Barbara Kachigunda

Background
The brown marmorated stink bug (Halyomorpha halys) (BSMB) is a biosecurity threat globally. Its most likely avenue of entry is via shipping transport of a multitude of commodities. Currently employed biosecurity treatments (methyl bromide, sulfuryl fluoride) pose several concerns including climate change, environmental and occupational health and safety. Ethyl formate with dilution in carbon dioxide has been shown to be an effective biosecurity treatment for controlling BMSB. Carbon dioxide is a known synergist in fumigation and is a greenhouse gas contributing to climate change.

Results
Laboratory and commercial-scale bioassays were conducted to evaluate the efficacy of ethyl formate in controlling diapausing and non-diapausing BMSB. In both trials and all treatment conditions, ethyl formate concentrations >12 mg L−1 without dilution in carbon dioxide for 3-h exposure periods were effective in achieving insect control. These results were consistent with existing literature and showed the rapid action of the fumigant in achieving a desirable level of insect mortality. The results demonstrate that even without the synergist carbon dioxide, ethyl formate can achieve complete mortality of both non-diapausing and diapausing BSMBs at a dose rate lower than the currently registered 90 mg L−1.

Conclusion
The results of this research show the commercial viability of ethyl formate, without dilution with carbon dioxide, as a biosecurity treatment for the control of BMSB, both non-diapausing and diapausing. These results will also assist in progressing the registration of the fumigant with relevant National Plant Protection Organisations. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Plant pests significantly reduce crop yield, which impacts access, availability and food utilisation. Rice is a staple crop for almost half of the world's population. Asia (including the Indo-Pacific Region, IPR) contributes 90% and consumes 86% of global rice production, but is among the most food-insecure regions in the world, with an increase of 16 million (to 113 million) moderately/severely food-insecure people in the region in the last 5 years. Outbreaks of the rice blast pathogen Pyricularia oryzae in the IPR could significantly affect global food security. Modelling indicates that an extreme case of 80% loss of rice crops across the IPR could increase global rice prices by 50-95%, increasing food insecurity for net exporter countries while creating price shocks in importing countries. This study used the four pillars of food security as a framework to evaluate the impact of rice blast on food availability, access, utilisation, and stability. The objective was to determine if biosecurity measures might be easily implemented to reduce the risk of the disease and increase food security in the region. Biosecurity was claimed as essential for managing rice blast across the pre-border/border/post-border continuum to reduce the risk to food security. Australia and New Zealand may be able to assist with the implementation of biosecurity measures as they are the most significant leaders in this field in the IPR. Regional agencies such as the Asia and Pacific Plant Protection Commission might assist the IPR in identifying threats through intelligence gathering and pathway modelling for pre-border activities. To be effective, the biosecurity system needs all stakeholders to work together.

Backgrounds

In 2022, smartphone use continues to expand with the number of smartphone subscriptions surpassing 6 billion and forecasted to grow to 7.5 billion by 2026. The necessity of these ‘high touch’ devices as essential tools in professional healthcare settings carries great risks of cross-contamination between mobile phones and hands. Current research emphasises mobile phones as fomites enhancing the risk of nosocomial disease dissemination as phone sanitisation is often overlooked. To assess and report via a large-scale E-survey the handling practices and the use of phones by healthcare workers.

Methods

A total of 377 healthcare workers (HCWs) participated in this study to fill in an E-survey online consisting of 14 questions (including categorical, ordinal, and numerical data). Analysis of categorical data used non-parametric techniques such as Pearson's chi-squared test.

Results

During an 8-h shift, 92.8% (n/N = 350/377) use their phone at work with 84.6% (n/N = 319/377) considering mobile phones as an essential tool for their job. Almost all HCWs who participated in this survey believe their mobile phones could potentially harbour microorganisms (97.1%; n/N = 366/377). Fifty-seven respondents (15.1%) indicated that they use their phones while wearing gloves and 10.3% (n/N = 39/377) have never cleaned their phones. The majority of respondents (89.3%; n/N = 337/377) agreed that contaminated mobile phones could contribute to dissemination of SARS-CoV-2.

Conclusion

Mobile phone use is now almost universal and indispensable in healthcare. Medical staff believe mobile phones can act as fomites with a potential risk for dissemination of microbes including SARS-COV-2. There is an urgent call for the incorporation of mobile phone sanitisation in infection prevention protocol. Studies on the use of ultraviolet-C based phone sanitation devices in health care settings are needed.

Introduction pathway studies generally describe the diverse routes by which non-indigenous species (NIS) can be introduced but rarely consider multiple introduction pathways occurring simultaneously. In this study, multiple pathways of NIS introduction were investigated during an industrial development on a remote island off the Australian coast. Fifteen introduction pathways were categorized in association with importing locality and the type of cargo they transported. The number and types of detection events for each introduction pathway were recorded during biosecurity inspections, cargo clearances, and surveillance conducted between 2009 and 2015. In total, more than 600,000 biosecurity inspections were completed, with 5,328 border detection events recorded constituting less than 1% of the biosecurity inspections. The border inspection events were classified as animals, plant material, soil, and organic matter, with 60% identified as dead or non-viable and 40% as alive. Of those detections, 2153 were classified as NIS, consisting of 659 identified species. Live NIS detected at the border constituted only 2% of the detections. Cargo vessel and inward-bound passenger numbers peaked during the major construction period and were associated with an increase in the number of live NIS detections. All introduction pathways have complexities, unique structural aspects, and niche areas that supported NIS in surviving the effects of treatment and evading detection during the mandatory compliance inspection. This study highlights that biosecurity incursions can be minimized if a systems approach is adopted to complement traditional and other biosecurity surveillance measures.

Introduction: Inclusion body myositis (IBM) is a progressive inflammatory myopathy characterised by skeletal muscle infiltration and myofibre invasion by CD8+ T lymphocytes. In some cases, IBM has been reported to be associated with a systemic lymphoproliferative disorder of CD8+ T cells exhibiting a highly differentiated effector phenotype known as T cell Large Granular Lymphocytic Leukemia (T-LGLL).

Methods: We investigated the incidence of a CD8+ T-LGL lymphoproliferative disorder in 85 IBM patients and an aged-matched group of 56 Healthy Controls (HC). Further, we analysed the phenotypical characteristics of the expanded T-LGLs and investigated whether their occurrence was associated with any particular HLA alleles or clinical characteristics.

Results: Blood cell analysis by flow cytometry revealed expansion of T-LGLs in 34 of the 85 (40%) IBM patients. The T cell immunophenotype of T-LGLHIGH patients was characterised by increased expression of surface molecules including CD57 and KLRG1, and to a lesser extent of CD94 and CD56 predominantly in CD8+ T cells, although we also observed modest changes in CD4+ T cells and γδ T cells. Analysis of Ki67 in CD57+ KLRG1+ T cells revealed that only a small proportion of these cells was proliferating. Comparative analysis of CD8+ and CD4+ T cells isolated from matched blood and muscle samples donated by three patients indicated a consistent pattern of more pronounced alterations in muscles, although not significant due to small sample size. In the T-LGLHIGH patient group, we found increased frequencies of perforin-producing CD8+ and CD4+ T cells that were moderately correlated to combined CD57 and KLRG1 expression. Investigation of the HLA haplotypes of 75 IBM patients identified that carriage of the HLA-C*14:02:01 allele was significantly higher in T-LGLHIGH compared to T-LGLLOW individuals. Expansion of T-LGL was not significantly associated with seropositivity patient status for anti-cytosolic 5'-nucleotidase 1A autoantibodies. Clinically, the age at disease onset and disease duration were similar in the T-LGLHIGH and T-LGLLOW patient groups. However, metadata analysis of functional alterations indicated that patients with expanded T-LGL more frequently relied on mobility aids than T-LGLLOW patients indicating greater disease severity.

Conclusion: Altogether, these results suggest that T-LGL expansion occurring in IBM patients is correlated with exacerbated immune dysregulation and increased disease burden.

Appropriate inspection protocols and mitigation strategies are a critical component of effective biosecurity measures, enabling implementation of sound management decisions. Statistical models to analyze biosecurity surveillance data are integral to this decision-making process. Our research focuses on analyzing border interception biosecurity data collected from a Class A Nature Reserve, Barrow Island, in Western Australia and the associated covariates describing both spatial and temporal interception patterns. A clustering analysis approach was adopted using a generalization of the popular k-means algorithm appropriate for mixed-type data. The analysis approach compared the efficiency of clustering using only the numerical data, then subsequently including covariates to the clustering. Based on numerical data only, three clusters gave an acceptable fit and provided information about the underlying data characteristics. Incorporation of covariates into the model suggested four distinct clusters dominated by physical location and type of detection. Clustering increases interpretability of complex models and is useful in data mining to highlight patterns to describe underlying processes in biosecurity and other research areas. Availability of more relevant data would greatly improve the model. Based on outcomes from our research we recommend broader use of cluster models in biosecurity data, with testing of these models on more datasets to validate the model choice and identify important explanatory variables.

Biosecurity in Australia and globally is based on understanding and protection of our national health, economy, industries, and environment from the negative effects associated with invasive pests and pathogens. The biosecurity continuum includes pre-border preparedness, border protection and post-border management, eradication, and control. The biosecurity system in Australia aims to manage risks and reduce the likelihood and adverse consequences of pest and disease incursions on human, animal and plant health, the environment, and the economy.

To identify biosecurity risks and solve pertinent issues in biosecurity, analysts must gather and collate information for multiple factors and from a variety of sources in areas including agriculture, the environment and public health. The amount and complexity of biosecurity data have exposed the limitations in traditional statistical methodologies in addressing issues in biosecurity management. Biosecurity surveillance data is challenging in terms of non-normality, over-dispersion and typically zero-inflated. This type of data follows a natural process rather than a pre-specified process or distribution models, and often contains a large proportion of zeros. Application of appropriate statistical models to analyse these unique data sets is essential to effective biosecurity decision-making. The data used throughout this thesis were typically characteristic of biosecurity data, containing a large proportion of zeros, non-normality, and over-dispersion. Data used were collected as part of a biosecurity program implemented on Barrow Island, a remote island off the western Australian coastline, prior to and during the development of an industrial project on the island.

In the following research, the first step encompassed evaluation of a range of candidate statistical models for describing biosecurity border and post-border detection of terrestrial non-indigenous species.

The dataset was fitted with a variety of models including lognormal linear model, Poisson and negative binomial generalized linear models, zero-inflated model, a three-component mixture mode and a clustering analysis approach. A clustering analysis approach was adopted using a generalization of the popular k-means algorithm appropriate for mixed-type data. The analysis approach involved determination of the most appropriate number of clusters using just the numerical data, then subsequently including covariates to the clustering. Based on the counts alone, three clusters gave an acceptable fit and provided information about the underlying data characteristics. Incorporation of covariates into the model suggested four distinct clusters dominated by physical location and type of detection. Though the three-component log-normal mixture model provided detailed insight into the distribution of the data by dividing the data according to their distinct characteristic of numerical ordering, the clustering model was the preferred approach for this study. Availability of more relevant data would greatly improve the model. Broader use of cluster models in biosecurity data is recommended, with testing of these models on more datasets to validate the model choice and identify important explanatory variables.

Investigation of the diverse routes by which non-indigenous species can be introduced is also of key importance to biosecurity. A gap in many introductory pathway studies is the limited consideration given to multiple introduction pathways occurring simultaneously. Multiple pathways of non-indigenous species introduction to Barrow Island were investigated and fifteen potential modes of introduction were identified in association with importing location and personnel required for the project. Three-way management prioritisation using boosted regression modelling to determine the most important factors influencing the detection of non-indigenous species at the biosecurity border was assessed. Factors considered in detecting non-indigenous species included potential modes of introduction, detection type, border inspection point (physical location on Barrow Island), phase of industrial development, year, and month of detection, of which detection type, border inspection point and potential modes of introductions were key factors.

Cargo vessel and inward bound passenger numbers peaked during the construction period and were associated with an increase in the number of live non-indigenous species detections. Exposed potential modes of introductions (e.g. flat racks and vessel topsides) contained a more diverse species assemblage, while potential modes of introductions associated with human habitation and activity had the highest likelihood of introducing live non-indigenous species. The nature of these potential modes of introductions potentially allowed non-indigenous species habitation of niche areas and/or provided a suitable food supply. Invertebrates comprised 73% of the detections, with 43% live non-indigenous species. Structures such as landings and jetties were recorded as invasion hotspots, consistent with being the first point of entry for arriving vessels. Human-inhabited environments reported abundant commensal non-indigenous species.

Our study indicates that biosecurity surveillance programs need to prioritise management of specific species, potential modes of introductions, and sensitive and susceptible sites to target potential invasions. Biosecurity managers should prioritise potential modes of introductions with the highest likelihood of live non-indigenous species detection based on specific potential modes of introductions characteristics, including niche availability and habitat suitability.

The study provided insight into how biosecurity surveillance programs need to assess current data and adapt management strategies appropriately. Evaluation of the predictive performance of models used in biosecurity surveillance is integral to subsequent management decision-making. This includes assessing the suitability of the model for specific applications, i.e. identifying important potential predictors, undertaking a comparative assessment of competing models and modelling techniques, and identifying aspects of the model that might need improvement.

Opportunities to use statistical science for biosurveillance are vast, as are the challenges associated with available data related to biosecurity. This thesis explored a variety of analytical statistical methods to enhance interpretation and decision making in biosecurity, while also acknowledging the challenges associated with this type of data. There is a growing need to leverage scientific models and predictive analytics to improve decision making in the context of biosecurity management.

Farmers in Northern Communal Areas (NCA) of Namibia practise conventional tillage using mouldboard or disc implements that pulverise fragile soil structures thereby destroying vital organic matter. This subsequently creates hard pans and plough lines that lead to soil degradation and consequently reduced moisture content and low yields leading to food insecurity. Studies were conducted at the Ogongo Campus of the University of Namibia between 2011 and 2013 to compare the differences between two conventional tillage (CV) treatments (i.e. tractor - drawn disc harrow (TDH) and animal - drawn mouldboard plough (AMP) and two Namibia Specific Conservation tillage (NSCT) treatments (tractor - drawn ripper furrower (TRF) and animal - drawn ripper furrowers (ARF) used by farmers in Namibia. A Fallow treatment of No tillage No crop (NTNC) was used as a control. The experimental research design used was a „split plot randomized complete block design‟ with tillage method as the main plot factor, and two mulch rates (0 and 3 t ha-1) as the subplot factor in 4 blocks, totalling 40 plots. This study showed significant (p<0.003) differences in moisture among tillage methods and interaction between time and tillage (p<0.001), with soil moisture peaks in February for both years. TRF resulted in the highest percentage increase in moisture content with 8.1%, whilst TDH increased by 3.9%, ARF increased by 3.1%, AMP actually decreased by 3.1% over the two year period. There was however no mulch effect on the moisture levels over the two years. Overall, the moisture contents under the NSCT treatments were higher than the corresponding moisture contents under the CV technologies and fallow treatments, Farmers in the NCA of Namibia are therefore advised to adopt the NSCT methods.

Studies were conducted at the Ogongo Campus of University of Namibia between 2011 and 2012 to compare the differences between two conventional tillage (CV) treatments (i.e. tractor - drawn disc harrow (TDH) and animal - drawn mouldboard plough (AMP) and two NSCT treatments (tractor - drawn ripper furrower (TRF) and animal - drawn ripper furrowers (ARF) used by farmers in the Northern Communal Areas (NCA) of Namibia. This paper is the first volume of a series of papers to report on the comparisons of the two technologies on field performances of tillage methods and their effects on moisture, compaction, roots and yield. For this paper, the parameters evaluated were root length and yield. The research design was a split plot design with tillage as main plot treatment whilst mulch was the sub plot treatment. Yields were not significantly influenced by tillage (p = 0.410 in 2011 and 0.078 in 2012) but root length were significantly influenced by tillage in the second year (p<0.005). There were no significant differences in mulched plots vs unmulched plots among the tillage methods. Both NSCT methods (TRF with mulch and ARF with mulch) achieved longer root lengths than CV methods (TDH and AMP) by 24.5% and 8.5% respectively. Tractor ripper furrower (TRF) achieved the longest mean roots and yields in 2012. The NSCT methods (TRF and ARF) achieved higher yields than CV methods (TDH and AMP) by 10.1% and 11% respectively. The results also suggests that farm yields can be increased from an average of 400 kg ha-1 through better management that includes use of CT implements, manure, fertilizer and mulch.