Journal Articles

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915

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Author: search.filters.author.Muylaert RL

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    Leptospirosis in Campinas, Brazil: The interplay between drainage, impermeable areas, and social vulnerability
    (PLOS (Public Library of Science), California, United States of America, 2025-09) de Azevedo TSDD; Nisa S; Littlejohn S; Muylaert RL; Gomes-Solecki M
    Leptospirosis is an epidemic disease caused by bacteria of the Leptospira genus. Its risk is closely associated with inadequate sanitation and flooding, a common public health challenge in large urban centers together with urban environmental modifications, and socio-economic factors. This retrospective observational research investigated the association between the distribution of leptospirosis cases and three contextual factors, drainage, soil impermeability and social vulnerability in Campinas city, São Paulo, Brazil. We hypothesized that the number of cases will increase in areas that are impermeable and in proximity to drainage systems as well as where social vulnerability is high. We investigated the associations based on 86 autochthonous cases, comparing cases where infection risk was linked to contact with floodwater or mud (n = 54) to cases associated with other exposures (n = 32). Spatial statistics were used to map disease distribution and investigate the relationship between leptospirosis cases and contextual factors. Our results indicate that leptospirosis cases density rises near drainage systems, peaking at 200 m. Risk is elevated in socially vulnerable areas, particularly where floodwater or mud exposure is high, and in highly impermeable areas. This study demonstrated that leptospirosis risk remains highly determined by living and working conditions. These findings support targeted strategies to deliver effective prevention, treatment and control interventions in highly populated urban areas of the Global South and similar contexts. Furthermore, combining local contextual environmental information with spatial analysis produces relevant evidence for guiding health public policy and spatial planning and provides precise parameters for future epidemiological models and prevention actions.
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    Upscaling effects on infectious disease emergence risk emphasize the need for local planning in primary prevention within biodiversity hotspots
    (Springer Nature Limited, 2025-10-27) Muylaert RL; Wilkinson DA; Dwiyanti EI; Hayman DTS
    Zoonotic risk assessments are increasingly vital in the wake of recent epidemics. The microbial diversity of parasitic organisms correlates with host species richness, with regions of high biodiversity facing elevated risks of emerging zoonotic infections. While habitat loss and fragmentation reduce species diversity, anthropogenic encroachment, particularly in forested areas, amplifies human exposure to novel pathogens. This study integrates host habitat, biodiversity, human encroachment, and population at risk to estimate novel disease emergence and epidemic risk at multiple spatial scales. Using Java, Indonesia, as a case study, we demonstrate that degrading spatial resolution leads to information loss, with optimal resolutions typically below 2000 m, ideally around 500 m when native-resolution processing is unfeasible. Gravity models of epidemic spread highlight Jakarta and West Java as high-risk areas, with varying contributions from surrounding regions. Our spatial analysis underscores the influence of population centers on forest management and agroforestry practices. These findings offer valuable insights for guiding pandemic prevention research and improving pathogen- and driver-based risk monitoring strategies.
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    Spatial risk of pathogen transmission from cattle to vulnerable and endangered wild bovids in Thailand
    (Wiley Periodicals LLC on behalf of Society for Conservation Biology, 2025-08-12) Horpiencharoen W; Marshall JC; Muylaert RL; John RS; Hayman DTS
    The interaction between livestock and wildlife causes challenges for wildlife conservation and public health. Mapping interface areas is essential for prioritizing disease surveillance, implementing mitigation measures, and developing targeted control programs to protect threatened wildlife. We used spatial overlays of habitat suitability to predict interface areas with high risk of pathogen transmission for three Thai wild bovids (gaur [Bos gaurus], banteng [Bos javanicus] and wild water buffalo [Bubalus arnee]) and domestic cattle. We assumed that domestic cattle are the reservoir of important bovine infectious diseases and that high cattle density is a proxy for a higher transmission risk. We calculated the interface inside and outside Thai protected areas and classified these by land use types. Then, we counted the number of bovine infectious disease occurrences reported in high-risk areas. Our study indicated that the highest risk areas for these species are at the forest edges where high habitat suitability and cattle densities overlap. Suitable habitats for wild water buffalo had the largest proportion of high-risk areas (9%), while gaur and banteng had similar risk areas (4%). Kuiburi National Park had the largest risk area (274 km2) for gaur and banteng, whereas the largest risk area for wild water buffalo overlapped with Huai Thabthan-Had Samran by 126 km2. Cropland and unclassified forests had the highest percentage of interface areas, indicating a higher risk of pathogen transmission. Our results highlight how habitat suitability analyses could help infectious disease prevention and control strategies and may also support wild bovid conservation initiatives.
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    Land Use Change and Infectious Disease Emergence
    (John Wiley and Sons, Inc on behalf of the American Geophysical Union, 2025-06-01) Rulli MC; D’Odorico P; Galli N; John RS; Muylaert RL; Santini M; Hayman DTS
    Major infectious diseases threatening human health are transmitted to people from animals or by arthropod vectors such as insects. In recent decades, disease outbreaks have become more common, especially in tropical regions, including new and emerging infections that were previously undetected or unknown. Even though there is growing awareness that altering natural habitats can lead to disease outbreaks, the link between land use change and emerging diseases is still often overlooked and poorly understood. Land use change typically destroys natural habitat and alters landscape composition and configuration, thus altering wildlife population dynamics, including those of pathogen hosts, domesticated (often intermediary) hosts, infectious agents, and their vectors. Moreover, land use changes provide opportunities for human exposure to direct contact with wildlife, livestock, and disease-carrying vectors, thereby increasing pathogen spillover from animals to humans. Here we explore the nexus between human health and land use change, highlighting multiple pathways linking emerging disease outbreaks and deforestation, forest fragmentation, urbanization, agricultural expansion, intensified farming systems, and concentrated livestock production. We connect direct and underlying drivers of land use change to human health outcomes related to infectious disease emergence. Despite growing evidence of land-use induced spillover, strategies to reduce the risks of emerging diseases are often absent from discussions on sustainable food systems and land management. A “One Health” perspective—integrating human, animal, and environmental health—provides a critical yet often-overlooked dimension for understanding the health impacts of land use change.
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    Impact of Infectious Diseases on Wild Bovidae Populations in Thailand: Insights from Population Modelling and Disease Dynamics
    (2023-08-31) Horpiencharoen W; Marshall JC; Muylaert RL; John RS; Hayman DTS
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    Mapping threatened Thai bovids provides opportunities for improved conservation outcomes in Asia
    (2023-08-27) Horpiencharoen W; Muylaert RL; Marshall JC; John RS; Lynam AJ; Riggio A; Godfrey A; Ngoprasert D; Gale GA; Ash E; Bisi F; Cremonesi G; Clements GR; Yindee M; Shwe NM; Pin C; Gray TNE; Aung SS; Nakbun S; Manka SG; Steinmetz R; Phoonjampa R; Seuaturien N; Phumanee W; Hayman DTS
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    Mapping threatened Thai bovids provides opportunities for improved conservation outcomes in Asia.
    (The Royal Society, 2024-09-25) Horpiencharoen W; Muylaert RL; Marshall JC; John RS; Lynam AJ; Riggio A; Godfrey A; Ngoprasert D; Gale GA; Ash E; Bisi F; Cremonesi G; Clements GR; Yindee M; Shwe NM; Pin C; Gray TNE; Aung SS; Nakbun S; Manka SG; Steinmetz R; Phoonjampa R; Seuaturien N; Phumanee W; Hayman DTS
    Wild bovids provide important ecosystem functions as seed dispersers and vegetation modifiers. Five wild bovids remain in Thailand: gaur (Bos gaurus), banteng (Bos javanicus), wild water buffalo (Bubalus arnee), mainland serow (Capricornis sumatraensis) and Chinese goral (Naemorhedus griseus). Their populations and habitats have declined substantially and become fragmented by land-use change. We use ecological niche models to quantify how much potential suitable habitat for these species remains within protected areas in Asia and then specifically Thailand. We combined species occurrence data from several sources (e.g. mainly camera traps and direct observation) with environmental variables and species-specific and single, large accessible areas in ensemble models to generate suitability maps, using out-of-sample predictions to validate model performance against new independent data. Gaur, banteng and buffalo models showed reasonable model accuracy throughout the entire distribution (greater than or equal to 62%) and in Thailand (greater than or equal to 80%), whereas serow and goral models performed poorly for the entire distribution and in Thailand, though 5 km movement buffers markedly improved the performance for serow. Large suitable areas were identified in Thailand and India for gaur, Cambodia and Thailand for banteng and India for buffalo. Over 50% of suitable habitat is located outside protected areas, highlighting the need for habitat management and conflict mitigation outside protected areas.
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    Using drivers and transmission pathways to identify SARS-like coronavirus spillover risk hotspots.
    (Springer Nature Limited, 2023-10-27) Muylaert RL; Wilkinson DA; Kingston T; D'Odorico P; Rulli MC; Galli N; John RS; Alviola P; Hayman DTS
    The emergence of SARS-like coronaviruses is a multi-stage process from wildlife reservoirs to people. Here we characterize multiple drivers-landscape change, host distribution, and human exposure-associated with the risk of spillover of zoonotic SARS-like coronaviruses to help inform surveillance and mitigation activities. We consider direct and indirect transmission pathways by modeling four scenarios with livestock and mammalian wildlife as potential and known reservoirs before examining how access to healthcare varies within clusters and scenarios. We found 19 clusters with differing risk factor contributions within a single country (N = 9) or transboundary (N = 10). High-risk areas were mainly closer (11-20%) rather than far ( < 1%) from healthcare. Areas far from healthcare reveal healthcare access inequalities, especially Scenario 3, which includes wild mammals and not livestock as secondary hosts. China (N = 2) and Indonesia (N = 1) had clusters with the highest risk. Our findings can help stakeholders in land use planning, integrating healthcare implementation and One Health actions.
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    Impact of infectious diseases on wild bovidae populations in Thailand: insights from population modelling and disease dynamics.
    (The Royal Society, 2024-07-03) Horpiencharoen W; Marshall JC; Muylaert RL; John RS; Hayman DTS
    The wildlife and livestock interface is vital for wildlife conservation and habitat management. Infectious diseases maintained by domestic species may impact threatened species such as Asian bovids, as they share natural resources and habitats. To predict the population impact of infectious diseases with different traits, we used stochastic mathematical models to simulate the population dynamics over 100 years for 100 times in a model gaur (Bos gaurus) population with and without disease. We simulated repeated introductions from a reservoir, such as domestic cattle. We selected six bovine infectious diseases; anthrax, bovine tuberculosis, haemorrhagic septicaemia, lumpy skin disease, foot and mouth disease and brucellosis, all of which have caused outbreaks in wildlife populations. From a starting population of 300, the disease-free population increased by an average of 228% over 100 years. Brucellosis with frequency-dependent transmission showed the highest average population declines (-97%), with population extinction occurring 16% of the time. Foot and mouth disease with frequency-dependent transmission showed the lowest impact, with an average population increase of 200%. Overall, acute infections with very high or low fatality had the lowest impact, whereas chronic infections produced the greatest population decline. These results may help disease management and surveillance strategies support wildlife conservation.
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    Hantavirus Expansion Trends in Natural Host Populations in Brazil.
    (MDPI (Basel, Switzerland), 2024-07-17) Mello JHF; Muylaert RL; Grelle CEV; Kemenesi G; Kurucz K
    Hantaviruses are zoonotic agents responsible for causing Hantavirus Cardiopulmonary Syndrome (HCPS) in the Americas, with Brazil ranking first in number of confirmed HCPS cases in South America. In this study, we simulate the monthly spread of highly lethal hantavirus in natural hosts by conjugating a Kermack-McCormick SIR model with a cellular automata model (CA), therefore simultaneously evaluating both in-cell and between-cell infection dynamics in host populations, using recently compiled data on main host species abundances and confirmed deaths by hantavirus infection. For both host species, our models predict an increase in the area of infection, with 22 municipalities where no cases have been confirmed to date expected to have at least one case in the next decade, and a reduction in infection in 11 municipalities. Our findings support existing research and reveal new areas where hantavirus is likely to spread within recognized epicenters. Highlighting spatial-temporal trends and potential expansion, we emphasize the increased risk due to pervasive habitat fragmentation and agricultural expansion. Consistent prevention efforts and One Health actions are crucial, especially in newly identified high-risk municipalities.