, neighborhood-scale WBE can discern local outbreaks that would not otherwise be identified by city-scale WBE. Our findings suggest that neighborhood-scale WBE is an effective community-wide disease surveillance tool when COVID-19 incidence is maintained at a low level.

Identification of Thresholds on Population Density for Understanding Transmission of COVID-19.

Pathways of transmission of coronavirus (COVID-19) disease in the human population are still emerging. However, empirical observations suggest that dense human settlements are the most adversely impacted, corroborating a broad consensus that human-to-human transmission is a key mechanism for the rapid spread of this disease. Here, using logistic regression techniques, estimates of threshold levels of population density were computed corresponding to the incidence (case counts) in the human population. Regions with population densities greater than 3,000 person per square mile in the United States have about 95% likelihood to report 43,380 number of average cumulative cases of COVID-19. Since case numbers of COVID-19 dynamically changed each day until 30 November 2020, ca. 4% of US counties were at 50% or higher probability to 38,232 number of COVID-19 cases. While threshold on population density is not the sole indicator for predictability of coronavirus in human population, yet it is one of the key variables on understanding and rethinking human settlement in urban landscapes.

Mosquito cryptochromes expressed in Drosophila confer species-specific behavioral light responses.

Cryptochrome (CRY) is a short-wavelength light-sensitive photoreceptor expressed in a subset of circadian neurons and eyes in Drosophila that regulates light-evoked circadian clock resetting. Acutely, light evokes rapid electrical excitation of the ventral lateral subset of circadian neurons and confers circadian-modulated avoidance behavioral responses to short-wavelength light. Recent work shows dramatically different avoidance versus attraction behavioral responses to short-wavelength light in day-active versus night-active mosquitoes and that these behavioral responses are attenuated by CRY protein degradation by constant light exposure in mosquitoes. To determine whether CRY1s mediate species-specific coding for behavioral and electrophysiological light responses, we used an "empty neuron" approach and transgenically expressed diurnal Aedes aegypti (AeCRY1) versus nocturnal Anopheles gambiae (AgCRY1) in a cry-null Drosophila background. AeCRY1 is much less light sensitive than either AgCRY1 or DmCRY as shown by partial behavioral rhythmicity following constant light exposure. Remarkably, expression of nocturnal AgCRY1 confers low survival to constant white light as does expression of AeCRY1 to a lesser extent. AgCRY1 mediates significantly stronger electrophysiological cell-autonomous responses to 365 nm ultraviolet (UV) light relative to AeCRY1. AgCRY1 expression mediates electrophysiological sensitivity to 635 nm red light, whereas AeCRY1 does not, consistent with species-specific mosquito red light responses. AgCRY1 and DmCRY mediate intensity-dependent avoidance behavior to UV light at different light intensity thresholds, whereas AeCRY1 does not, thus mimicking mosquito and fly behaviors. These findings highlight CRY as a key non-image-forming visual photoreceptor that mediates physiological and behavioral light responses in a species-specific fashion.