Effects of Vector Maturation Time on the Dynamics of Cassava Mosaic Disease

Many plant diseases are caused by plant viruses that are often transmitted to plants by vectors. For instance, the cassava mosaic disease, which is spread by whiteflies, has a significant negative effect on plant growth and development. Since only mature whiteflies can contribute to the spread of the cassava mosaic virus, and the maturation time is non-negligible compared to whitefly lifetime, it is important to consider the effects this maturation time can have on the dynamics. In this paper, we propose a mathematical model for dynamics of cassava mosaic disease that includes immature and mature vectors and explicitly includes a time delay representing vector maturation time. A special feature of our plant epidemic model is that vector recruitment is negatively related to the delayed ratio between vector density and plant density. We identify conditions of biological feasibility and stability of different steady states in terms of system parameters and the time delay. Numerical stability analyses and simulations are performed to explore the role of various parameters, and to illustrate the behaviour of the model in different dynamical regimes. We show that the maturation delay may stabilise epidemiological dynamics that would otherwise be cyclic.

The role of infrared dermal thermometry in the management of neuropathic diabetic foot ulcers

AIM

This prospective observational study evaluated the role of infrared (IR) dermal thermometry in the management of diabetic foot ulcers.

METHODS

Thirty participants with unilateral neuropathic diabetic foot ulcers of University of Texas grade 1 or 2 (stage A) were followed up monthly for 1 year. At each visit, skin temperatures were measured with an IR dermal thermometer at corresponding sites on both feet, using the contralateral feet without ulcers as controls.

RESULTS

Average temperature and ulcer temperature in affected feet were significantly higher than in unaffected feet, with a mean difference of 1.2 °C [95% confidence interval (CI) 0.7 to 1.7] and 3.1 °C (95% CI 2.3 to 3.9), respectively. Although the gradient between average temperature of affected foot and that of unaffected foot normalized (mean difference 0.2 °C, 95% CI -0.2 to 0.7) at healing, the temperature gradient between the ulcer and a corresponding site on the unaffected foot decreased but did not normalize (mean difference 2.1 °C, 95% CI 1.2 to 3.1) even at healing, as documented by skin closure, and persisted for up to 1 month after skin closure. A gradient of ≥1 °C between average temperature of affected foot and that of unaffected foot at initial presentation or at any time during ulcer healing was found to predict impaired healing and should alert clinicians to ulcers requiring more attention. An incremental trend in temperature gradient (median difference 2.2 °C; range 0.1-6.3 °C) at a site on the foot was predictive of a recurrent ulcer involving the same site.

CONCLUSIONS

IR dermal thermometry may have a role in predicting diabetic foot ulcer healing, in determining the completeness of healing and in guiding the duration of offloading. Serial monitoring of the temperature gradient may predict the development of recurrent diabetic foot ulcers.

Discrepancies between the decisions of an endocarditis team and the modified Duke's Criteria for the diagnosis of infective endocarditis

Background/Introduction

The 2015 ESC endocarditis guidelines recommend that a multi-disciplinary endocarditis team should be involved in caring for patients with endocarditis. This approach recognises the heterogeneity of infective endocarditis, and the difficulty in distinguishing endocarditis from other infective and non-infective diseases.

Purpose

This study looks at suspected cases of infective endocarditis discussed at the endocarditis MDT, discrepancies between MDT outcome and the modified Duke's criteria in diagnosing endocarditis, and number of referrals to MDT over time.

Methods

Patients were identified by review of MDT outcome forms. Demographic data, predisposing conditions, imaging findings, microbiology results and final diagnosis were identified by reviewing MDT forms and electronic charts.

Results

234 patients were identified from MDT outcome forms. 118 (50.4%) patients were over 65, 165 (70.5%) were male, and 65 (27.8%) had previous valve surgery. Crosstabulation of MDT decision against outcome by modified Duke's criteria are seen in Table 1. The endocarditis team identified 7 patients with definite or possible endocarditis who were excluded by applying the modified Duke's criteria. 1 of these patients required aortic valve replacement. 2 patients with disseminated Staphylococcal infections without endocarditis were classed as definite endocarditis by the modified Duke's criteria. Referral data and outcomes are included in Figure 1.

Conclusions

The endocarditis team can be used to improve the sensitivity and specificity of the modified Duke's criteria. As the endocarditis team became established the volume of referrals has increased, along with the number of patients who have alternate diagnoses. Practitioners should bear this in mind when establishing endocarditis teams.

Figure 1. Referrals over time by outcome

Funding Acknowledgement

Type of funding source: None

Changes in access to educational and healthcare services for individuals with intellectual and developmental disabilities during COVID-19 restrictions

BACKGROUND

COVID-19 restrictions have significantly limited access to in-person educational and healthcare services for all, including individuals with intellectual and developmental disabilities (IDDs). The objectives of this online survey that included both national and international families were to capture changes in access to healthcare and educational services for individuals with IDDs that occurred shortly after restrictions were initiated and to survey families on resources that could improve services for these individuals.

METHODS

This was an online survey for caregivers of individuals with (1) a genetic diagnosis and (2) a neurodevelopmental diagnosis, including developmental delay, intellectual disability, autism spectrum disorder or epilepsy. The survey assessed (1) demographics, (2) changes in access to educational and healthcare services and (3) available and preferred resources to help families navigate the changes in service allocation.

RESULTS

Of the 818 responses (669 within the USA and 149 outside of the USA), most families reported a loss of at least some educational or healthcare services. Seventy-four per cent of parents reported that their child lost access to at least one therapy or education service, and 36% of respondents lost access to a healthcare provider. Only 56% reported that their child received at least some continued services through tele-education. Those that needed to access healthcare providers did so primarily through telemedicine. Telehealth (both tele-education and telemedicine) was reported to be helpful when available, and caregivers most often endorsed a need for an augmentation of these remote delivery services, such as 1:1 videoconference sessions, as well as increased access to 1:1 aides in the home.

CONCLUSIONS

COVID-19 restrictions have greatly affected access to services for individuals with syndromic IDDs. Telehealth may provide opportunities for delivery of care and education in a sustainable way, not only as restrictions endure but also after they have been lifted.

Mobile Teaching Kitchen Project – eradicating and preventing malnutrition through nutrition education

Background

Global malnutrition, affecting over 2.6 billion people globally, represents a triple burden to health in the form of micronutrient deficiencies, under-and over-nutrition. Malnutrition reaches all parts of society, with those undernourished and deficient in vitamins and minerals often thought to be the poorer in society, whilst overnourished those wealthier. NNEdPro, an international think-tank working to develop nutrition capacity, performed a landscaping activity in Kolkata, India and noted significant undernutrition within the slum dwelling population and overnutrition among the inner-city workers.

Results

NNEdPro' s Mobile Teaching Kitchen (MTK) project was developed as a nutritional education tool to improve awareness of diet diversity and disease prevention amongst marginalised communities by using locally sourced foods and cooking skills. Local volunteers trained in healthy cooking transfers core principles through cooking demonstrations of sustainable, nutritional, and affordable meals. They follow a 'See One, Do One, Teach One' (S1D1T1) model to transfer knowledge to their peers. This model aims to create a sustainable solution that will enable the rural-urban slum dwellers across regions of the world to challenge food insecurity and malnutrition.

Conclusions

The potential of the Teaching Kitchen can extend beyond creating powerful behavior change for improved health and nutrition within local communities of both developing and developed countries. In addition to improving the wellbeing of the community, the project can also potentially create livelihood opportunities through empowering women with catering skills and having a positive impact on the health and nutritional status of the wider community. After successful impacts in India, the Mobile Teaching Kitchen model has been proposed to other 8 existing regional networks of NNEdPro such as Australia & New Zealand, Brazil, Italy, Mexico, Morocco, Switzerland, USA, and UK.

Use of Machine Learning and Artificial Intelligence to predict SARS-CoV-2 infection from Full Blood Counts in a population

Since December 2019 the novel coronavirus SARS-CoV-2 has been identified as the cause of the pandemic COVID-19. Early symptoms overlap with other common conditions such as common cold and Influenza, making early screening and diagnosis are crucial goals for health practitioners. The aim of the study was to use machine learning (ML), an artificial neural network (ANN) and a simple statistical test to identify SARS-CoV-2 positive patients from full blood counts without knowledge of symptoms or history of the individuals. The dataset included in the analysis and training contains anonymized full blood counts results from patients seen at the Hospital Israelita Albert Einstein, at São Paulo, Brazil, and who had samples collected to perform the SARS-CoV-2 rt-PCR test during a visit to the hospital. Patient data was anonymised by the hospital, clinical data was standardized to have a mean of zero and a unit standard deviation. This data was made public with the aim to allow researchers to develop ways to enable the hospital to rapidly predict and potentially identify SARS-CoV-2 positive patients. We find that with full blood counts random forest, shallow learning and a flexible ANN model predict SARS-CoV-2 patients with high accuracy between populations on regular wards (AUC = 94-95%) and those not admitted to hospital or in the community (AUC = 80-86%). Here, AUC is the Area Under the receiver operating characteristics Curve and a measure for model performance. Moreover, a simple linear combination of 4 blood counts can be used to have an AUC of 85% for patients within the community. The normalised data of different blood parameters from SARS-CoV-2 positive patients exhibit a decrease in platelets, leukocytes, eosinophils, basophils and lymphocytes, and an increase in monocytes. SARS-CoV-2 positive patients exhibit a characteristic immune response profile pattern and changes in different parameters measured in the full blood count that are detected from simple and rapid blood tests. While symptoms at an early stage of infection are known to overlap with other common conditions, parameters of the full blood counts can be analysed to distinguish the viral type at an earlier stage than current rt-PCR tests for SARS-CoV-2 allow at present. This new methodology has potential to greatly improve initial screening for patients where PCR based diagnostic tools are limited.

Cardiological society of India document on safety measure during echo evaluation of cardiovascular disease in the time of COVID-19

An echocardiographic investigation is one of the key modalities of diagnosis in cardiology. There has been a rising presence of cardiological comorbidities in patients positive for COVID-19. Hence, it is becoming extremely essential to look into the correct safety precautions, healthcare professionals must take while conducting an echo investigation. The decision matrix formulated for conducting an echocardiographic evaluation is based on presence or absence of cardiological comorbidity vis-à-vis positive, suspected or negative for COVID-19. The safety measures have been constructed keeping in mind the current safety precautions by WHO, CDC and MoHFW, India.

Cardiological Society of India: Document on acute MI care during COVID-19

The unprecedented and rapidly spreading Coronavirus Disease-19 (COVID-19) pandemic has challenged public health care systems globally. Based on worldwide experience, India has initiated a nationwide lockdown to prevent the exponential surge of cases. During COVID-19, management of cardiovascular emergencies like acute Myocardial Infarction (MI) may be compromised. Cardiological Society of India (CSI) has ventured in this moment of crisis to evolve a consensus document for care of acute MI. However, this care should be individualized, based on local expertise and governmental advisories.

The association of dietary patterns and carotid intima-media thickness: A synthesis of current evidence

AIMS

Dietary pattern (DP) analysis has emerged as a holistic method to understand the effects of food intake on health outcomes. Though dietary intake has been associated with cardiovascular disease, the association of DPs and carotid intima-media thickness (CIMT), a robust early marker of cardiovascular disease progression has not been comprehensively investigated. This study systematically explores the association of a posteriori and a priori DPs and CIMT.

DATA SYNTHESIS

Through a systematic search of MEDLINE, CINAHL, and Web of Science, twenty studies that derived DPs using a posteriori or a priori methods with CIMT as an outcome were included. Four cross-sectional studies and 1 cohort paper reported a statistically significant association between increased consumption of 'unhealthy' foods (i.e processed meat, soda drinks and refined grain) and increased CIMT. While four cross-sectional studies reported a statistically significant association of DPs characterized by increased consumption of 'healthy' foods (i.e fruit and vegetables, fish) and decreased CIMT. DPs derived from each study varied depending on derivation method, study design and use of dietary data collection method.

CONCLUSION

Findings from this review are generally supportive of a trend between DPs with higher consumption of 'healthy' foods and lower consumption of 'unhealthy' foods and decreased CIMT; however, the association was largely not statistically significant. Evidence was overwhelmingly heterogeneous due to differences seen in DPs based on location and culture, sample characteristics and adjustment for confounders. Long-term prospective observational and interventional studies with standardized sample selection and dietary data collection are needed to significantly establish the role of DPs on CIMT.

P3779NT-proBNP adds incremental predictive information on incident atrial fibrillation in patients with asymptomatic aortic stenosis

Background

Incident atrial fibrillation (AF) marks an adverse shift in the prognosis of patients with aortic stenosis (AS). Identifying risk factors for AF is therefore of paramount importance for timely intervention in patients with AS. In patients without AS, brain natriuretic peptides (BNP) is a well-established biomarker for left ventricular pressure overload on the pathway to heart failure and atrial fibrillation. However, a potential role of NT-proBNP to predict risk of new-onset AF in asymptomatic patients with mild to moderate AS is not well studied.

Methods

We included 1,434 patients with mild to moderate AS from the SEAS Study (Simvastatin and Ezetimibe in Aortic Stenosis) without AF or clinically overt heart failure at baseline. The primary endpoint for this substudy was time to incident AF, as determined by the first annual in-study 12-lead ECG with AF. Multivariable Cox model were adjusted for other important predictors of incident AF as selected by Bayesian statistics. Fine and Gray competing risk regression was used to evaluate the influence of all-cause mortality on selected predictor variables of incident AF.

Results

During a median follow-up of 4.3 years (range 0.1–6.9 years), incident AF occurred in 114 (6.1%) patients (13.8 per 1,000 person-years of follow-up), who at baseline were older (69±10 vs. 67±10 years, p<0.001), had larger systolic left atrial diameter (46±24 vs. 34±18 mm, p<0.001) and higher NT-proBNP level (286 [132; 613] vs. 154 [82; 297] pg/ml, p<0.001); but same left ventricular ejection fraction (66±6 mm vs. 67±6, p=0.4). In multivariable Cox regression, adjusted for age, circumferential end-systolic stress, left atrial volume and ECG PR interval, Ln(NT-proBNP) was associated with higher risk of new-onset AF (HR: 1.9 [95% CI: 1.6–2.3], p<0.001). Similar results were found when using Fine and Gray estimates with all-cause mortality (HR: 2.0 [95% CI: 1.7–2.4], p<0.001 (Figure, panel A). NT-proBNP level added incremental predictive information on incident AF over the other important, as selected by Bayesian statistics, predictor variables (C-index 0.81, p<0.001, Figure, panel B). There was no interaction with aortic valve area (p>0.05).

Figure 1

Conclusions

In patients with asymptomatic aortic stenosis and sinus rhythm at baseline, NT-proBNP levels were significantly higher in patients who subsequently developed AF. NT-proBNP significantly improved prognostic information of incident AF over other important predictor variables. This supports the notion that incident AF is a marker of left ventricular pressure overload and possibly a novel marker of timely intervention with aortic valve replacement.

Outcomes of surgery for post-cholecystectomy bile duct injuries: An audit from a tertiary referral center

AIM OF THE STUDY

Bile duct injury (BDI) after cholecystectomy is a serious complication. It often requires surgical repair. The aim of this study was to report on the short and long-term outcomes of surgery for post-cholecystectomy BDI.

PATIENTS AND METHODS

All the patients, who underwent surgery for post-cholecystectomy BDI between August 2007 and September 2017, were retrospectively reviewed. McDonald grading system was used to assess the long-term outcome. The risk factors for unsatisfactory long-term outcome were analyzed by univariate and multivatiate logistic regression analysis.

RESULTS

In total, 228 patients had a Roux-en-Y hepaticojejunostomy. Open cholecystectomy was the major cause of BDI (61%). The median time from injury to definitive repair was 6 months. The types of BDI were as follows: E1 in 13 (5.7%), E2 in 68 (29.82%), E3 in 108 (47.36%), E4 in 28 (12.28%), and E5 in 11 (4.82%) patients respectively. Postoperative morbidity and mortality were 25% and 1.31% respectively. After a median follow-up of 58 months, 90% patients had excellent to good outcome. Recurrent stricture developed in 6 (3%) patients. On multivariate analysis, long injury-repair interval and previous attempt at repair were independent predictors for unsatisfactory long-term outcome.

CONCLUSION

Surgical reconstruction affords excellent to good results for majority of the patients with post-cholecystectomy BDI. As longer delay in definitive repair and previous attempt at repair were associated with unsatisfactory long-term outcome, early referral to a specialized hepatobiliary surgery unit is recommended.

A23 Population level diversification of hepatitis C viral strains over time among people who inject drugs in Baltimore, MD

Hepatitis C virus (HCV) infection occurs in 30–90 per cent of people who inject drugs (PWID). Although cure rates can exceed 95 per cent, treatment access is limited and approximately 400,000 people die each year due to complications of chronic infection. A temporal analysis of cluster networks among PWID can be used to inform strategies to interdict transmission. In Baltimore, PWID have been recruited for The AIDS Linked to the IntraVenous Experience (ALIVE) cohort. A demographic questionnaire was administered and recorded for baseline and recent participants. Viral RNA underwent PCR with primers targeting the core and envelope-1 protein (CE1) and sequenced via Sanger sequencing. Sequences with > 400 bp reads and Q-scores >370 were used for downstream analysis resulting in 322 ALIVE baseline participants (1988–9) and 548 recently diagnosed subjects enrolled approximately two decades later (2005–16). Cluster networks were rendered with a threshold of 4 per cent in MicrobeTRACE, and statistical analyses were performed in R Studio. Of the 1988–9 subjects, the majority (259/317, 81.7%) were a part of cluster. There were nine clusters and fifty-eight singletons, with two large clusters containing most sequences of genotype 1a (73.5%). Two decades later, a minority of recently diagnosed individuals (235/512, 44.1%) were part of a cluster. There were seventeen clusters with 286 singletons with two large clusters containing 1a genotype individuals (21.5%). Additional clustering was done by parsing the two datasets by subtype 1a (n = 714) and 1b (n = 151). The genotype 1a network demonstrates a majority, 65.8 per cent, of participants in clusters. Moreover, two large clusters can be observed with baseline participants towards the center and recent participants on the outskirts indicative of high linkage at baseline. The genotype 1b network produced a single large cluster but subclusters were observed. The sequences between the two time points co-mingled but subclusters were also observed. Interestingly, the two large clusters from 1988 to 1989 were still evident in the 2005–16 viral sequences. We observed greater cluster diversity in more recently diagnosed individuals, indicative of a less connected network of individuals sharing transmission risk, though major viral strains did persist over time in this cohort.

One-Dimensional Quasicrystals with Power-Law Hopping

One-dimensional quasiperiodic systems with power-law hopping, 1/r^{a}, differ from both the standard Aubry-André (AA) model and from power-law systems with uncorrelated disorder. Whereas in the AA model all single-particle states undergo a transition from ergodic to localized at a critical quasidisorder strength, short-range power-law hops with a>1 can result in mobility edges. We find that there is no localization for long-range hops with a≤1, in contrast to the case of uncorrelated disorder. Systems with long-range hops rather present ergodic-to-multifractal edges and a phase transition from ergodic to multifractal (extended but nonergodic) states. Both mobility and ergodic-to-multifractal edges may be clearly revealed in experiments on expansion dynamics.

Establishment of a clinically relevant large animal model to assess the healing of metaphyseal bone

Despite the high incidence of metaphyseal bone fractures in patients, the mechanisms underlying the healing processes are poorly understood due to the lack of suitable experimental animal models. Hence, the present study was conducted to establish and characterise a clinically relevant large-animal model for metaphyseal bone healing. Six female adult Merino sheep underwent full wedge-shaped osteotomy at the distal left femur metaphysis. The osteotomy was stabilised internally with a customised anatomical locking titanium plate that allowed immediate post-operative full-weight bearing. Bone healing was evaluated at 12 weeks post-fracture relative to the untouched right femur. Histological and quantitative micro-computed tomography results revealed an increased mineralised bone mass with a rich bone microarchitecture. New trabeculae healed by direct intramembranous ossification, without callus and cartilaginous tissue formation. Stiffness at the cortical and trabecular regions was comparable in both groups. Functional morphological analysis of the osteocyte lacunae revealed regularly arranged spherically shaped lacunae along with the canalicular network. Bone surface biochemical analysis using time-of-flight secondary-ion mass spectrometry showed high and homogeneously distributed levels of calcium and collagenous components. Ultrastructure imaging of the new trabeculae revealed a characteristic parallel arrangement of the collagen fibrils, evenly mineralised by the dense mineral substance. The specialised bone cells were also characterised by their unique structural features. Bone remodelling in the fractured femur was evident in the higher expression levels of prominent bone formation and resorption genes. In conclusion, the novel metaphyseal fracture model is beneficial for studying healing and treatment options for the enhancement of metaphyseal bone defects.

Zika and travel in the news: a content analysis of US news stories during the outbreak in 2016-2017

OBJECTIVES

This study aimed to understand what information the US media communicated about Zika virus (ZIKV) and travel in 2016 and 2017.

STUDY DESIGN

We conducted a content analysis of news coverage about ZIKV and travel from April 5, 2016 to March 31, 2017.

METHODS

We obtained a stratified, random sample of English language, US print newspaper and television news coverage about ZIKV and travel. We developed a coding scheme to assess key messages in the news, including how ZIKV is transmitted, the symptoms and outcomes of ZIKV infection, and recommended prevention behaviors.

RESULTS

Almost all news stories mentioned mosquito-borne transmission (96.8%) and just over half mentioned sexual transmission (55.3%). News stories were more likely to talk about ZIKV outcomes (78.8%) than ZIKV symptoms (40.6%). However, outcomes affecting babies were mentioned more frequently than outcomes affecting adults. Recommendations included a wide array of protective behaviors, such as delaying or avoiding travel (77.6%) and using mosquito repellent (41.0%). However, few studies (10.9%) mentioned barriers to practicing ZIKV prevention behaviors.

CONCLUSIONS

Public health organizations and professionals can use these findings to help improve communication about future outbreaks of mosquito-borne illnesses. We also recommend conducting real-time monitoring of news media and frequent content analysis of news stories to ensure coverage provides the information the public needs.