Performance of a fully-automated system on a WHO malaria microscopy evaluation slide set.

BACKGROUND: Manual microscopy remains a widely-used tool for malaria diagnosis and clinical studies, but it has inconsistent quality in the field due to variability in training and field practices. Automated diagnostic systems based on machine learning hold promise to improve quality and reproducibility of field microscopy. The World Health Organization (WHO) has designed a 55-slide set (WHO 55) for their External Competence Assessment of Malaria Microscopists (ECAMM) programme, which can also serve as a valuable benchmark for automated systems. The performance of a fully-automated malaria diagnostic system, EasyScan GO, on a WHO 55 slide set was evaluated. METHODS: The WHO 55 slide set is designed to evaluate microscopist competence in three areas of malaria diagnosis using Giemsa-stained blood films, focused on crucial field needs: malaria parasite detection, malaria parasite species identification (ID), and malaria parasite quantitation. The EasyScan GO is a fully-automated system that combines scanning of Giemsa-stained blood films with assessment algorithms to deliver malaria diagnoses. This system was tested on a WHO 55 slide set. RESULTS: The EasyScan GO achieved 94.3 % detection accuracy, 82.9 % species ID accuracy, and 50 % quantitation accuracy, corresponding to WHO microscopy competence Levels 1, 2, and 1, respectively. This is, to our knowledge, the best performance of a fully-automated system on a WHO 55 set. CONCLUSIONS: EasyScan GO's expert ratings in detection and quantitation on the WHO 55 slide set point towards its potential value in drug efficacy use-cases, as well as in some case management situations with less stringent species ID needs. Improved runtime may enable use in general case management settings.

Joint effect of heatwaves and air quality on emergency department attendances for vulnerable population in Perth, Western Australia, 2006 to 2015.

BACKGROUND: As global warming and the frequency and intensity of heatwaves increases, health service utilization, including emergency department attendances (EDA) have correspondingly increased across the world. The impact of air quality on health adds to the complexity of the effects. Potential joint effects between heatwaves and air quality on EDA have been rarely reported in the literature, prompting this study. OBJECTIVES: To investigate the potential joint effect of heatwaves and air quality on the EDA for vulnerable populations in the Perth metropolitan area, Western Australia. METHODS: A time series design was used. Daily data on EDA, heatwaves (excess heat factor>0) and air pollutants (CO, SO2, NO2, O3, PM10 and PM2.5) were collected for Perth, Western Australia from 2006 to 2015. Poisson regression modelling was used to assess the associations between heatwaves, air quality, and EDA. Risk assessments on age, gender, Aboriginality, socio-economic status (SES), and joint effect between heatwaves and air quality on EDA were conducted. RESULTS: The EDA rate was higher in heatwave days (77.86/100,000/day) compared with non-heatwave days (73.90/100,000/day) with rate ratio of 1.053 (95% confidence interval 1.048, 1.058). The EDA rate was higher in males, people older than 60 years or younger than 15 years, Aboriginal people, and people with low SES. Exposure to CO, SO2, O3 and PM2.5 increased risk on EDA and exposure to PM2.5 showed joint effect with heatwave and increased risk of EDA by 6.6% after adjustment of all other risk factors. CONCLUSIONS: EDA is an important indicator to evaluate heatwave related morbidity for emergency medical service as EDA rate increased during heatwaves with relative high concentrations of air pollutants. As all air pollutants measured in the study were lower than the Australian National Standards, the joint effect of heatwaves and air quality needs to be further examined when it exceeds the standards.

Impact of elevated fine particulate matter (PM 2.5 ) during landscape fire events on cardiorespiratory hospital admissions in Perth, Western Australia.

BACKGROUND: Australia has experienced extreme fire weather in recent years. Information on the impact of fine particulate matter (PM 2.5 ) from landscape fires (LFs) on cardiorespiratory hospital admissions is limited. METHODS: We conducted a population-based time series study to assess associations between modelled daily elevated PM 2.5 at a 1.5×1.5 km resolution using a modified empirical PM 2.5 exposure model during LFs and hospital admissions for all-cause and cause-specific respiratory and cardiovascular diseases for the study period (2015-2017) in Perth, Western Australia. Multivariate Poisson regressions were used to estimate cumulative risk ratios (RR) with lag effects of 0-3 days, adjusted for sociodemographic factors, weather and time. RESULTS: All-cause hospital admissions and overall cardiovascular admissions increased significantly across each elevated PM 2.5 concentration on most lag days, with the strongest associations of 3% and 7%, respectively, at the high level of ≥12.60 µg/m3 on lag 1 day. For asthma hospitalisation, there was an excess relative risk of up to 16% (RR 1.16, 95% CI 1.00 to 1.35) with same-day exposure for all people, up to 93% on a lag of 1 day in children and up to 52% on a lag of 3 days in low sociodemographic groups. We also observed an increase of up to 12% (RR 1.12, 95% CI 1.02 to 1.24) for arrhythmias on the same exposure day and with over 154% extra risks for angina and 12% for heart failure in disadvantaged groups. CONCLUSIONS: Exposure to elevated PM 2.5 concentrations during LFs was associated with increased risks of all-cause hospital admissions, total cardiovascular conditions, asthma and arrhythmias.

Exposure to fine particulate matter (PM2.5) during landscape fire events and the risk of cardiorespiratory emergency department attendances: a time-series study in Perth, Western Australia.

BACKGROUND: Landscape fires (LFs) are the main source of elevated particulate matter (PM2.5) in Australian cities and towns. This study examined the associations between daily exposure to fine PM2.5 during LF events and daily emergency department attendances (EDA) for all causes, respiratory and cardiovascular outcomes. METHODS: Daily PM2.5 was estimated using a model that included PM2.5 measurements on the previous day, remotely sensed aerosols and fires, hand-drawn tracing of smoke plumes from satellite images, fire danger ratings and the atmosphere venting index. Daily PM2.5 was then categorised as high (≥99th percentile), medium (96th-98th percentile) and low (≤95th percentile). Daily EDA for all-cause and cardiorespiratory conditions were obtained from the Western Australian Emergency Department Data Collection. We used population-based cohort time-series multivariate regressions with 95% CIs to assess modelled daily PM2.5 and EDA associations from 2015 to 2017. We estimated the lag-specific associations and cumulative risk ratios (RR) at lags of 0-3 days, adjusted for sociodemographic factors, weather and time. RESULTS: All-cause EDA and overall cardiovascular presentations increased on all lagged days and up to 5% (RR 1.05, 95% CI 1.03 to 1.06) and 7% (RR 1.07, 95% CI 1.01 to 1.12), respectively, at the high level. High-level exposure was also associated with increased acute lower respiratory tract infections at 1 (RR 1.19, 95% CI 1.10 to 1.29) and 3 (RR 1.17, 95% CI 1.10 to 1.23) days lags and transient ischaemic attacks at 1 day (RR 1.25, 95% CI 1.02 to 1.53) and 2 (RR 1.20, 95% CI 1.01 to 1.42) days lag. CONCLUSIONS: Exposure to PM2.5 concentrations during LFs was associated with an increased risk of all-cause EDA, overall EDA cardiovascular diseases, acute respiratory tract infections and transient ischaemic attacks.

The role of mood state and emotion regulation in the discrepancy between gastrointestinal symptom burden recorded prospectively and via recall questionnaire.

BACKGROUND: There is limited empirical evidence of the magnitude of the discrepancy between prospectively recorded gastrointestinal symptom burden and that reported in recall questionnaires. Further, potential sources of the discrepancy are largely unknown. This study sought to quantify the discrepancy and to evaluate the potential role of mood disorder and emotion regulation in the discrepancy. METHODS: One hundred and forty nine subjects (mean age 20 years, 75% female) who met Rome IV criteria for irritable bowel syndrome and/or functional dyspepsia completed a 7-day prospective recording of the symptoms on a smartphone implemented ecological momentary assessment app, and then on day 8 were asked to recall their symptoms for the preceding 7 days. KEY RESULTS: Gastrointestinal symptom burden assessed by recall was exaggerated relative to that recorded prospectively. The discrepancy was moderate for overall score (Cohen d = 0.52), abdominal pain (d = 0.61) and indigestion (d = 0.49). The discrepancy was generally larger among subjects who reported a physician diagnosis of a gastrointestinal condition with d = 0.87 for overall score and d = 0.89 for abdominal pain. A number of correlations between the discrepancy and psychological traits were identified, including neuroticism with diarrhea discrepancy (r = 0.23, p = 0.004) and visceral-specific anxiety with abdominal pain discrepancy (r = -0.18, p = 0.03). There was no evidence of recency or Hawthorne (observer) effects. CONCLUSIONS AND INFERENCES: Reports of gastrointestinal symptoms obtained via recall are likely to be exaggerated relative to the actual patient experience, particularly among healthcare seekers. While psychological traits are likely to play some role, much more needs to be understood about the discrepancy.

Joint effects of heatwaves and air quality on ambulance services for vulnerable populations in Perth, western Australia.

As the frequency, intensity, and duration of heatwaves increases, emergency health serviceutilization, including ambulance service, has correspondingly increased across the world. The negative effects of air pollution on health complicate these adverse health effects. This research work is the first known study to analyze the joint effects of heatwaves and air quality on the ambulance service in Western Australia (WA). The main objective is to investigate the potential joint effects of heatwaves and air quality on the ambulance service for vulnerable populations in the Perth metropolitan area. A time series design was used. Daily data on ambulance callouts, temperature and air pollutants (CO, SO2, NO2, O3, PM10 and PM2.5) were collected for the Perth metropolitan area, WA from 2006 to 2015. Poisson regression modeling was used to assess the association between heatwaves, air quality, and ambulance callouts. Risk assessments on age, gender, socio-economic status (SES), and joint effects between heatwaves and air quality on ambulance callouts were conducted. The ambulance callout rate was higher during heatwave days (14.20/100,000/day) compared to non-heatwave days (13.95/100,000/day) with a rate ratio of 1.017 (95% confidence interval 1.012, 1.023). The ambulance callout rate was higher in males, people over 60 years old, people with low SES, and those living in coastal areas during period of heatwaves. Exposure to CO, SO2, O3 and PM2.5 increased risk on ambulance callouts and exposure to NO2 showed joint effect with heatwave and increased risk of ambulance callouts by 3% after adjustment of all other risk factors. Ambulance callouts are an important indicator for evaluating heatwave-related emergency morbidity in WA. As the median concentrations of air pollutants in WA were lower than the Australian National Standards, the interactive effects of heatwaves and air quality on ambulance service need to be further examined, especially when air pollutants exceed the standards.

Variation in Population Vulnerability to Heat Wave in Western Australia.

Heat waves (HWs) have killed more people in Australia than all other natural hazards combined. Climate change is expected to increase the frequency, duration, and intensity of HWs and leads to a doubling of heat-related deaths over the next 40 years. Despite being a significant public health issue, HWs do not attract the same level of attention from researchers, policy makers, and emergency management agencies compared to other natural hazards. The purpose of the study was to identify risk factors that might lead to population vulnerability to HW in Western Australia (WA). HW vulnerability and resilience among the population of the state of WA were investigated by using time series analysis. The health impacts of HWs were assessed by comparing the associations between hospital emergency department (ED) presentations, hospital admissions and mortality data, and intensities of HW. Risk factors including age, gender, socioeconomic status (SES), remoteness, and geographical locations were examined to determine whether certain population groups were more at risk of adverse health impacts due to extreme heat. We found that hospital admissions due to heat-related conditions and kidney diseases, and overall ED attendances, were sensitive indicators of HW. Children aged 14 years or less and those aged 60 years or over were identified as the most vulnerable populations to HWs as shown in ED attendance data. Females had more ED attendances and hospital admissions due to kidney diseases; while males had more heat-related hospital admissions than females. There were significant dose-response relationships between HW intensity and SES, remoteness, and health service usage. The more disadvantaged and remotely located the population, the higher the health service usage during HWs. Our study also found that some population groups and locations were resilient to extreme heat. We produced a mapping tool, which indicated geographic areas throughout WA with various vulnerability and resilience levels to HW. The findings from this study will allow local government, community service organizations, and agencies in health, housing, and education to better identify and understand the degree of vulnerability to HW throughout the state, better target preparatory strategies, and allocate limited resources to those most in need.

A novel modified-indirect ELISA based on spherical body protein 4 for detecting antibody during acute and long-term infections with diverse Babesia bovis strains.

BACKGROUND: Cattle persistently infected with Babesia bovis are reservoirs for intra- and inter-herd transmission. Since B. bovis is considered a persistent infection, developing a reliable, high-throughput assay that detects antibody during all stages of the infection could be pivotal for establishing better control protocols. METHODS: A modified indirect enzyme-linked immunosorbent assay (MI-ELISA) was developed using the spherical body protein-4 (SBP4) of B. bovis to detect antibody against diverse strains through all infection stages in cattle. This SBP4 MI-ELISA was evaluated for sensitivity and specificity against field sera from regions with endemic and non-endemic B. bovis. Sera were also evaluated from cattle infected experimentally with various doses and strains during acute and persistent infection with parasitemia defined by nested PCR. RESULTS: The format variables for SBP4 MI-ELISA were optimized and the cutoff for positive and negative interpretation was determined based on receiver operating characteristic curve analysis using B. bovis positive and negative sera tested in the reference immunofluorescence assay (IFA). The diagnostic specificity of the SBP4 MI-ELISA using IFA-negative sera collected from Texas was 100%, significantly higher than the cELISA (90.4%) based on an epitope in the rhoptry-associated protein-1 (RAP-1 cELISA). The diagnostic sensitivity of the SBP4 MI-ELISA was 98.7% using the IFA-positive sera collected from several areas of Mexico, in contrast to that of the RAP-1 cELISA at 60% using these same sera. In cattle infected with low and high doses of three B. bovis strains, the SBP4 MI-ELISA remained antibody positive for 11 months or more after initial detection at 10 to 13 days post-inoculation. However, the RAP-1 cELISA did not reliably detect antibody after eight months post-inoculation despite the fact that parasitemia was occasionally detectable by PCR. Furthermore, initial antibody detection by RAP-1 cELISA in low-dose infected animals was delayed approximately nine and a half days compared to the SBP4 MI-ELISA. CONCLUSIONS: These results demonstrate excellent diagnostic sensitivity and specificity of the novel SBP4 MI-ELISA for cattle with acute and long-term carrier infections. It is posited that use of this assay in countries that have B. bovis-endemic herds may be pivotal in preventing the spread of this disease to non-endemic herds.

Associations between childhood obesity and the availability of food outlets in the local environment: a retrospective cross-sectional study.

PURPOSE: Examine whether individual-level childhood obesity is related to residential availability of fast food and healthy food outlets. DESIGN: Retrospective cross-sectional study. SETTING: Perth, Western Australia. SUBJECTS: A total of 1850 children aged 5 to 15 years in 2005-2010 who participated in the Western Australian Health and Wellbeing Surveillance System survey. MEASURES: Geographical Information Systems were used to calculate a range of measures of fast food and healthy food outlet access and availability. For example, distance to nearest and access and density measures within 800 m and 3 km of each child's residence were all tested. ANALYSIS: Multivariate logistic regression analysis, controlling for individual-level sociodemographic factors and lifestyle behaviors. RESULTS: An increasing number of healthy food outlets within 800 m of a child's home was associated with a significantly reduced risk of being overweight/obese in all models tested. After controlling for age, physical activity, time spent sedentary, weekly takeaway consumption, area disadvantage, and count of fast food outlets, each additional healthy food outlet within 800 m was associated with a 20% decrease in the likelihood of a child being overweight or obese (odds ratio: .800, 95% confidence intervals: .686-.933). CONCLUSION: The local food environment around children's homes has an independent effect on child weight status. These findings highlight the importance of the built environment as a potential contributor towards child health, which should be considered when developing community health promotion programs.

Web-based geo-visualisation of spatial information to support evidence-based health policy: a case study of the development process of HealthTracks.

Place is of critical importance to health as it can reveal patterns of disease spread and clustering, associations with risk factors, and areas with greatest need for, or least access to healthcare services and promotion activities. Furthermore, in order to get a good understanding of the health status and needs of a particular area a broad range of data are required which can often be difficult and time consuming to obtain and collate. This process has been expedited by bringing together multiple data sources and making them available in an online geo-visualisation, HealthTracks, which consists of a mapping and reporting component. The overall aim of the HealthTracks project is to make spatial health information more accessible to policymakers, analysts, planners and program managers to inform decision-making across the Department of Health Western Australia. Preliminary mapping and reporting applications that have been utilised to inform service planning, increased awareness of the utility of spatial information and improved efficiency in data access were developed. The future for HealthTracks involves expanding the range of data available and developing new analytical capabilities in order to work towards providing external agencies, researchers and eventually the general public access to rich local area spatial data.