Calculation of the age of the first infection for skin sores and scabies in five remote communities in northern Australia

Prevalence of skin sores and scabies in remote Australian Aboriginal communities remains unacceptably high, with Group A Streptococcus (GAS) the dominant pathogen. We aim to better understand the drivers of GAS transmission using mathematical models. To estimate the force of infection, we quantified the age of first skin sores and scabies infection by pooling historical data from three studies conducted across five remote Aboriginal communities for children born between 2001 and 2005. We estimated the age of the first infection using the Kaplan–Meier estimator; parametric exponential mixture model; and Cox proportional hazards. For skin sores, the mean age of the first infection was approximately 10 months and the median was 7 months, with some heterogeneity in median observed by the community. For scabies, the mean age of the first infection was approximately 9 months and the median was 8 months, with significant heterogeneity by the community and an enhanced risk for children born between October and December. The young age of the first infection with skin sores and scabies reflects the high disease burden in these communities.We acknowledge the Lowitja Institute and the Cooperative Research Centre for Aboriginal Health who originally funded and lent significant support to the EAHSP. M. J. Lydeamore is funded by an Australian Postgraduate Research Training Program Scholarship; This work is supported by an NHMRC Project Grant titled ‘Optimising intervention strategies to reduce the burden of Group A Streptococcus in Aboriginal Communities’ (GNT1098319). We thank the NHMRC Centre for Research Excellence in Infectious Diseases Modelling to Inform Public Health Policy (GNT1078068). J. McVernon is supported by an NHMRC Principal Research Fellowship (GNT1117140). S. Tong is supported by an NHMRC Career Development Fellowship (GNT1145033)

Geospatial epidemiology of Staphylococcus aureus in a tropical setting: an enabling digital surveillance platform

Delivery of information to clinicians on evolving antimicrobial susceptibility needs to be accurate for the local needs, up-to-date and readily available at point of care. In northern Australia, bacterial infection rates are high but resistance to first- and second-line antibiotics is poorly described and currently-available datasets exclude primary healthcare data. We aimed to develop an online geospatial and interactive platform for aggregating, analysing and disseminating data on regional bacterial pathogen susceptibility. We report the epidemiology of Staphylococcus aureus as an example of the power of digital platforms to tackle the growing spread of antimicrobial resistance in a high-burden, geographically-sparse region and beyond. We developed an online geospatial platform called HOTspots that visualises antimicrobial susceptibility patterns and temporal trends. Data on clinically-important bacteria and their antibiotic susceptibility profiles were sought from retrospectively identified clinical specimens submitted to three participating pathology providers (96 unique tertiary and primary healthcare centres, n = 1,006,238 tests) between January 2008 and December 2017. Here we present data on S. aureus only. Data were available on specimen type, date and location of collection. Regions from the Australian Bureau of Statistics were used to provide spatial localisation. The online platform provides an engaging visual representation of spatial heterogeneity, demonstrating striking geographical variation in S. aureus susceptibility across northern Australia. Methicillin resistance rates vary from 46% in the west to 26% in the east. Plots generated by the platform show temporal trends in proportions of S. aureus resistant to methicillin and other antimicrobials across the three jurisdictions of northern Australia. A quarter of all, and up to 35% of methicillin-resistant S. aureus (MRSA) blood isolates in parts of the northern Australia were resistant to inducible-clindamycin. Clindamycin resistance rates in MRSA are worryingly high in regions of northern Australia and are a local impediment to empirical use of this agent for community MRSA. Visualising routinely collected laboratory data with digital platforms, allows clinicians, public health physicians and guideline developers to monitor and respond to antimicrobial resistance in a timely manner. Deployment of this platform into clinical practice supports national and global efforts to innovate traditional disease surveillance systems with the use of digital technology and to provide practical solutions to reducing the threat of antimicrobial resistance

Scabies and risk of skin sores in remote Australian Aboriginal communities: A self-controlled case series study

BACKGROUND: Skin sores caused by Group A streptococcus (GAS) infection are a major public health problem in remote Aboriginal communities. Skin sores are often associated with scabies, which is evident in scabies intervention programs where a significant reduction of skin sores is seen after focusing solely on scabies control. Our study quantifies the strength of association between skin sores and scabies among Aboriginal children from the East Arnhem region in the Northern Territory. METHODS AND RESULTS: Pre-existing datasets from three published studies, which were conducted as part of the East Arnhem Healthy Skin Project (EAHSP), were analysed. Aboriginal children were followed from birth up to 4.5 years of age. Self-controlled case series design was used to determine the risks, within individuals, of developing skin sores when infected with scabies versus when there was no scabies infection. Participants were 11.9 times more likely to develop skin sores when infected with scabies compared with times when no scabies infection was evident (Incidence Rate Ratio (IRR) 11.9; 95% CI 10.3-13.7; p1 year (IRR 0.8; 95% CI 0.7-0.9). CONCLUSION: The association between scabies and skin sores is highly significant and indicates a causal relationship. The public health importance of scabies in northern Australia is underappreciated and a concerted approach is required to recognise and eliminate scabies as an important precursor of skin sores

Estimation of the force of infection and infectious period of skin sores in remote Australian communities using interval-censored data

Prevalence of impetigo (skin sores) remains high in remote Australian Aboriginal communities, Fiji, and other areas of socio-economic disadvantage. Skin sore infections, driven primarily in these settings by Group A Streptococcus (GAS) contribute substantially to the disease burden in these areas. Despite this, estimates for the force of infection, infectious period and basic reproductive ratio—all necessary for the construction of dynamic transmission models—have not been obtained. By utilising three datasets each containing longitudinal infection information on individuals, we estimate each of these epidemiologically important parameters. With an eye to future study design, we also quantify the optimal sampling intervals for obtaining information about these parameters. We verify the estimation method through a simulation estimation study, and test each dataset to ensure suitability to the estimation method. We find that the force of infection differs by population prevalence, and the infectious period is estimated to be between 12 and 20 days. We also find that optimal sampling interval depends on setting, with an optimal sampling interval between 9 and 11 days in a high prevalence setting, and 21 and 27 days for a lower prevalence setting. These estimates unlock future model-based investigations on the transmission dynamics of skin sores

High-temperature irradiation test of UO₂ cermet fuels /

Niobium-clad niobium cermets and Type 430 stainless steel-clad molybdenum and chromium cermets, all containing 80 vol% 20% enriched UO₂, prepared by vapordeposition techniques or from the powders and densified and clad by gas-pressure bonding, were subjected to hightemperature high-heat-flux irradiation in the MTR. Two instrumerted double-walled capsules, each containing duplicate NaK-immersed cylindrical specimens of the three compositions were involved. Specimen diameters were varied according to the particular cermet thermal conductivity in an attempt to secure central temperatures of about 0.6 of the matrix melting point. Probably because of weld failures in both capsules, irradiation temperatures were higher than intended, causing loss of the chromium cermets in one capsule and all of the cermets in the other capsule. The remaining specimens were given a postirradiation dimensional and metallographic examination. The niobium-clad niobium-UO₂ cermet exhibited excellent stability at estimated center-line temperatures above 2500 deg F. A density decrease of only 1.4% was measured at a burnup of about 4 at.%. Although the capsule overheating caused the molybdenum-UO₂ cermet to partially melt, areas only a few mils from the melted zone showed no evidence of damage from the adverse conditions of the irradiation. (auth)."January 7, 1963."Includes bibliographical references (p. 20)Niobium-clad niobium cermets and Type 430 stainless steel-clad molybdenum and chromium cermets, all containing 80 vol% 20% enriched UO₂, prepared by vapordeposition techniques or from the powders and densified and clad by gas-pressure bonding, were subjected to hightemperature high-heat-flux irradiation in the MTR. Two instrumerted double-walled capsules, each containing duplicate NaK-immersed cylindrical specimens of the three compositions were involved. Specimen diameters were varied according to the particular cermet thermal conductivity in an attempt to secure central temperatures of about 0.6 of the matrix melting point. Probably because of weld failures in both capsules, irradiation temperatures were higher than intended, causing loss of the chromium cermets in one capsule and all of the cermets in the other capsule. The remaining specimens were given a postirradiation dimensional and metallographic examination. The niobium-clad niobium-UO₂ cermet exhibited excellent stability at estimated center-line temperatures above 2500 deg F. A density decrease of only 1.4% was measured at a burnup of about 4 at.%. Although the capsule overheating caused the molybdenum-UO₂ cermet to partially melt, areas only a few mils from the melted zone showed no evidence of damage from the adverse conditions of the irradiation. (auth).Work performed by the Battelle Memorial InstituteMode of access: Internet

Optimal timing of influenza vaccine during pregnancy: A systematic review and meta-analysis

BACKGROUND: Pregnant women have an elevated risk of illness and hospitalisation from influenza. Pregnant women are recommended to be prioritised for influenza vaccination during any stage of pregnancy. The risk of seasonal influenza varies substantially throughout the year in temperate climates; however, there is limited knowledge of how vaccination timing during pregnancy impacts the benefits received by the mother and foetus. OBJECTIVES: To compare antenatal vaccination timing with regard to influenza vaccine immunogenicity during pregnancy and transplacental transfer to their newborns. METHODS: Studies were eligible for inclusion if immunogenicity to influenza vaccine was evaluated in women stratified by trimester of pregnancy. Haemagglutination inhibition (HI) titres, stratified by trimester of vaccination, had to be measured at either pre-vaccination and within one month post-vaccination, post-vaccination and at delivery in the mother, or in cord/newborn blood. Authors searched PubMed, Scopus, Web of Science and EMBASE databases from inception until June 2016 and authors of identified studies were contacted for additional data. Extracted data were tabulated and summarised via random-effect meta-analyses and qualitative methods. RESULTS: Sixteen studies met the inclusion criteria. Meta-analyses found that compared with women vaccinated in an earlier trimester, those vaccinated in a later trimester had a greater fold increase in HI titres (1.33- to 1.96-fold) and higher HI titres in cord/newborn blood (1.21- to 1.64-fold). CONCLUSIONS: This review provides comparative analysis of the effect of vaccination timing on maternal immunogenicity and protection of the infant that is informative and relevant to current vaccine scheduling for pregnant women