Disease Mitigation Strategies Research Articles

Shrimp Intestinal Microbiota Homeostasis: Dynamic Interplay Between the Microbiota and Host Immunity

ABSTRACTThe shrimp intestine harbors a microbiota that has pivotal roles for host's physiology. Imbalance of shrimp intestinal microbiota has been shown closely related to the occurrence of diseases. The morphological and biological features of the shrimp intestine are considered suboptimal for stable microbial colonization, making the intestinal microbiota composition highly susceptible to the impact of environmental changes or stressors, and particularly unstable. Therefore, the relative unsteadiness of the microbiota composition represents a continuous threat to host survival. Shrimp intestinal microbiota homeostasis is achieved through a dynamic interplay between the microbiota and the host's innate immunity. The shrimp intestine possesses effective innate immune mechanisms that can suppress the uncontrolled proliferation of microbiota components, and simultaneously protect the microbiota from elimination. The mechanism(s) by which the microbial components and the intestinal innate immunity interact with each other to achieve homeostasis represents an interesting interplay between host and microbiota. This review summarizes the current knowledge about intestinal microbiota colonization in shrimp, as well as the intricate mechanisms employed by the intestinal immune system to regulate this microbiota. Moreover, the potential intervention strategies to promote and protect shrimp intestinal homeostasis by modulating the microbiota are also discussed. Thus, this review seeks to comprehensively analyze the current information and contribute to a deeper understanding of the complex interplay between the shrimp intestinal microbiota and innate immunity in maintaining shrimp intestinal homeostasis and overall health. This enhanced understanding may potentially open new avenues for aquaculture management and disease mitigation strategies, ultimately benefiting the shrimp farming industry.

Projections of Aedes and Culex mosquitoes across North and South America in response to climate change

IntroductionClimate and land use change may cause the geographical range of mosquitoes to expand, shift, or contract, ultimately changing what communities are at risk for contracting mosquito-borne diseases. Across North and South America, mosquitoes from the Aedes and Culex genera are vectors for numerous diseases, including chikungunya, dengue, various equine encephalitis viruses, Saint Louis encephalitis virus, West Nile virus, yellow fever virus, and Zika virus. The goal of our study was to project the geographical distributions of important mosquito vectors across North and South America in response to climate change, which is important to inform public health planning. MethodsWe used an ecological niche model and future projections of climate and land use to project the geographical ranges of two Aedes species (Ae. aegypti, Ae. albopictus) and seven Culex species (Cx. erraticus, Cx. nigripalpus, Cx. pipiens, Cx. quinquefasciatus, Cx. restuans, Cx. salinarius, Cx. tarsalis) over North and South America in response to both a high (Shared Socioeconomic Pathway [SSP] 5, Representative Concentration Pathway [RCP] 8.5) and moderate (SSP2 RCP4.5) climate warming scenario through years 2050 and 2090. ResultsFor SSP5 RCP8.5, six species (Ae. aegypti, Ae. albopictus, Cx. erraticus, Cx. nigripalpus, Cx. quinquefasciatus, Cx. restuans) are projected to expand in geographical range, two species (Cx. pipiens, Cx. tarsalis) are projected to shift in geographical range, and one species (Cx. salinarius) is projected to nearly remain the same. Five species (Ae. aegypti, Ae. albopictus, Cx. erraticus, Cx. nigripalpus, Cx. quinquefasciatus) show the largest increase in high habitat suitability (>0.5 on a 0–1 scale) for SSP5 RCP8.5, three species (Cx. pipiens, Cx. restuans, Cx. tarsalis) show the largest increase for SSP2 RCP4.5, and one species (Cx. salinarius) shows a relatively small decrease in response to both scenarios. ConclusionsWe found that all nine species responded resiliently to climate change under both the high and moderate climate warming scenario, suggesting mosquito-borne disease is likely to be a continued threat in response to climate change. The projected geographical ranges can be used to inform disease risk analyses and mitigation strategies in response to climate change.

Navigating the Aerosolized Frontier: A Comprehensive Review of Bioaerosol Research Post-COVID-19

In the wake of the COVID-19 pandemic, the scientific community has been galvanized to unravel the enigmatic role of bioaerosols in the transmission of infectious agents. This literature review, anchored in the extensive Web of Science Core Collection database covering the period from 1990 to 2023, utilizes a bibliometric approach to chart the dynamic landscape of bioaerosol research. It meticulously documents the paradigm shifts and burgeoning areas of inquiry that have emerged in the aftermath of the pandemic. This review meticulously maps out the sources and detection strategies of pathogens in a variety of ecosystems. It clearly shows that impaction and filtration sampling methods, followed by colony counting and PCR-based detection techniques, were predominantly used in the scientific works within the previous three decades. It synthesizes the progress and limitations inherent in a range of models for predicting aerosol-mediated pathogen spread and provides a comparative analysis of eDNA technology and traditional analytical techniques for bioaerosols. The accuracy of these detection methods and forecasting models is paramount for the early recognition of transmission risks, which, in turn, paves the way for prompt and effective disease mitigation strategies. By providing a thorough analysis of the historical progression and current state of bioaerosol research, this review illuminates the path ahead, identifying the critical research needs that will drive the field’s advancement in the years to come.

In Vitro Profiling of Potential Fish Probiotics, Enterococcus hirae Strains, Isolated from Jade Perch, and Safety Properties Assessed Using Whole Genome Sequencing.

The demands of intensified aquaculture production and escalating disease prevalence underscore the need for efficacious probiotic strategies to enhance fish health. This study focused on isolating and characterising potential probiotics from the gut microbiota of the emerging aquaculture species jade perch (Scortum barcoo). Eighty-seven lactic acid bacteria and 149 other bacteria were isolated from the digestive tract of five adult jade perch. The screening revealed that 24 Enterococcus hirae isolates inhibited the freshwater pathogens Aeromonas sobria and Streptococcus iniae. Co-incubating E. hirae with the host gut suspensions demonstrated a two- to five-fold increase in the size of growth inhibition zones compared to the results when using gut suspensions from tilapia (a non-host), indicating host-specificity. Genome analysis of the lead isolate, E. hirae R44, predicted the presence of antimicrobial compounds like enterolysin A, class II lanthipeptide, and terpenes, which underlay its antibacterial attributes. Isolate R44 exhibited desirable probiotic characteristics, including survival at pH values within the range of 3 to 12, bile tolerance, antioxidant activity, ampicillin sensitivity, and absence of transferable antimicrobial resistance genes and virulence factors commonly associated with hospital Enterococcus strains (IS16, hylEfm, and esp). This study offers a foundation for sourcing host-adapted probiotics from underexplored aquaculture species. Characterisation of novel probiotics like E. hirae R44 can expedite the development of disease mitigation strategies to support aquaculture intensification.

Whole genome sequencing of drug-resistant Mycobacterium tuberculosis isolates in Victoria, Australia

ObjectivesWhole genome sequencing (WGS) can identify clusters, transmission patterns, and drug resistance mutations. This is important in low-burden settings such as Australia, as it can assist in efficient contact tracing and surveillance. MethodsWe conducted a retrospective cohort study using WGS from 155 genomically defined drug-resistant Mycobacterium tuberculosis (DR-TB) isolates collected between 2018-2021 in Victoria, Australia. Bioinformatic analysis was performed to identify resistance-conferring mutations, lineages, clusters and understand how local sequences compared with international context. ResultsOf the 155 sequences, 42% were identified as lineage 2 and 35% as lineage 1; 65.8% (102/155) were isoniazid mono-resistant, 8.4% were multi-drug resistant TB and 5.8% were pre-extensively drug-resistant / extensively drug-resistant TB. The most common mutations were observed in katG and fabG1 genes, especially at Ser315Thr and fabG1 -15 C>T for first-line drugs. Ser450Leu was the most frequent mutation in rpoB gene. Phylogenetic analysis confirmed that Victorian DR-TB were associated with importation events. There was little evidence of local transmission with only five isolate pairs. ConclusionIsoniazid-resistant TB is the commonest DR-TB in Victoria, and the mutation profile is similar to global circulating DR-TB. Most cases are diagnosed among migrants with limited transmission. This study highlights the value of WGS in identification of clusters and resistance-conferring mutations. This information is crucial in supporting disease mitigation and treatment strategies.

Raccoon spatial ecology in the rural southeastern United States.

The movement ecology of raccoons varies widely across habitats with important implications for the management of zoonotic diseases such as rabies. However, the spatial ecology of raccoons remains poorly understood in many regions of the United States, particularly in the southeast. To better understand the spatial ecology of raccoons in the southeastern US, we investigated the role of sex, season, and habitat on monthly raccoon home range and core area sizes in three common rural habitats (bottomland hardwood, upland pine, and riparian forest) in South Carolina, USA. From 2018-2022, we obtained 264 monthly home ranges from 46 raccoons. Mean monthly 95% utilization distribution (UD) sizes ranged from 1.05 ± 0.48 km2 (breeding bottomland females) to 5.69 ± 3.37 km2 (fall riparian males) and mean monthly 60% UD sizes ranged from 0.25 ± 0.15 km2 (breeding bottomland females) to 1.59 ± 1.02 km2 (summer riparian males). Males maintained home range and core areas ~2-5 times larger than females in upland pine and riparian habitat throughout the year, whereas those of bottomland males were only larger than females during the breeding season. Home ranges and core areas of females did not vary across habitats, whereas male raccoons had home ranges and core areas ~2-3 times larger in upland pine and riparian compared to bottomland hardwood throughout much of the year. The home ranges of males in upland pine and riparian are among the largest recorded for raccoons in the United States. Such large and variable home ranges likely contribute to elevated risk of zoonotic disease spread by males in these habitats. These results can be used to inform disease mitigation strategies in the southeastern United States.

103 Development of a Novel, Experimental, Minimally Invasive Model to Investigate the Genesis and Etiology of Liver Abscesses in Cattle

Abstract Most research surrounding liver abscesses involves post-hoc evaluation of naturally occurring abscesses in production settings. Few studies have been designed to experimentally induce abscesses with the purpose of identifying a time course, causality, and associated physiological implications. Therefore, we set out to develop a minimally invasive, reliable, and repeatable model to induce liver abscesses in calves in a controlled research environment to elucidate the genesis and etiology of the disease, with the ultimate goal of developing abscess reduction strategies. Experiment 1 was an attempt to induce abscesses by intraruminal inoculation with Fusobacterium necrophorum, Salmonella lubbock, and Truperella pyogenes (FST) following an intravenous lipopolysaccharide challenge. Holstein steers were harvested 3- and 10-d after inoculation, but no abscesses were detected. Experiments 2 and 3 involved diet manipulation by cycling calves on and off a high-starch, acidotic diet followed by intraruminal inoculation of microbes. In Experiment 2, Holstein calves were fed a negative control diet, an acidotic diet, and an acidotic diet plus bacterial inoculation with FST. No abscesses formed in the control or acidotic diet calves, but 43% of calves fed the acidotic diet with FST inoculation formed liver abscesses, suggesting that acidosis alone is insufficient to produce abscesses. In Experiment 3, treatments consisted of Holstein steers fed a negative control, an acidotic diet, an acidotic diet plus ruminal Fusobacterium necrophorum (F), and an acidotic diet plus Fusobacterium and Salmonella (FS). Again, there were no abscesses in the control or calves fed an acidotic diet alone; however, 40% of calves receiving F presented with an abscess, and 50% of the calves that received FS presented with abscesses. These data suggest that ruminal acidosis in conjunction with a ruminal load of pathogens commonly associated with liver abscesses provides a model that will induce liver abscesses. While the role of barrier dysfunction in the rumen and the lower gastrointestinal tract in formation of abscesses is not fully understood, this work provides a foundation to further explore the etiology of this disease and potential mitigation strategies.

The prevalence of rodent-borne zoonotic pathogens in the South Gobi desert region of Mongolia

ABSTRACT The alpine ecosystems and communities of central Asia are currently undergoing large-scale ecological and socio-ecological changes likely to affect wildlife-livestock-human disease interactions and zoonosis transmission risk. However, relatively little is known about the prevalence of pathogens in this region. Between 2012 and 2015 we screened 142 rodents in Mongolia’s Gobi desert for exposure to important zoonotic and livestock pathogens. Rodent seroprevalence to Leptospira spp. was >1/3 of tested animals, Toxoplasma gondii and Coxiella burnetii approximately 1/8 animals, and the hantaviruses being between 1/20 (Puumala-like hantavirus) and <1/100 (Seoul-like hantavirus). Gerbils trapped inside local dwellings were one of the species seropositive to Puumala-like hantavirus, suggesting a potential zoonotic transmission pathway. Seventeen genera of zoonotic bacteria were also detected in the faeces and ticks collected from these rodents, with one tick testing positive to Yersinia. Our study helps provide baseline patterns of disease prevalence needed to infer potential transmission between source and target populations in this region, and to help shift the focus of epidemiological research towards understanding disease transmission among species and proactive disease mitigation strategies within a broader One Health framework.

The Use of Machine Learning in Industry 4.0 as an Educational Tool to Address Plant Diseases for Small-Scale Farmers in Developing Countries: A Review Study

This review study aims to provide an overview of the current state of research on the use of machine learning techniques for the detection of tomato leaf diseases in the context of climate change in Zambia. Plant diseases pose significant challenges to small-scale farmers in developing countries, impacting crop yields and livelihoods. The emergence of Industry 4.0 technologies, coupled with the power of machine learning, offers promising opportunities to address these challenges and empower farmers with valuable knowledge and tools This review study aims to provide an overview of the use of machine learning in Industry 4.0 as an educational tool specifically tailored to tackle plant diseases for small-scale farmers in developing countries. The study offers insights into the potential of these techniques to enhance disease detection and contribute to sustainable agricultural practices in the face of climate change. Climate change has had significant impacts on agricultural practices worldwide, leading to the emergence and spread of various plant diseases. The study examines existing literature, research articles, and practical implementations to analyze the potential applications of machine learning in plant disease management. The review focuses on four key areas: disease identification, early detection and prediction, knowledge sharing and education, and decision support systems. With further advancements in machine learning techniques and the integration of cutting-edge technologies, the agriculture sector can benefit from improved disease detection and mitigation strategies to ensure food security in the face of climate change.

Immediate and Intermediate-Term Effects of Disease Mitigation Measures on Activity Levels as Measured by Implantable Cardiac Devices.

Routine activities of daily living are known to effect overall wellbeing, cardiovascular health, and quality of life. A decrease in daily activity level is recognized as a contributing factor to increasing rates of obesity and a decline in overall health. This study sought to evaluate the effect of disease mitigation strategies on activity level by evaluating changes in recorded cardiac parameters as measured by implantable cardiac devices for a period of time prior to and following implementation of COVID-19 mitigation efforts in Arizona. A retrospective cohort study of cardiac device data from January 1, 2019-December 31, 2020 was performed. Linear mixed-effects models with restricted maximum likelihood estimation were utilized to test for the fixed effects of Year, day, and the interaction between them. A significant decrease in daily activity minutes, daytime heart rates, and heart rate variability coincident with the initiation of disease mitigation strategies was observed. An increase in nighttime heart rates also coincided with initiation of disease mitigation strategies. These effects were noted to persist through the end of the study period. Implementation of statewide disease mitigation strategies resulted in both immediate and intermediate-term effects on activity levels, day and nighttime heart rates trends, and heart rate variability in patients with implanted cardiac devices. These data may serve useful in counseling patients regarding the importance of activity, movement, and exercise to routine health and encourage a return to pre-pandemic levels of activity.

Investigation of the individual genetic evolution of SARS-CoV-2 in a small cluster during the rapid spread of the BF.5 lineage in Tokyo, Japan.

There has been a decreasing trend in new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases and fatalities worldwide. The virus has been evolving, indicating the potential emergence of new variants and uncertainties. These challenges necessitate continued efforts in disease control and mitigation strategies. We investigated a small cluster of SARS-CoV-2 Omicron variant infections containing a common set of genomic mutations, which provided a valuable model for investigating the transmission mechanism of genetic alterations. We conducted a study at a medical center in Japan during the Omicron surge (sub-lineage BA.5), sequencing the entire SARS-CoV-2 genomes from infected individuals and evaluating the phylogenetic tree and haplotype network among the variants. We compared the mutations present in each strain within the BA.5 strain, TKYnat2317, which was first identified in Tokyo, Japan. From June 29th to July 4th 2022, nine healthcare workers (HCWs) tested positive for SARS-CoV-2 by real-time PCR. During the same period, five patients also tested positive by real-time PCR. Whole genome sequencing revealed that the infected patients belonged to either the isolated BA.2 or BA.5 sub-lineage, while the healthcare worker infections were classified as BF.5. The phylogenetic tree and haplotype network clearly showed the specificity and similarity of the HCW cluster. We identified 12 common mutations in the cluster, including I110V in nonstructural protein 4 (nsp4), A1020S in the Spike protein, and H47Y in ORF7a, compared to the BA.5 reference. Additionally, one case had the extra nucleotide-deletion mutation I27* in ORF10, and low frequencies of genetic alterations were also found in certain instances. The results of genome sequencing showed that the nine HCWs shared a set of genetic mutations, indicating transmission within the cluster. Minor mutations observed in five HCW individuals suggested the emergence of new virus variants. Five amino acid substitutions occurred in nsp3, which could potentially affect virus replication or immune escape. Intra-host evolution also generated additional mutations. The cluster exhibited a mild disease course, with individuals in this case, recovering without requiring any medical treatments. Further investigation is needed to understand the relationship between the genetic evolution of the virus and the symptoms.

Epidemic dynamics with time-varying transmission risk reveal the role of disease stage-dependent infectiousness

A key characteristic of acute communicable diseases is the infectiousness that varies over time as the infection dynamics evolve within a host, which influences the risk of transmission in different stages of the disease. Despite the evidence of time-varying transmission risk, most dynamic models of epidemics assume a constant transmission rate during the infectious period. Recent work has shown the difference in epidemic dynamics when this assumption is relaxed and different transmission rates are used by discretizing the infectious period into multiple sub-periods. Here, we develop an age-structured model to integrate a continuous time-varying transmission risk, based on an established correlation between the viral dynamics and infectiousness profile. Taking into account the natural history and parameter estimates of COVID-19 caused by the original strain of SARS-CoV-2, we demonstrate the difference in temporal epidemic dynamics when a continuous time-varying transmission probability is used as compared to multiple constant transmission probabilities. Our results show a significant difference between the incidence curves in terms of the magnitude and peak time, even when the reproduction number and total number of infections are the same for continuous and discrete transmission probabilities. Finally, we demonstrate the spurious outcome of preventing an epidemic through the isolation of infectious individuals when constant transmission probabilities are used, highlighting the importance of integrating a continuous time-dependent transmission parameter in dynamic models. These findings suggest a more cautious interpretation of model outcomes, especially those that are intended to evaluate the effectiveness of interventions and inform policy decisions for disease mitigation strategies.

Factors Related to Compliance with CDC COVID-19 Guidelines: Media Use, Partisan Identity, Science Knowledge, and Risk Assessment

The present study surveyed 970 Americans during the first two weeks of May 2020 to explore the science communication environment and the factors related to COVID-19 risk assessment and compliance with Centers for Disease Control (CDC) COVID-19 mitigation strategies. We asked respondents about the media sources used to seek information about the COVID-19 pandemic, their political identity, and general level of scientific intelligence as well as their COVID-19 specific intelligence. Controlling for demographic factors and ordinary science knowledge, we demonstrated that ordinary science COVID-19 intelligence, risk assessment, and mainstream media use were positively related to compliance with CDC guidelines for Republicans, Democrats, and Independents. Democrats’ risk perception remained at a significantly higher level than Republicans, regardless of whether they tuned in to liberal sources, conservative sources, or conservative radio/podcast shows. All media sources used for seeking COVID-19 information significantly boosted Republican-leaners’ risk perception level but that level of risk assessment never reached that of the Democrats in the sample. Independent voters decreased their compliance when using liberal media and increased their compliance when using conservative media, rejecting the more extreme positions of these media. Even occasionally listening to conservative radio/podcasts significantly decreased Democratic compliance with the public health guidelines. From the beginning of the pandemic, a polluted science communication environment was exacerbated by polarized media discussions of COVID-19, making it difficult for the public to recognize valid science, assess risk, and follow scientifically based disease mitigation strategies.

The Threat of COVID-19 on Food Security: A Modelling Perspective of Scenarios in the Informal Settlements in Windhoek

Due to the heterogeneity among households across locations, predicting the impacts of stay-at-home mitigation and lockdown strategies for COVID-19 control is crucial. In this study, we quantitatively assessed the effects of the Namibia government’s lockdown control measures on food insecurity in urban informal settlements with a focus on Windhoek, Namibia. We developed three types of conditional regression models to predict food insecurity prevalence (FIP) scenarios incorporating household frequency of food purchase (FFP) as the impacting factor, based on the Hungry Cities Food Matrix. Empirical data were derived from the 2017 African Food Security Urban Network (AFSUN) Windhoek study and applied univariate probit and bivariate partial observability models to postulate the relation between food insecurity and FFP within the context of stay-at-home disease mitigation strategy. The findings showed that FFP was positively correlated with the prevalence of food insecurity (r = 0.057, 95% CI: 0.0394, 0.085). Daily purchases portrayed a survivalist behaviour and were associated with increased food insecurity (coeff = 0.076, p = 0.05). Only those who were purchasing food twice monthly were significantly associated with reduced food insecurity (coeff = −0.201, p = 0.001). Those households in informal settlements were severely impacted by food insecurity (coeff = 0.909, p-value = 0.007). We conclude that public health compliance should precede with cash or food support to poor households in balance with the need for long-term placement of control measures to fully contain COVID-19 or related infectious diseases.

Moral Intuitions About Stigmatizing Practices and Feeding Stigmatizing Practices: How Haidt's Moral Foundations Theory Relates to Infectious Disease Stigma.

Despite extensive stigma mitigation efforts, infectious disease stigma remains common. So far, little attention has been paid to the moral psychology of stigmatizing practices (i.e. beliefs, attitudes, actions) rather than the experience of being stigmatized. Addressing the moral psychology behind stigmatizing practices seems necessary to explain the persistence of infectious disease stigma and to develop effective mitigation strategies. Our article proposes building on Jonathan Haidt's moral foundations theory, which states that moral judgements follow from intuitions rather than conscious reasoning. Conceptual analysis was conducted to show how Haidt's five moral foundations can be connected to (i) moral judgements about stigmatizing practices and (ii) stigmatizing practices themselves. We found that care/harm, fairness/cheating, loyalty/betrayal and sanctity/degradation intuitions can inform moral judgements about stigmatizing practices. Loyalty/betrayal and sanctity/degradation intuitions can sometimes also feed stigmatizing practices. Authority/subversion intuitions can inform moral judgements and stigmatizing practices towards people who disrespect authoritative rules meant to protect public health. Moral dumbfounding and posthoc reasoning might explain the persistence of stigmatizing practices. In conclusion, this study demonstrates the relevance of Haidt's approach to infectious disease stigma research and mitigation strategies. We hope that this study motivates researchers to further test and assess this approach.

Targeting Aedes aegypti Metabolism with Next-Generation Insecticides.

Aedes aegypti is the primary vector of dengue virus (DENV), zika virus (ZIKV), and other emerging infectious diseases of concern. A key disease mitigation strategy is vector control, which relies heavily on the use of insecticides. The development of insecticide resistance poses a major threat to public health worldwide. Unfortunately, there is a limited number of chemical compounds available for vector control, and these chemicals can have off-target effects that harm invertebrate and vertebrate species. Fundamental basic science research is needed to identify novel molecular targets that can be exploited for vector control. Next-generation insecticides will have unique mechanisms of action that can be used in combination to limit selection of insecticide resistance. Further, molecular targets will be species-specific and limit off-target effects. Studies have shown that mosquitoes rely on key nutrients during multiple life cycle stages. Targeting metabolic pathways is a promising direction that can deprive mosquitoes of nutrition and interfere with development. Metabolic pathways are also important for the virus life cycle. Here, we review studies that reveal the importance of dietary and stored nutrients during mosquito development and infection and suggest strategies to identify next-generation insecticides with a focus on trehalase inhibitors.

The rising threat of geminiviruses: molecular insights into the disease mechanism and mitigation strategies.

Geminiviruses are among the most threatening emerging plant viruses, accountable for a huge loss to agriculturalproduction worldwide. These viruses have been responsible for some serious outbreaks during the last fewdecades across different parts of the world. Sincere efforts have been made to regulate the disease incidence by incorporating a multi-dimensional approach, and this process has been facilitated greatly by the advent of moleculartechniques. But, the mixed infection due to the polyphagous nature of vectors results in viral recombinationfollowed by the emergence of novel viral strains which thus renders the existing mitigation strategies ineffective.Hence, a multifaceted insight into the molecular mechanism of the disease is really needed to understand theregulatory points; much has been done in this direction during the last few years. The present review aims toexplore all the latest developments made so far and to organize the information in a comprehensive manner so thatsome novel hypotheses for controlling the disease may be generated. Starting with the background information, diverse genera of geminiviruses are listed along with their pathologicaland economic impacts. A comprehensive and detailed mechanism of infection is elaborated to study theinteractions between vector, host, and virus at different stages in the life cycle of geminiviruses. Finally, an effort isalso made to analyze the progress made at the molecular level for the development of various mitigation strategiesand suggest more effective and better approaches for controlling the disease. The study has provided a thorough understanding of molecular mechanism of geminivirus infection.

Quantifying the presymptomatic transmission of COVID-19 in the USA.

The emergence of many presymptomatic hidden transmission events significantly complicated the intervention and control of the spread of COVID-19 in the USA during the year 2020. To analyze the role that presymptomatic infections play in the spread of this disease, we developed a state-level metapopulation model to simulate COVID-19 transmission in the USA in 2020 during which period the number of confirmed cases was more than in any other country. We estimated that the transmission rate (i.e., the number of new infections per unit time generated by an infected individual) of presymptomatic infections was approximately 59.9% the transmission rate of reported infections. We further estimated that {at any point in time the} average proportion of infected individuals in the presymptomatic stage was consistently over 50% of all infected individuals. Presymptomatic transmission was consistently contributing over 52% to daily new infections, as well as consistently contributing over 50% to the effective reproduction number from February to December. Finally, non-pharmaceutical intervention targeting presymptomatic infections was very effective in reducing the number of reported cases. These results reveal the significant contribution that presymptomatic transmission made to COVID-19 transmission in the USA during 2020, as well as pave the way for the design of effective disease control and mitigation strategies.

Rapid molecular assays for the detection of the four dengue viruses in infected mosquitoes.

The pantropic emergence of severe dengue disease can partly be attributed to the co-circulation of different dengue viruses (DENVs) in the same geographical location. Effective monitoring for circulation of each of the four DENVs is critical to inform disease mitigation strategies. In low resource settings, this can be effectively achieved by utilizing inexpensive, rapid, sensitive and specific assays to detect viruses in mosquito populations. In this study, we developed four rapid DENV tests with direct applicability for low-resource virus surveillance in mosquitoes. The test protocols utilize a novel sample preparation step, a single-temperature isothermal amplification, and a simple lateral flow detection. Analytical sensitivity testing demonstrated tests could detect down to 1,000 copies/µL of virus-specific DENV RNA, and analytical specificity testing indicated tests were highly specific for their respective virus, and did not detect closely related flaviviruses. All four DENV tests showed excellent diagnostic specificity and sensitivity when used for detection of both individually infected mosquitoes and infected mosquitoes in pools of uninfected mosquitoes. With individually infected mosquitoes, the rapid DENV-1, -2 and -3 tests showed 100% diagnostic sensitivity (95% CI = 69% to 100%, n=8 for DENV-1; n=10 for DENV 2,3) and the DENV-4 test showed 92% diagnostic sensitivity (CI: 62% to 100%, n=12) along with 100% diagnostic specificity (CI: 48-100%) for all four tests. Testing infected mosquito pools, the rapid DENV-2, -3 and -4 tests showed 100% diagnostic sensitivity (95% CI = 69% to 100%, n=10) and the DENV-1 test showed 90% diagnostic sensitivity (55.50% to 99.75%, n=10) together with 100% diagnostic specificity (CI: 48-100%). Our tests reduce the operational time required to perform mosquito infection status surveillance testing from > two hours to only 35 minutes, and have potential to improve accessibility of mosquito screening, improving monitoring and control strategies in low-income countries most affected by dengue outbreaks.

Camp health care practices and adaptations associated with COVID-19

ABSTRACT The COVID-19 pandemic caused significant changes in camp health care implementation. This study evaluated camp providers’ COVID-19 management practices following the summer of 2021 to inform future communicable disease planning. Online questionnaire data were collected from camp leaders and health care providers (n = 321). Reported COVID-19 cases were very low among both campers and staff. Most camps encouraged camper and staff vaccination before camp, with only a quarter requiring staff vaccination. NPIs used most frequently included cohorting, enhanced cleaning procedures, and scheduled hand hygiene. Camps also reduced the number of campers served and relocated dining, camp health care, and other activities outdoors. A positive correlation was found between requiring staff COVID vaccination and no positive COVID-19 cases. These findings offer insight into communicable disease mitigation strategies and organizational planning that can continue to keep camp populations healthy during communicable disease events like COVID-19.