Biology subjects

Muylaert, R. L.

Publications and source records attributed to Muylaert, R. L..

7 recordsLinked to original sources

bioRxiv2024

Flood-related cases of leptospirosis in Campinas, Brazil: the interplay between drainage, impermeable areas and social vulnerability

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, Sao 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 83 autochthonous cases, comparing cases where infection risk was linked to contact with floodwater or mud (n=54) to cases associated with other exposures (n=29). Spatial statistics were used to map disease distribution and investigate the relationship between leptospirosis cases and contextual factors. Our results indicate that the density of leptospirosis increases near drainage systems with risk peaking at 200 m, in areas of greater social vulnerability with increased risk due to floodwater or mud exposure in highly vulnerable regions, and in highly waterproofed urban 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. Author summaryThis study explores the links between environmental and contextual factors that influence the risk of leptospirosis transmission to humans in Campinas, Sao Paulo, Brazil. Leptospirosis is an infectious disease caused by the Leptospira bacteria. We investigated how drainage systems, impermeable soil area, and social vulnerability contribute to disease distribution, using spatial statistics to map spatial conditions for 83 cases associated with water and mud contact and other risks. Our findings highlight how environmental and socio-economic factors intersect to influence public health, shedding light on the role of urban planning and drainage infrastructure in the transmission risk of infectious diseases. This interdisciplinary approach underscores the importance of considering social and environmental contexts when developing public health strategies, aligning with broader global efforts to address diseases linked to urbanization and environmental changes. Our study advances the understanding of how spatial data and environmental factors can guide more precise parameters for epidemiological models, offering insights into disease control interventions. We discuss the role of prevention, flood management, and equitable infrastructure in safeguarding public health, emphasizing how the environment shapes health risks. This research provides practical recommendations for helping decision-makers prioritize areas for intervention to reduce the burden of leptospirosis, particularly in vulnerable communities.

ecology↗

bioRxiv2024

Spatial risk of disease transmission between wild bovids and livestock in Thailand

The livestock-wildlife interface is one of the most essential issues threatening wildlife conservation and public health. Identifying interface areas can help to prioritise disease surveillance and implement mitigation measures and control programs for targeting threatened wildlife. We predicted interface areas which were assumed to be areas at risk of infectious disease transmission based on the spatial overlap between three Thai wild bovids (including gaur, banteng and wild water buffalo) habitat suitability and domestic cattle. We assumed that domestic cattle are the reservoir of bovine infectious disease, and that high cattle density is a proxy for a higher risk of disease transmission. Our study indicated that the highest risk areas for the native species are at the forest edges where overlap exists between high habitat suitability and high cattle density. Wild water buffalo showed the largest proportion of high-risk areas (8%), while gaur and banteng showed similar risk areas (4%) in Thailand. The largest proportion of risk areas overlapping with protected areas was Namtok Sam Lan PAs at 89% for gaur, 84% for banteng and 65% for wild water buffalo. Kuiburi NP has the largest risk area around 274 km2 (around 28% of the total protected area) for gaur and banteng, whereas wild water buffalo has the largest risk area overlapping with Huai Thabthan-Had Samran around 126 km2 (10% of the PA). Kaengkrachan Forest Complex showed the second largest risk area from 249 km2 for gaur and 273 km2 for banteng (8-9% of the PA). Our results address how habitat suitability might be helpful for infectious disease prevention and control strategies focused on native fauna and One Health. Furthermore, this work may also support the wild bovid habitat conservation initiatives and land use planning by informing decision-making about balancing wildlife habitats and livestock farming.

ecology↗

bioRxiv2023

The Atlantic Forest of South America: spatiotemporal dynamic of remaining vegetation and implications for conservation

The Atlantic Forest in South America (AF) is one of the worlds most diverse and threatened biodiversity hotspots. We present a comprehensive spatiotemporal analysis of 34 years of AF landscape change between 1986-2020. We analyzed landscape metrics of forest vegetation only (FV), forest plus other natural vegetation (NV), and investigated the sensitivity of metrics to linear infrastructure. Currently, remnants comprise about 23% of FV and 36% of NV, and have decreased by 2.4% and 3.6% since 1986, respectively. Linear infrastructure negatively affected large fragments (>500,000 ha) by breaking them apart. Our findings suggest that AF protection legislation adopted in mid-2005 has taken effect: between 1986-2005, there was a loss of FV and NV (3% and 3.45%) and a decrease in the number of FV and NV fragments (8.6% and 8.3%). Between 2005-2020, there was a relative recovery of FV (1 Mha; 0.6%), slight loss of NV (0.25 Mha; 0.15%) and increase in the number of FV and NV fragments (12% and 9%). Still, 97% of the vegetation fragments are small (<50 ha), with an average fragment size between 16 and 26 ha. Furthermore, 50-60% of the vegetation is <90 m from its edges, and the isolation between fragments is high (250-830 m). Alarmingly, protected areas and indigenous territories cover only 10% of the AF and are very far from any fragments (>10 km). Our work highlights the importance of legislation and landscape dynamics analysis to help monitor and keep track of AF biodiversity conservation and restoration programs in the future. HighlightsO_LIThere is 23% forest and 36% natural vegetation cover remaining in the Atlantic Forest. C_LIO_LIBetween 1986-2020, native forest cover decreased by 2.4% and natural vegetation by 3.6%. C_LIO_LISince 2005, there has been a 1 Mha increase in forest area by small fragments (1 ha). C_LIO_LIRoads and railways reduced by 56%-89% fragment size, especially on large fragments. C_LIO_LIAlarmingly, 97% of fragments are small (<50 ha) and 60% are under edge effect (<90 m). C_LI

ecology↗

bioRxiv2022

Transboundary hotspots associated with SARS-like coronavirus spillover risk: implications for mitigation

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 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 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.

ecology↗

bioRxiv2021

Present and future distribution of bat hosts of sarbecoviruses: implications for conservation and public health

Global changes in response to human encroachment into natural habitats and carbon emissions are driving the biodiversity extinction crisis and increasing disease emergence risk. Host distributions are one critical component to identify areas at risk of spillover, and bats act as reservoirs of diverse viruses. We developed a reproducible ecological niche modelling pipeline for bat hosts of SARS-like viruses (subgenus Sarbecovirus), given that since SARS-CoV-2 emergence several closely-related viruses have been discovered and sarbecovirus-host interactions have gained attention. We assess sampling biases and model bats current distributions based on climate and landscape relationships and project future scenarios. The most important predictors of species distribution were temperature seasonality and cave availability. We identified concentrated host hotspots in Myanmar and projected range contractions for most species by 2100. Our projections indicate hotspots will shift east in Southeast Asia in >2 {degrees}C hotter locations in a fossil-fueled development future. Hotspot shifts have implications for conservation and public health, as loss of population connectivity can lead to local extinctions, and remaining hotspots may concentrate near human populations.

ecology↗

bioRxiv2021

Community health and human-animal contacts on the edges of Bwindi Impenetrable National Park, Uganda

Cross-species transmission of pathogens is intimately linked to human and environmental health. With limited healthcare and challenging living conditions, people living in poverty may be particularly susceptible to endemic and emerging diseases. Similarly, wildlife is impacted by human influences, including pathogen sharing, especially for species in close contact with people and domesticated animals. Here we investigate human and animal contacts and human health in a community living around the Bwindi Impenetrable National Park (BINP), Uganda. We used contact and health survey data to identify opportunities for cross-species pathogen transmission, focusing mostly on people and the endangered mountain gorilla. We conducted a survey with background questions and self-reported diaries to investigate 100 participants health, such as symptoms and behaviours, and contact patterns, including direct contacts and sightings over a week. Contacts were revealed through networks, including humans, domestic, peri-domestic, and wild animals for 1) network of contacts seen in the week of background questionnaire completion, 2) network of contacts seen during the diary week. Participants frequently felt unwell during the study, reporting from one to 10 disease symptoms at different intensity levels (maximum of seven symptoms in one day), with severe symptoms comprising 6.4% of the diary records and tiredness and headaches the most common symptoms. Besides human-human contacts, direct contacts with livestock and peri-domestic animals were the most common. Wildlife contacts were the rarest, including one direct contact with gorilla with a concerning timeline of reported symptoms. The contact networks were moderately connected and revealing a preference in contacts within the same species or taxon and within their groups. Despite sightings of wildlife being much more common than touching, one participant declared direct contact with a mountain gorilla during the week. Gorillas were seen very close to six animal taxa (including themselves) considering all interaction types, mostly seen closer to other gorillas, but also people and domestic animals. Our findings reveal a local human population with recurrent symptoms of illness in a location with intense exposure to factors that can increase pathogen transmission, such as direct contact with domestic and wild animals and proximity among animal species. Despite significant biases and study limitations, the information generated here can guide future studies, such as models for disease spread and One Health interventions.

ecology↗

bioRxiv2018

Insights on the assembly rules of a continent-wide multilayer network

Introductory paragraphHow are ecological systems assembled? Here, we aim to contribute to answering this question by harnessing the framework of a novel integrative hypothesis. We shed light on the assembly rules of a multilayer network formed by frugivory and nectarivory interactions between bats and plants in the Neotropics. Our results suggest that, at a large scale, phylogenetic trade-offs separate species into different layers and modules. At an intermediate scale, the modules are also shaped by geographic trade-offs. And at a small scale, the network shifts to a nested structure within its modules, probably as a consequence of resource breadth processes. Finally, once the topology of the network is shaped, morphological traits related to consuming fruits or nectar determine which species are central or peripheral. Our results help understand how different processes contribute to the assemblage of ecological systems at different scales, resulting in a compound topology.

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