Research Articles (University of Pretoria)

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This collection offers open access to the full text of research articles published by staff, students and affiliates of the University of Pretoria. These items are identical in content to their published counterparts. It is linked to the Research Information System and complements the Annual Research Report.

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Neonatal encephalopathy due to suspected hypoxic-ischaemic encephalopathy
(Springer, 2025) Horn, Alan Richard; Pillay, Shakti; Velaphi, Sithembiso Christopher; Ballot, Daynia Elizabeth; Mellet, Juanitah; Foden, Caroline; Van Rensburg, Jeanne; Babbo, Carina Corte-Real; Kali, Gugulabatembunahlubi Tenjiwe Jabulile; Coetzee, Melantha; Masemola, Mogomane Yvonne Khomotso; Nakwa, Firdose Lambey; Pepper, Michael Sean; michael.pepper@up.ac.za
No abstract available.
Determining sound exposure levels for marine fauna during a past seismic survey to inform effective mitigation measures in South African waters
(Elsevier, 2025-11) Purdon, Jean; Shabangu, Fannie Welcome; Pienaar, Marc; Findlay, Kenneth Pierce; Somers, Michael J.; Vermeulen, Els; Scheun, Juan; Doh, Yann
Please read abstract in the article.
Estimated baseline density of a spotted hyaena population in a post-war landscape
(Cambridge University Press, 2025) Briers-Louw, Willem D.; Kendon, Tamar A.; Rogan, Matthew S.; Leslie, Alison J.; Bantlin, Drew; Evers, Emma; Gaynor, David; Lindsey, Peter; Almeida, Joao; Naude, Vincent N.
The spotted hyaena Crocuta crocuta is relatively understudied across its range despite evidence of widespread declines. It is therefore essential that robust baseline population density assessments are conducted to inform current management and future conservation policy. In Mozambique this is urgent as decades of armed conflict followed by unchecked poaching have resulted in large-scale wildlife declines and extirpations. We conducted the first robust population density estimate for a spotted hyaena population in Mozambique using spatially explicit capture–recapture methodologies. We recorded a relatively low population density of 0.8–2.1 hyaenas/100 km2 in the wildlife management area Coutada 11 in the Zambezi Delta of central Mozambique in 2021. These densities are well below the estimated carrying capacity for the landscape and are comparable to published densities in high human-impact, miombo woodland-dominated and arid environments. The combination of historical armed conflict, marginal trophy hunting and bushmeat poaching using wire snares and gin traps (with physical injuries evident in 9% of identified individuals) presents persistent anthropogenic pressure, limiting the post-war recovery of this resident hyaena population. We provide insights into the dynamics of hyaena population status and recovery in such post-war landscapes, adding to mounting evidence that the species is less resilient to severe anthropogenic disturbances than previously believed. We recommend long-term monitoring of this and other carnivore populations in post-war landscapes to ascertain demographic trends and implement effective conservation interventions for population recovery.
Camera trap-based estimates reveal spatial variability in African clawless otter population densities and behaviour
(Cambridge University Press, 2025) Lewis, Candice B.; Majelantle, Tshepiso Lesedi; Haussmann, Natalie S.; Mcintyre, Trevor
Estimating the population size of shy and elusive species is challenging but necessary to inform appropriate conservation actions for threatened or declining species. Using camera-trap surveys conducted during 2017–2021, we estimated and compared African clawless otter Aonyx capensis population densities and activity times in six conserved areas in southern Africa. We used two different models to estimate densities: random encounter models and camera-trap distance sampling. Our results highlight a general pattern of higher estimated densities and narrower confidence intervals using random encounter models compared to camera-trap distance sampling. We found substantial variation in densities between study areas, with random encounter model estimates ranging between 0.9 and 4.2 otters/km2. Our camera-trap distance sampling estimates supported the relative density estimates obtained from random encounter models but were generally lower and more variable, ranging from 0.8 to 4.0 otters/km2. We found significant differences in otter activity patterns, with populations either being nocturnal, mostly nocturnal or cathemeral. As all study areas experience little human disturbance, our results suggest that there are large natural variations in otter densities and activity patterns between regions. When densities are converted to metrics that are comparable to previous studies, our estimates suggest that African clawless otter population numbers are generally lower than previously reported. This highlights a need for broader spatial coverage of otter population assessments and future studies to assess potential environmental drivers of spatial, and potentially temporal, variation in population numbers and activity patterns.
A retrospective radiologic analysis of the treatment outcomes of ameloblastomas
(Wiley, 2025-05) Smit, Chane; Robinson, Liam; Fonseca, Felipe Paiva; Van Heerden, Willem Francois Petrus; Uys, Andre; chane.smit@up.ac.za
INTRODUCTION : The current study reviewed the postoperative radiologic findings of 156 cases of ameloblastoma diagnosed at a tertiary institution in South Africa. METHODS : Histologically diagnosed cases of ameloblastomas between 2012 and 2022 were retrospectively reviewed. Only cases with both pre- and postoperative radiographs of diagnostic quality were included in the study. The demographics, treatment and follow-up radiologic findings, including recurrences, were assessed. This clinical data was collected from all available patient records and histopathologic reports. RESULTS : Seventy-nine cases of ameloblastoma (50.97%) diagnosed at the institution had post-treatment radiographs available and were included in the study for further analysis. Conservative treatment, including marsupialisation and/or enucleation, was performed in 11 cases (13.92%). The recurrence rate for conservatively treated cases was 44.4% after a mean follow-up of 31.4 months. Tumour resection was performed in 72 cases (91.1%), including 4 recurrent cases previously treated conservatively. Tumour recurrence was only noted in 4 cases (7.5%) treated via surgical resection after a mean follow-up of 25 months. Spontaneous bone regeneration was seen in 19 cases (35.8%) of ameloblastomas treated via surgical resection. CONCLUSION : Ameloblastomas are benign neoplasms with high recurrence rates, emphasising the need for appropriate treatment and extended follow-up periods. The high recurrence rate reported in cases of ameloblastoma managed conservatively highlighted its inappropriate use in treating conventional subtypes. The presence of bony regeneration in this study was higher than the reported literature, correlating with the overall younger age of the current sample.
A minimax approach to duality for linear distributional sensitivity testing
(Taylor and Francis, 2025) Van Zyl, Gusti; gusti.vanzyl@up.ac.za
We consider the dual formulation of the problem of finding the maximum of 𝔼𝜈⁡[𝑓⁡(𝑋)], where ν is allowed to vary over all the probability measures on a Polish space 𝒳 for which 𝑑𝑐⁡(𝜇,𝜈)≤𝑟, with 𝑑𝑐 an optimal transport distance, f a real-valued function on 𝒳 satisfying some regularity, μ a ‘baseline’ measure and 𝑟≥ 0. Whereas some derivations of the dual rely on Fenchel duality, applied on a vector space of functions in duality with a vector space of measures, we impose compactness on 𝒳 to allow the use of the minimax theorem of Ky Fan, which does not require vector space structure.
Turbomachinery blade behaviour analysis using a photogrammetric stereovision 3D based shape analysis approach
(Elsevier, 2025-03) Gwashavanhu, Benjamin Katerere; Oberholster, Abraham Johannes (Abrie); Heyns, P.S. (Philippus Stephanus); abrie.oberholster@up.ac.za
Vibrational data analysis is a widely popular tool employed for condition monitoring and asset integrity analysis of rotating machinery. Due to the intrusive nature of conventional contact transducers such as accelerometers, noncontact photogrammetric techniques such as 3D point tracking (3DPT) and digital image correlation (DIC) are considered viable alternatives for certain applications. These techniques have been successfully used to capture operational vibration data of turbomachines such as wind turbines. These techniques, however, typically require prior surface preparation by way of either attaching distinct traceable markers or spray painting of the specimen. Prior surface preparation not only necessitates costly machine shutdowns, but can also be very complex to implement. This paper presents a novel approach focusing on 3D shape variation analysis without the requirement for prior surface preparation. The analysis is performed on blade profile contours extracted from images of rotating blades. This novel approach incorporates statistical shape descriptor analysis on rotating blades to capture dynamics, identifying damage, and perform damage severity classification of the blades. The definition of principal component based geometric modes for a 3D shape is presented, and the relationship between these modes and the outline of a shape of interest successfully investigated. Shape Principal Component Descriptors (SPCDs) that can be analysed to characterize the dynamic properties of a machine are proposed. In conjunction with a Finite Element (FE) numerical model of a physical rotor, it is shown that these uniquely defined descriptors can be used to capture differences in the dynamic behaviour of rotor blades. A clustering technique is employed to classify individual damaged blades, and results from investigations to better understand descriptor sensitivity to vibration amplitude and shape orientation transformation are presented. Results from an experimental study of the physical rotor utilizing a stereoscopic camera setup are also presented. Results from principal component analysis (PCA) of the SPCDs further demonstrate the feasibility of this shape-based measurement technique for online condition monitoring of rotating turbomachines. HIGHLIGHTS • Application of a 3D shape-based photogrammetric technique for condition monitoring. • Introduction of PCA-based geometric modes for boundary shape variation analysis. • Online turbomachinery blade analysis using a statistical approach. • Blade damage detection and classification through clustering of shape features.
African Initiated Churches and ecological sustainability : an empirical exploration
(De Gruyter, 2025-05) Stork, Juliane; Öhlmann, Philipp
While African Initiated Churches are increasingly recognized as actors of social development, little research has thus far elucidated their role regarding ecological sustainability. Responding to this gap, we explore African Initiated Churches’ views on ecological sustainability and their reaction to environmental destruction and climate change. We analyse to what extent environmental concerns are considered relevant, explore emerging environmental concepts and theologies, and highlight environmental actions taken. The analysis is based on a diverse set of qualitative and quantitative data focusing on leaders of African Initiated Churches from across Sub-Saharan Africa: interviews and focus groups, public lectures, and online survey data. The findings show an ecological turn in African Initiated Christianity. Unlike in mainline Christianity, where ecological engagement is often embedded in elaborated eco-theologies, African Initiated Churches’ engagement with ecological sustainability seems to be primarily driven by the increasing adverse effects of environmental degradation and climate change in their communities.
The epidemiology and pattern of orthopaedic injuries caused by delivery motorbike accidents (DMBA) at a South African tertiary hospital
(Bentham Open, 2025-03) Nzimande, Sibusiso M.D.; Sukati, Falethu M.
BACKGROUND : The orthopaedic department at Steve Biko Academic Hospital (SBAH) has observed an increasing number of patients presenting with serious orthopaedic injuries due to Delivery Motorbike Accidents (DMBA). These patients sustain severe injuries that require major surgical procedures. OBJECTIVE : The aim of this study was to determine the pattern and severity of orthopaedic injuries due to delivery motorbike accidents (DMBA). METHODS : This was a retrospective qualitative observational study between 1st January, 2020, and 31st December, 2022. The details of patients involved in motorbike accidents (MBA) were collected from patient registers at the emergency department and used to obtain clinical data from medical and radiological records in the form of patient files and patient archiving and communication system (PACS), respectively. RESULTS : A total of 227 patients presented to the emergency department with orthopaedic injuries following a motorbike accident over a period of 3 years. Ninety-seven (97) files could not be retrieved from the patient records department. Sixty-seven (67) patients had their occupation recorded as unknown or unemployed. Sixty (60) patients had their occupation indicated in the file by the clinicians or administration clerks. Twenty-nine patients (48%) had their occupation indicated as delivery men or employees of a delivery company. All patients were males, presented after hours, and sustained multiple injuries that required surgical management. Four patients had their helmet usage status recorded in the file. CONCLUSION : The study addresses a significant and underexplored issue in public health and occupational safety, providing preliminary insights into the patterns and severity of orthopaedic injuries caused by delivery motorbike accidents at Steve Biko Academic Hospital. Future research should adopt a prospective design to ensure more comprehensive data collection and explore the broader social and policy implications of delivery motorbike accidents.
Knowledge, attitudes and practices of men and women regarding infertility in the City of Tshwane, Pretoria, South Africa
(Bentham Open, 2025-07) Mabitsela, Vangile Naney; Masenge, Andries; Musie, Maurine Rofhiwa; Sepeng, Nombulelo Veronica
INTRODUCTION : Infertility continues to be a major public health issue with deep social and psychological effects, particularly in low- and middle-income environments. The purpose of this study was to evaluate the knowledge, attitudes, and practices of men and women around infertility in the City of Tshwane, Pretoria, South Africa. METHODS : This descriptive quantitative study surveyed 390 participants in Tshwane District primary healthcare settings using a self-administered questionnaire and stratified sampling. RESULTS : The study found that most participants had a good understanding of infertility causes, with 67.4% identifying menstrual cycle irregularities as a potential factor for female infertility and 64.4% recognizing semen abnormalities as a cause for male infertility. However, there were some misconceptions identified, such as 30.5% of people believed that infertility was more common in women than in men, and 69.2% of individuals considered it a disability. With 79.5% of respondents identifying infertility as a medical problem, attitudes regarding it were largely positive. The majority—90.7% of the participants—were open to changes in lifestyle and assisted reproductive methods, such as IVF. Gender differences in coping mechanisms were found in that 79.2% of males favoured traditional medicine for the treatment of infertility, while 90% of the women preferred spiritual or religious practices. DISCUSSION : According to this study, both men and women in Tshwane had favourable views and good knowledge regarding infertility. Though there were some misunderstandings, most participants were aware of some causes of infertility. Openness to medical treatments was noted in the willingness to embrace assisted reproduction and lifestyle modifications. CONCLUSION : The study found that while men and women had knowledge and positive attitudes toward infertility. However, misconceptions, such as viewing infertility as a disability and as a woman’s problem, persisted. Attitudes towards infertility from both genders were mainly positive, with significant support for lifestyle modifications and assisted reproduction technology. Gender differences in coping mechanisms were evident, with males choosing traditional medicine while women favoured religious methods. To increase awareness and lessen the stigma associated with infertility, the study stressed the need for gender-sensitive, culturally relevant health educational initiatives to improve awareness and address misconceptions.
Cameroon’s bicultural conundrum : the anglophone ‘special status’ oxymoron
(Scandinavian University Press, 2025-06) Fombad, Charles Manga; charles.fombad@up.ac.za
The ongoing crisis in Cameroon offers a painful example of the consequences of mismanaging bicultural diversity through poor constitutional design. The 1961 Federal Constitution that paved the way for the union of the minority anglophones and majority francophones was dismantled and replaced with a highly centralised unitary system in which the distinctive features of the anglophone communities’ cultural and institutional identity were progressively removed under the pretext of national unity. Anglophone protests over the years against discrimination were ignored until this degenerated into a civil war that started in 2016. In 2019, the government finally yielded to internal and external pressure and enacted a General Code which purports to give a special status to the two restive anglophone regions. This paper seeks to assess whether this Code responds to the opportunities and challenges posed by Cameroon’s bicultural diversity conundrum in a manner that promotes democracy, social justice, sustainable peace, and stability. The analysis is situated within the context of the theoretical debates between integrationist and accommodationist approaches to managing cultural pluralism. The paper argues that only a profound constitutional change can pave the way for sustainable peace and stability. This Cameroonian experiment offers lessons to many countries today grappling with similar challenges.
The impact of IT ambidexterity on organizational agility : the mediating role of organizational change capacity
(Association for Information Systems, 2025-03) Rawat, Waseem; Barnes, Justin
BACKGROUND : Organizational agility (OA) is recognized as a vital capability for competitiveness in dynamic business environments. While IT capabilities are acknowledged as a potential source of OA, there is limited research on the agility-enabling role of IT ambidexterity (ITA), which is the dual pursuit of IT exploitation and IT exploration. In particular, the influence of ITA on market capitalizing agility (MCA) and operational adjustment agility (OAA), which are key agility dimensions, remains unexplored. Although prior work has argued that intermediary organizational capabilities may be required to translate IT capabilities into OA, no previous studies have considered the role of organizational change capacity (OCC), in the ITA-OA relationship. To address these gaps, we draw on the dynamic capability view and the IT-enabled agility literature to examine the relationships between ITA and MCA, OAA, and OA, and propose that OCC mediates these relationships. METHOD : A comprehensive quantitative approach, involving the development of a robust research instrument, was used to empirically investigate the relationships between the constructs. Survey data was collected from 173 IT professionals. The analysis was performed using partial least squares structural equation modelling to assess the measurement model and to test the hypotheses. RESULTS : Our findings reveal that ITA has a direct positive impact on MCA, OAA, and OA, while OCC partially mediates the ITA-MCA, ITA-OAA, and ITA-OA relationships. All measurement and structural model assessment criteria were met, demonstrating the robustness of our conceptualized model. CONCLUSION : The results highlight the importance of balancing IT exploitation and exploration to foster OA, particularly through OAA and MCA, and introduces OCC as an intermediary capability that facilitates the translation of ITA into OA, and its dimensions. The theoretical arguments and empirical evidence offer insights for future research and organizational practice into the direct and indirect role of ITA in developing organizational dynamic capabilities.
Solving climate change requires changing our food systems
(Oxford University Press, 2025-01) Feigin, Svetlana V.; Wiebers, David O.; Blumstein, Daniel T.; Knight, Andrew; Eshel, Gidon; Lueddeke, George; Kopnina, Helen; Feigin, Valery L.; Morand, Serge; Lee, Kelley; Brainin, Michael; Shackelford, Todd K.; Alexander, Shelley M.; Marcum, James; Merskin, Debra; Skerratt, Lee F.; Van Kleef, Gerben A.; Whitfort, Amanda; Freeman, Carrie P.; Winkler, Andrea Sylvia
Humanity is facing an important existential threat—irreversible climate change caused by human activity. Until recently, most of the proposals to address climate change have downplayed or ignored the adverse impact of food systems, especially intensive animal agriculture. This is in spite of the fact that up to a third of global greenhouse gas production to date can be attributed to animal agriculture. Recent developments at COP28 have signaled that the tide is turning, however, and that food systems are becoming part of global discussions on climate change solutions. The pressing nature of irreversible climate change requires rethinking our food systems. To solve the climate change crisis, we propose transitioning to a predominantly plant-based diet, and phasing out intensive animal agriculture as diets shift, without increasing pastoral farming. We suggest that such transformations in global food systems can be accomplished largely through education and large-scale public information campaigns, removal of subsidies, taxation to account for externalized costs of animal agriculture, improved labelling of products, and various investment/divestment drivers. Better metrics and industry benchmarks involving food and agriculture-specific performance indicators that reflect food system sustainability will be important. Increased global awareness of these issues and a change in mindset (which will drive political will) also are needed. Our current trajectory is untenable, and we must begin to turn the ship now towards sustainable food systems and diets.
Prioritising intervention areas for antimicrobial resistance in Nigeria's human and animal health sectors using a mixed-methods approach
(Elsevier, 2025-06) Awulu, Oche A.; Jenkins, Akinbowale; Balogun, Babatunde A.; Chukwu, Emelda E.; Fasina, Folorunso Oludayo; Egwuenu, Abiodun; Oduyebo, Oyinlola O.; Bamidele, Tajudeen A.; Cadmus, Simeon; Aworh, Mabel K.; Adekola, Adewole A.; Desbois, Andrew P.; Chah, Kennedy F.; Brunton, Lucy A.
A One Health approach is essential to prioritise intervention areas to tackle antimicrobial resistance (AMR). This study aimed to identify and evaluate critical drivers and antimicrobial stewardship (AMS) challenges within Nigeria's human and animal health sectors. Human (22) and animal (33) health professionals in Nigeria were asked via an online questionnaire to rank priority pathogens, AMS challenges, and AMR drivers identified by subject matter experts. Descriptive statistics and the Fisher's exact test were used to evaluate differences in rankings between sectors. Subsequently, a scoping literature review of peer-reviewed research and grey literature was conducted to evaluate the evidence supporting the rankings. Salmonella spp. (28.5 %) and Escherichia coli (28.2 %) were selected as the top-ranked priority pathogens for AMR. The Fisher's exact test showed a significant association (p = 0.049) between profession and ranking of Salmonella, which was ranked higher by animal health professionals than their human health counterparts. Priority AMS challenges in both human and animal health sectors were “ease of access to over-the-counter antimicrobials” (14.9 % and 20.1 %, respectively) and “lack of awareness of AMR/AMS” (14.1 % and 20.4 %, respectively). “Lack of infection prevention and control (IPC)” (24.5 %) was the highest-ranked AMR driver across sectors. Differences were observed between the rankings human and animal health professionals gave to the challenge of access to veterinary expertise (p = 0.011), as medical doctors ranked this component higher than veterinarians. “Lack of IPC” (p = 0.022) and “environmental degradation” (p = 0.048) were ranked higher by medical doctors than veterinarians. Conversely, “unsanitary processes in the abattoir(s)” was ranked higher among veterinarians (p = 0.032). Of the 84 articles reviewed, 62 supported the rankings of AMS challenges in both sectors, while 24 captured relevant AMR drivers. Our findings underscore the need for a One Health approach in Nigeria to improve AMS and curb AMR.
Mpox : a case study for a one health approach to infectious disease prevention
(Elsevier, 2025-06) Hayman, David T.S.; Koopmans, Marion P.G.; Cunningham, Andrew A.; Bukachi, Salome A.; Masirika, Leandre Murhula; Markotter, Wanda; Mettenleiter, Thomas C.; wanda.markotter@up.ac.za
Mpox has been declared a global health emergency twice by the World Health Organization due to its impacts within and beyond Africa. Enzootic in Central and West African wildlife, mpox outbreaks have resulted from zoonotic spillover, with recent events revealing increased human-to-human transmission. Factors like population growth and environmental disruption, alongside reduced smallpox immunity, increase emergence risk. In addition, the emergence in South Kivu of a distinct subclade of mpox virus points at a currently understudied aspect of mpox virus lineages and their dynamics in reservoir hosts. A One Health approach—integrating human, animal, and environmental science—is essential for reducing the risk of mpox emergence. This approach should encompass ecological studies to understand putative reservoir population dynamics and the potential for interventions, reducing activities that increase human-animal contacts, respectful community engagement to reduce spillover risk from cultural practices (such as hunting multiple species of wildlife for consumption), and socially acceptable and equitable access to medical and non-medical countermeasures to prevent or control ongoing human-to-human transmission. Politically supported collaborative efforts across disciplines with involvement of stakeholders are critical to promote and strengthen socially and environmentally sustainable practices to mitigate future outbreaks. HIGHLIGHTS • Human-human spread and zoonotic spillover of mpox outbreaks is worsened by population growth, habitat change and low immunity • A distinct mpox virus subclade in South Kivu, DRC, highlights the need for further research on virus lineages and reservoir host dynamics. • A One Health approach is key to prevention, using ecology, engagement, and equitable access to interventions.
Enhancing global health security in Sub-Saharan Africa : the case for integrated One Health surveillance against zoonotic diseases and environmental threats
(Elsevier, 2025-12) Gashema, Pierre; Sesonga, Placide; Iradukunda, Patrick Gad; Muvunyi, Richard; Mugisha, Jean Claude; Ndayisenga, Jerome; Musafiri, Tumusime; Habimana, Richard; Bigirimana, Radjabu; Kabanda, Alice; Gashegu, Misbah; Gahamanyi, Noel; Izudi, Jonathan; Siddig, Emmanuel Edwar; Ngabonziza, Jean Claude Semuto; Ahmed, Ayman; Dzinamarira, Tafadzwa; Mutesa, Leon; Muvuny, Claude Mambo
Integrated One Health surveillance is pivotal to Africa's future health security, particularly in preventing and managing zoonotic and environmental health threats. The One Health strategy recognizes the interconnectedness of human, animal, and environmental health, allowing a holistic framework for tracking and responding to emerging and re-emerging pathogens. The One Health approach facilitates cross-sectoral data sharing and enhances surveillance, enabling the early detection and response to potential outbreaks. This proactive approach shifts the paradigm from reactive crisis management to preventive containment strategies. However, challenges such as funding gaps, limited infrastructure, limited diagnostic capacity, and weak multi-sectoral and cross-border collaborations remain. This perspective paper aims to 1) explore the effectiveness of integrated One Health surveillance in early detection and response to zoonotic diseases and environmental threats in Sub-Saharan Africa (SSA), and 2) identify key challenges and proposed solutions to strengthen regional health security. A multisectoral laboratory working group (MLWG) emerged as a pillar to enable active surveillance targeting humans, animals, and the environment. This paper highlighted essential strategies for enhancing One Health surveillance in SSA in light of the recent Marburg virus disease in Rwanda. It emphasizes environmental sampling through animal excreta and wastewater surveillance for early zoonotic detection, advocates for point-of-care polymerase chain reaction (PCR) testing platforms, and multiplex models to improve decentralized diagnostics. With 48 % of African nations incorporating One Health in national agendas, a unified continental framework is needed to support broader adoption and advance regional health security.
Antibiotic resistance profiles of oral flora in hippopotami (Hippopotamus amphibius) : implications for treatment of human bite wound infections
(BioMed Central, 2025-04) Michel, Anita Luise; Engelbrecht, Maralize; Roux, Francois; Wentzel, Jeanette Maria; Jonker, Annelize; anita.michel@up.ac.za
BACKGROUND : The common hippopotamus (Hippopotamus amphibius) is found in aquatic environments throughout sub-Saharan Africa and is known to cause attacks on humans living or working close to water bodies. Victims surviving an attack often suffer from the consequences of severe wound infections caused by the animal’s sharp canine teeth. OBJECTIVE : Isolation of normal flora bacteria from the oral cavity of common hippopotami (Hippopotamus amphibious) followed by antibiotic susceptibility testing to aid in the identification of a targeted antibiotic treatment regimen for hippopotamus attack victims. METHODS : Oral swabs were collected from 34 free-ranging hippopotami in three reserves within the Greater Kruger National Park Complex in South Africa and cultured for aerobic and anaerobic bacteria. Antibiotic susceptibility testing was conducted using the disc diffusion method (Kirby-Bauer method) and a panel of 16 antibiotic drugs representing 10 antibiotic categories. RESULTS : Culturing of 50 oral swab samples from 34 hippopotami yielded 188 aerobic isolates belonging to 30 bacterial genera and 41 bacterial species (Gram-negative: 70.7%; Gram-positive: 29.3%) and 16 obligate anaerobic isolates from two genera. Three bacterial species, namely Aeromonas hydrophila, Aeromonas sobria and Shewanella putrefaciens accounted for 52% of the aerobic isolates. The anaerobic isolates were identified as Prevotella melaninogenica and Clostridium spp. Antimicrobial susceptibility testing was performed for 112 aerobic isolates (Gram-negative: 93 (83%); Gram-positive: 19 (17%)) representing all isolated bacterial species. High levels of antibiotic resistance were observed among the Gram-negative species especially to most beta-lactam antibiotics (50.5% to 80.7%). Multidrug resistance was detected in 22.6% of Gram-negative isolates and in 24.1% of all isolates. CONCLUSIONS : This study provides the first investigation of the oral flora bacteria of the common hippopotamus. Among the 32 mostly aerobic bacterial genera the most abundant bacterial species were A. hydrophila, A. sobria and S. putrefaciens. They are typical inhabitants of the aquatic habitat of the hippopotamus and of zoonotic importance as opportunistic human pathogens. The antibiotic susceptibility profiles demonstrated that quinolones, aminoglycosides, and tetracyclines were highly efficacious against these bacterial species which otherwise showed moderate to high levels of resistance to the traditional bite wound treatment with amoxicillin/clavulanate and 1st and 2nd generation cephalosporins.
Camera trap assessment of bushpig (Potamochoerus larvatus)-domestic animal interactions and implications for pathogen transmission in rural habitats of Madagascar
(Elsevier, 2025-12) Rakotoarivony, Rianja; Payne, Ariane; Kassie, Daouda; Goodman, Steven M.; Andriamahefa, Alpha; Raliniaina, Modestine; Rakotozandrindrainy, Raphael; Jori, Ferran J.
In some rural areas of Madagascar, bushpigs (Potamochoerus larvatus) are reported to be attracted to human disturbed habitats and share the same environment with domestic animals, including pigs (Sus scrofa). Such cohabitation can facilitate the transmission of pathogens between bushpigs and other domestic animals. To assess bushpig-domestic animal interactions and their implications for pathogen transmission, 26 camera-traps were deployed for three months around 10 villages in two separate regions of western Madagascar. The camera-traps were positioned at animal attraction sites: trophic resources, resting areas, and water points, and captured 17,804 images. No direct interactions (simultaneous presence) between bushpigs and domestic species were observed after analysis of 2678 trap nights. However, 44 indirect interactions (non-simultaneous presence) were recorded. The median critical time window (CTW), calculated as the time interval between the consecutive presence of bushpigs and some domestic species, was 646 min [34–1412 min]) for pigs, 672 min for cats [range 44–886 min], and 690 min for cattle [range 584–765 min]. Such CTW estimates are shorter than the average survival rate of several infectious pathogens potentially present in the environment, including African swine fever virus, Mycobacterium bovis, and Toxoplasma gondii. Factors such as proximity to water sources and protected areas statistically increased the chances of these interactions. Our research provided novel information on the level of interaction between bushpigs and other domestic animals in anthropized rural areas and which can be used to design and implement strategies to mitigate the risk of pathogen spread at the wildlife/livestock/human interface. HIGHLIGHTS • First-ever study of bushpig-domestic animal spatio-temporal interactions in Madagascar, for which indirect contacts occur. • Frequent indirect interaction between bushpigs, cattle, and cats beyond domestic pigs. • Divergent activity patterns reduce direct bushpig-domestic pig contacts. • Pathogen transmission theoretically possible given environmental survival times.
One Health Economics approach to prevention and control of zoonotic and animal diseases - considerations for South Africa
(BioMed Central, 2025-05) Mamabolo, Manana; Machalaba, Catherine; Zantsi, Siphe; Rostal, Melinda K.; Karesh, William B.; Thompson, P.N. (Peter N.); Chaminuka, Petronella
Outbreaks of animal and zoonotic diseases in South Africa are costly and raise concerns about national biosecurity. The interconnectedness of humans, livestock, wildlife and their social and ecological environment necessitates a holistic approach to prevention, preparedness and response to zoonotic and animal diseases. One Health is an increasingly accepted approach in contemporary science and policy spheres, but with limited consideration for economic dimensions. To more fully estimate costs of animal and zoonotic diseases in the country and to explore further scope for applying a One Health economics lens, the Agricultural Research Council of South Africa, in collaboration with partners, held a One Health Economics mini-congress to provide a platform where multidisciplinary stakeholders discussed practical examples, primarily from the Southern African region. Discussions at the mini-congress centred around One Health economics and opportunities, economic insights on prevention and control of Rift Valley fever (RVF), avian influenza and other zoonotic diseases, return on investment for One Health approaches, and insights from the natural resources and animal and human health sectors. Regional and international perspectives on multi-sectoral economic analysis and financing were also shared. Key recommendations from the mini-congress included promoting coordination, co-creation and co-implemented efforts to minimize effects of One Health challenges, and including economic aspects of multi-sectoral engagement to identify and reduce trade-offs and maximize co-benefits of strategies and programmes. Integration of economics in One Health fora, research and collaboration, and promotion of communities of practice and applied training to enhance learning and knowledge exchange were also identified as important.
Strong sustainability in the SEEA and the wider indicator landscape
(Pensoft Publishers, 2025-05) Usubiaga-Liano, Arkaitz; Selomane, Odirilwe; Comte, Adrien
The System of Environmental-Economic Accounting (SEEA) remains neutral when it comes to the weak and strong sustainability worldviews. However, although its manuals do not contain any references to these concepts, it can support both through physical and monetary accounting. Given that strong sustainability is better suited to monitor environmental sustainability, we provide insights into how SEEA can contribute to promote the use of strong sustainability indicators. From a strong sustainability perspective, environmental sustainability requires identifying elements of natural capital to be preserved (critical natural capital) and at the level at which they should be preserved (reference values). SEEA and its manuals do not explicitly define the first element, but the concept of 'reference values' is implicitly embedded with the 'ecosystem condition accounts' introduced in the Ecosystem Accounting (EA) manual. As such, EA is the most relevant element of the SEEA in terms of advancing strong sustainability accounting. Given that ecosystem condition accounting is still in its early stages and that ecosystem condition is currently challenging to determine, three actions are proposed to better integrate strong sustainability in SEEA. First, the next revision of the SEEA Central Framework should be more explicit in how SEEA supports weak and strong sustainability. It should also consider how SEEA is linked to the wider indicator landscape (including the Sustainable Development Goals and the Global Biodiversity Framework). Second, ecosystem condition accounting needs to be further developed, as the more abundant extent accounts cannot capture the quality of ecosystems. Third, ecosystem condition accounting could build on other strong sustainability indicator initiatives such as Planetary Boundaries or the Environmental Sustainability Gap framework that have consistently integrated reference values in the accounting practices. These actions would provide additional means to interpret environmental sustainability beyond the direction of progress as is often the case.

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