Output list
Journal article
Published 2025
Pest management science, Early View
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.
Journal article
Published 2025
NeoBiota, 100, 371 - 400
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.
Journal article
Published 2023
Infection, Disease & Health, 28, 1, 19 - 26
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.
Journal article
Published 2023
Biological invasions
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.
Journal article
Published 2023
Frontiers in immunology, 14, Art. 1153789
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.
Journal article
Published 2022
PLoS ONE, 17, 8, Art. e0272413
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.
Journal article
Published 2019
International Journal of Recent Engineering Research and Development, 4, 2, 48 - 55
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.
Journal article
Published 2018
American Academic Scientific Research Journal for Engineering, Technology, and Sciences, 40, 1, 27 - 39
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.
Journal article
Published 2014
International science and technology journal of Namibia, 4, 7 - 22
The International Centre for Research in Agroforestry (ICRAF now known as the World Agroforestry Centre) initiated research and development work on at least 20 priority indigenous fruit trees in 5 countries in Southern Africa including Zimbabwe. The long term objective of this work was to improve food security and income generating capacities of local communities through domestication, marketing and commercialisation of indigenous fruit trees. Country specific priority species were identified based on consultations with a wide range of users. For Zimbabwe, Uapaca kirkiana emerged as a priority species with economic potential and has since become the focus of intensive research. A study aimed at identifying and selecting superior phenotypes of U. Dhliwayo-Chiunzi et al. /ISTJN 2014, 4:7-22. Phenotypes Of U. Kirkiana Muell Arg. phenotypes. Tree location and altitude were recorded using the Geographical Positioning System (GPS). Fruit size, colour, shape were recorded. Total Soluble Solutes (TSS %) was measured using a hand refractometer. The largest fruits (42.3 g/fruit) were collected from Gokwe (ICR03GokZW41) whilst the smallest fruits (9.1 g/fruit) were collected from Rusape (ICR03RusZW53). Fresh fruit weight was strongly correlated to the seed weight (r = 0.813). Fruits with higher pulp content had a lower seed weight (r = −0.452). Fruits from Gokwe and Masvingo had higher TSS percentage. Basing on stakeholders' selection criteria and laboratory analysis, 23 trees above the mean fruit weight (20.63 g/fruit) were classified as large, whilst 24 trees with pulp content above the mean of 45.18% were classed as pulpy and 22 trees with TSS above 19.53% were classed as sweet. Similarity of the phenotypes was determined through complete linkage in hierarchical cluster analysis. Clustering confirmed the characterisation by farmers using taste as a key method of selecting suitable phenotypes. In-situ conservation and establishment of clones from the selected trees is recommended for purposes of com-mercialising these superior phenotypes.
Journal article
Published First Quarter 2010
Water SA, 36, 36 3, 215 - 220
Marine fish-processing plants often use seawater during their operations. Chlorination and UV are commonly used for dis-infection of this water but may not be effective in preventing biofilm formation within the water distribution network. These biofilms negatively impact water quality and could lead to contamination of fish products. During a recent study, Vibrio alginolyticus strains were detected on processed hake. The presence of most Vibrio spp. on fish products is of consumer safety concern and needs to be minimised. Water treatment strategies effective for seawater disinfection but with minimal negative effect on fish quality are required. In this study the effectiveness of chlorine, ozone and hydrogen peroxide (H 2 O 2) in the inhibition of mature biofilms or biofilm formation in natural seawater was investigated. Two V. alginolyticus strains (V590 and V595) isolated from hake fish as well as the type strains of V. alginolyticus LMG 4409 and V. parahaemolyticus LMG 2850 were used. Chlorine was ineffective as experiments showed that strains V590, V595 and V. parahaemolyticus LMG 2850 could form biofilms even in the presence of 4 mg/ℓ of chlorine. When ozone was used, biofilm initiation and formation were completely inhibited for only 2 strains of V. alginoluticus, i.e. LMG 4409 and V590, at 1.6 mg/ℓ or 0.8 mg/ℓ ozone, respectively. Hydrogen peroxide performed the best of all the disinfectants evaluated in this study. Inhibition of biofilm formation was observed for all strains at 0.05% H 2 O 2. The mature biofilms were more resistant to H 2 O 2 but were all eliminated at 0.2% concentrations. This study indicated that H 2 O 2 is the most effective biocide to prevent biofilm formation in seawater distribution networks and could potentially be used as an alternative or supplementary disinfectant of seawater in marine fish-processing plants.