Measuring the Utility of Surveillance Data For Monitoring the HIV/AIDS Epidemic In Sub-Saharan Africa

Since the early 1980s in sub-Saharan Africa (SSA), substantial human and financial resources have been dedicated to monitoring the HIV/AIDS epidemic. Throughout, surveillance data collected at antenatal care (ANC) clinics have been a key data source. ANC surveillance data are well-known to be biased when quantifying population HIV prevalence levels in SSA. Nonetheless, a routinely-accepted, although rarely-tested assumption has been that the data are representative of population-level HIV prevalence trends. More recently, HIV testing data from prevention of mother-to-child transmission (PMTCT) programmes have been proposed as a substitute for ANC surveillance, although these data can be subject to temporal biases too. The primary objective of this thesis is to add to the limited evidence regarding the representativeness of HIV testing data from pregnant women to monitor population-level HIV prevalence trends. Empirical analyses from repeated household-based population surveys and ANC surveillance were done for seven countries in SSA from 2000 to 2010 and among youth aged 15 to 24 years in Manicaland, Zimbabwe from 1985 to 2003. Also, a mathematical model was used to explore temporal bias in ANC surveillance trends in epidemics similar to those in Botswana, Côte d’Ivoire and rural Zimbabwe from 1985 to 2030. Finally, PMTCT programme data were assessed for their representativeness as compared to ANC surveillance data in Manicaland, Zimbabwe from 2006 to 2008. Results showed the representativeness of ANC surveillance data to vary by time period and setting, although trends among youth were more robust than those among adults aged 15 to 49 years across settings, and particularly so among men. Representativeness in the ART-era depends on coverage and scale-up, the setting, and the potential for changing fertility patterns among ART users. PMTCT data for surveillance purposes was of limited use in Manicaland, Zimbabwe from 2006 to 2008. In summary, caution is needed when using HIV testing data from pregnant women to monitor population HIV prevalence trends in SSA

The effects of item and respondent characteristics on midpoint response option endorsement: A mixed-methods study

As the demand for accountability and transparency in higher education has increased, so too has the call for direct assessment of student learning outcomes. Accompanying this increase of knowledge-based, cognitive assessments administered in a higher education context is an increased emphasis on assessing various noncognitive aspects of student growth and development over the course of their college career. Noncognitive outcomes are most often evaluated via self-report instruments associated with Likert-type response scales, posing unique challenges for researchers and assessment practitioners hoping to draw valid conclusions based upon this data. One long-debated characteristic of such assessments is the midpoint response option. More specifically, prior research suggests that respondents may be more or less likely to endorse the midpoint response option under different measurement and respondent dispositional conditions thus introducing construct-irrelevant variance within respondent scores. The current study expanded upon previous work to examine the effects of various item and respondent characteristics on endorsement and conceptualization of the midpoint response option in a noncognitive assessment context. A mixed-methods approach was employed in order to fully address research questions associated with two studies – one quantitative and one qualitative in nature. Study 1 employed hierarchical generalized linear modeling to simultaneously examine the effects of respondent characteristics and experimentally manipulated item characteristics on the probability of midpoint response option endorsement. Respondent characteristics included self-reported effort expended on the assessments administered and respondent levels of verbal aptitude (SAT verbal scores). Respondents were randomly assigned different forms of the instrument which varied in item set location (scales administered earlier versus later in the instrument) and midpoint response option label (unlabeled, neutral, undecided, neither agree nor disagree). Experimental manipulation of these variables allowed for a stronger examination of these variables’ influence and how they might interact with respondent characteristics (i.e., effort, verbal aptitude) relative to previous studies investigating the issue. Study 2 employed a think-aloud protocol to further examine and understand respondent use and conceptualization of the midpoint response option upon manipulation of midpoint response option label (unlabeled, neutral, undecided, neither agree nor disagree). Four female and four male participants were randomly selected to participate in the think-aloud process using a subset of the items administered in Study 1. Findings from both studies suggest that the midpoint response option is prone to abuse in practice. Results of Study 1 indicate that respondent characteristics, the experimental manipulation of item characteristics, and their interactions have the potential to significantly affect probability of midpoint response option endorsement. Results of Study 2 reveal that justifications provided by respondents for midpoint response endorsement are mostly construct-irrelevant and differences in conceptualization of the midpoint response option across variations in label appear to be idiosyncratic. These findings have significant implications for the validity of inferences made based upon noncognitive assessment scores and the improvement of assessment practice

Examining the role of cognitive ability and individual thinking dispositions in moral judgment

The current study examined the relation between individual cognitive ability (SAT total score), thinking dispositions (Stanovich’s (2008) Master Rationality Motive, Cacioppo et al.’s (1984) Need for Cognition, Stanovich & West’s (1997) Actively Open-minded Thinking scales), and moral judgment. The relation between these individual differences and moral judgment was examined across multiple contexts. First, the expression of myside bias was examined within a medical ethics scenario in which a limited number of organs must be allocated between two groups of people with differential transplant survival rates. Second, the role of individual differences was examined in moral reasoning across differential presentation of moral dilemma scenarios. The findings of the current study suggest that individual difference variables such as cognitive ability and thinking dispositions do not relate to moral judgment in the same manner across both experimental scenarios. Further investigation and replication is needed in order to draw definitive conclusions regarding the relation between individual cognitive ability, thinking dispositions, and moral judgment

ECONOMIC THRESHOLDS: AN APPLICATION TO FLORICULTURE

This paper introduces conjunctive optimal pest management and production decision rules applied to the floriculture industry. A grower is faced with optimally controlling multiple pests and applying cultural controls to maximize the expected net present value of benefits within a discrete time framework, subject to biological and marketing constraints.Crop Production/Industries,

OPTIMAL PEST CONTROL IN FLORICULTURE PRODUCTION OF ORNAMENTAL CROPS

We develop a conceptual bioeconomic model of floriculture production, wherein optimal decision rules depend on an intertemporal economic objective to maximize profits subject to economic and biological processes. The necessary conditions highlight intertemporal tradeoffs between aesthetic benefits and expected future net benefits of insect stocks, which have important policy implications.Research Methods/ Statistical Methods,

Assessing and adjusting for differences between HIV prevalence estimates derived from national population-based surveys and antenatal care surveillance, with applications for Spectrum 2013

Objective(s): To assess differences between HIV prevalence estimates derived from national population surveys and antenatal care (ANC) surveillance sites and to improve the calibration of ANC-derived estimates in Spectrum 2013 to more appropriately account for differences between these data. Design: Retrospective analysis of national population survey and ANC surveillance data from 25 countries with generalized epidemics in sub-Saharan Africa and 8 countries with concentrated epidemics. Methods: Adult national population survey and ANC surveillance HIV prevalence estimates were compared for all available national population survey data points for the years 1999–2012. For sub-Saharan Africa, a mixed-effects linear regression model determined whether the relationship between national population and ANC estimates was constant across surveys. A new calibration method was developed to incorporate national population survey data directly into the likelihood for HIV prevalence in countries with generalized epidemics. Results were used to develop default rules for adjusting ANC data for countries with no national population surveys. Results: ANC surveillance data typically overestimate population prevalence, although a wide variation, particularly in rural areas, is observed across countries and survey years. The new calibration method yields similar point estimates to previous approaches, but leads to an average 44% increase in the width of 95% uncertainty intervals. Conclusion: Important biases remain in ANC surveillance data for HIV prevalence. The new approach to model-fitting in Spectrum 2013 more appropriately accounts for this bias when producing national estimates in countries with generalized epidemics. In countries with concentrated epidemics, local sex ratios should be used to calibrate ANC surveillance estimates

Role of Cytolethal Distending Toxin in Altered Stool Form and Bowel Phenotypes in a Rat Model of Post-infectious Irritable Bowel Syndrome.

Background/aimsCampylobacter jejuni infection is a leading cause of acute gastroenteritis, which is a trigger for post-infectious irritable bowel syndrome (PI-IBS). Cytolethal distending toxin (CDT) is expressed by enteric pathogens that cause PI-IBS. We used a rat model of PI-IBS to investigate the role of CDT in long-term altered stool form and bowel phenotypes.MethodsAdult Sprague-Dawley rats were gavaged with wildtype C. jejuni (C+), a C. jejunicdtB knockout (CDT-) or saline vehicle (controls). Four months after gavage, stool from 3 consecutive days was assessed for stool form and percent wet weight. Rectal tissue was analyzed for intraepithelial lymphocytes, and small intestinal tissue was stained with anti-c-kit for deep muscular plexus interstitial cells of Cajal (DMP-ICC).ResultsAll 3 groups showed similar colonization and clearance parameters. Average 3-day stool dry weights were similar in all 3 groups, but day-to-day variability in stool form and stool dry weight were significantly different in the C+ group vs both controls (P < 0.01) and the CDT- roup (P < 0.01), but were not different in the CDT- vs controls. Similarly, rectal lymphocytes were significantly higher after C. jejuni (C+) infection vs both controls (P < 0.01) and CDT-exposed rats (P < 0.05). The counts in the latter 2 groups were not significantly different. Finally, c-kit staining revealed that DMP-ICC were reduced only in rats exposed to wildtype C. jejuni.ConclusionsIn this rat model of PI-IBS, CDT appears to play a role in the development of chronic altered bowel patterns, mild chronic rectal inflammation and reduction in DMP-ICC

Bridging the evidence gap: A review and research protocol for outdoor mental health therapies for young Australians

Internationally, over 60% of all lifetime cases of mental health disorders are identified as emerging by 25 years of age. In Australia, young people (aged 16–24 years) report the highest prevalence of mental health problems. Acceptability of mainstream services for young people is a concern, particularly for clients 18–25 years, heterosexual males and certain marginalised communities. With unaddressed distress in young people a precursor to poor, potentially lifelong mental ill-health trajectories, the provision of acceptable, and accessible mental health services remains a critical system imperative. Outdoor therapies, such as outdoor talking therapies, present an option for increasing the breadth of mental health interventions available to young people. Reported benefits of outdoor therapies include improved self-esteem and confidence, positive and negative affect, stress reduction and restoration, social benefits, and resilience. As outdoor therapies draw on multidisciplinary skillsets, this modality has the potential to expand services beyond existing workforce capacities. However, there are evidence gaps that must be addressed before mainstreaming of this treatment modality can occur. Here we overview the existing evidence base for outdoor talking therapies, as a form of outdoor mental healthcare, to determine their appropriateness as an effective and efficient treatment modality for young people with psychological distress in Australia and elsewhere. We then propose a research protocol designed to determine the acceptability, efficacy and efficiency of ‘outdoor talking therapies’. Our aim is to help address identified youth mental healthcare service shortages in Australia, and potentially support the health of our mental healthcare workforce

Achieving consistency in measures of HIV-1 viral suppression across countries:derivation of an adjustment based on international antiretroviral treatment cohort data

INTRODUCTION: The third of the Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 targets is to achieve a 90% rate of viral suppression (HIV viral load <1000 HIV-1 RNA copies/ml) in patients on antiretroviral treatment (ART) by 2020. However, some countries use different thresholds when reporting viral suppression, and there is thus a need for an adjustment to standardize estimates to the <1000 threshold. We aim to propose such an adjustment, to support consistent monitoring of progress towards the "third 90" target. METHODS: We considered three possible distributions for viral loads in ART patients: Weibull, Pareto and reverse Weibull (imposing an upper limit but no lower limit on the log scale). The models were fitted to data on viral load distributions in ART patients in the International epidemiology Databases to Evaluate AIDS (IeDEA) collaboration (representing seven global regions) and the ART Cohort Collaboration (representing Europe), using separate random effects models for adults and children. The models were validated using data from the World Health Organization (WHO) HIV drug resistance report and the Brazilian national ART programme. RESULTS: Models were calibrated using 921,157 adult and 37,431 paediatric viral load measurements, over 2010-2019. The Pareto and reverse Weibull models provided the best fits to the data, but for all models, the "shape" parameters for the viral load distributions differed significantly between regions. The Weibull model performed best in the validation against the WHO drug resistance survey data, while the Pareto model produced uncertainty ranges that were too narrow, relative to the validation data. Based on these analyses, we recommend using the reverse Weibull model. For example, if a country reports an 80% rate of viral suppression at <200 copies/ml, this model estimates the proportion virally suppressed at <1000 copies/ml is 88.3% (0.80(0.56) ), with uncertainty range 85.5-90.6% (0.80(0.70) -0.80(0.44) ). CONCLUSIONS: Estimates of viral suppression can change substantially depending on the threshold used in defining viral suppression. It is, therefore, important that viral suppression rates are standardized to the same threshold for the purpose of assessing progress towards UNAIDS targets. We have proposed a simple adjustment that allows this, and this has been incorporated into UNAIDS modelling software

Implementation and evaluation of a sari surveillance system in a tertiary hospital in Scotland in 2021/2022

Objective: To set up and evaluate a new surveillance system for severe acute respiratory infection (SARI) in Scotland. Study design: Cross-sectional study and evaluation of surveillance system. Methods: The SARI case definition comprised patients aged 16 years or over with an acute respiratory illness presentation requiring testing for influenza and SARS-CoV-2 and hospital admission. Data were collected from SARI cases by research nurses in one tertiary teaching hospital using a bespoke data collection tool from November 2021 to May 2022. Descriptive analyses of SARI cases were carried out. The following attributes of the surveillance system were evaluated according to Centers for Disease Control and Prevention (CDC) guidelines: stability, data quality, timeliness, positive predictive value, representativeness, simplicity, acceptability and flexibility. Results: The final surveillance dataset comprised 1163 records, with cases peaking in ISO week 50 (week ending 19/12/2021). The system produced a stable stream of surveillance data, with the proportion of SARI records with sufficient information for effective surveillance increasing from 65.4% during the first month to 87.0% over time. Similarly, the proportion where data collection was completed promptly was low initially, but increased to 50%–65% during later periods. Conclusion: SARI surveillance was successfully established in one hospital, but for a national system, additional sentinel hospital sites across Scotland, with flexibility to ensure consistently high data completeness and timeliness are needed. Data collection should be automated where possible, and demands on clinicians minimised. SARI surveillance should be embedded and resourced as part of a national respiratory surveillance strategy