Search for: All records

Purpose of Review: In this paper, we synthesize the status and trends of studies assessing the effects of landscape structure and changes on zoonotic and vector-borne disease risk in the Tropical America region (i.e., spanning from Mexico to southern South America). Understanding how landscape structure affects disease emergence is critical to designing prevention measures and maintaining healthy ecosystems for both animals and humans. Recent Findings: We found that there is a small number of articles being published each year regarding landscape structure and zoonotic and vector borne diseases in the Tropical Americas region, with a slight growing trend after 2013. We identified a large knowledge gap on the subject in most of the countries: in 15 of 27 countries, no article was found, and 72% of the current literature available is concentrated in only three countries (Brazil, Panama, and Colombia). Five diseases represent about 68% of the available knowledge, which compared to over 200 types of known zoonoses and vector-borne diseases, is an extremely low number. Most of the knowledge that exists for the region is about landscape composition, with few studies evaluating configuration parameters. Summary: In general, landscape changes presented a positive effect on zoonotic and disease risk in most of the studies found, with habitat loss, fragmentation and increases in the amount of edge habitats leading to an increased risk of the diseases investigated. The continued integration of landscape ecology into disease ecology studies can increase the knowledge about how land use change is affecting animals and human health and can allow the establishment of guidelines to create landscapes that have a low pathogenicity. 

Did you know health is not just about not being sick? It is about feeling well. In healthy ecosystems, you can find plants, animals, water, rocks, and soil, all interacting with many microbes. Thanks to this biodiversity we have clean air, fresh water, and nutritious food. Bees and other animals pollinate flowers to help grow fruits and vegetables. Birds spread seeds that grow into trees and forests. Plants clean the air we breathe. And people feel better in nature. Healthy ecosystems, therefore, keep people healthy. While public health programs teach people about healthy food and give them access to medicines, people make ecosystems healthier by protecting nature. You can help too, by taking care of your health and your surrounding ecosystem, learning about the world, and supporting decisions and actions that protect nature and people. By becoming guardians of Earth’s biodiversity, we can all have a healthy future together. 

In the Americas, wild yellow fever (WYF) is an infectious disease that is highly lethal for some non-human primate species and non-vaccinated people. Specifically, in the Brazilian Atlantic Forest, Haemagogus leucocelaenus and Haemagogus janthinomys mosquitoes act as the major vectors. Despite transmission risk being related to vector densities, little is known about how landscape structure affects vector abundance and movement. To fill these gaps, we used vector abundance data and a model-selection approach to assess how landscape structure affects vector abundance, aiming to identify connecting elements for virus dispersion in the state of São Paulo, Brazil. Our findings show that Hg. leucocelaenus and Hg. janthinomys abundances, in highly degraded and fragmented landscapes, are mainly affected by increases in forest cover at scales of 2.0 and 2.5 km, respectively. Fragmented landscapes provide ecological corridors for vector dispersion, which, along with high vector abundance, promotes the creation of risk areas for WYF virus spread, especially along the border with Minas Gerais state, the upper edges of the Serra do Mar, in the Serra da Cantareira, and in areas of the metropolitan regions of São Paulo and Campinas. 

The amphibian skin microbiome is an important component of anti-pathogen defense, but the impact of environmental change on the link between microbiome composition and host stress remains unclear. In this study, we used radiotelemetry and host translocation to track microbiome composition and function, pathogen infection, and host stress over time across natural movement paths for the forest-associated treefrog, Boana faber. We found a negative correlation between cortisol levels and putative microbiome function for frogs translocated to forest fragments, indicating strong integration of host stress response and anti-pathogen potential of the microbiome. Additionally, we observed a capacity for resilience (resistance to structural change and functional loss) in the amphibian skin microbiome, with maintenance of putative pathogen-inhibitory function despite major temporal shifts in microbiome composition. Although microbiome community composition did not return to baseline during the study period, the rate of microbiome change indicated that forest fragmentation had more pronounced effects on microbiome composition than translocation alone. Our findings reveal associations between stress hormones and host microbiome defenses, with implications for resilience of amphibians and their associated microbes facing accelerated tropical deforestation. 

Abstract Zoonotic diseases represent 75% of emerging infectious diseases worldwide, and their emergence is mainly attributed to human‐driven changes in landscapes. Land use change, especially the conversion of natural areas to agricultural use, has the potential to impact hosts and vector dynamics, affecting pathogen transmission risk. While these links are becoming better understood, very few studies have investigated the opposite question—how native vegetation restoration affects zoonotic disease outbreaks.We reviewed the existing evidence linking native vegetation restoration with zoonotic transmission risk, identified knowledge gaps, and, by focusing on tropical areas, proposed forest restoration strategies that could help in limiting the spread of zoonotic diseases.We identified a large gap in information on the effects of native vegetation restoration on zoonotic diseases, especially within tropical regions. In addition, the few studies that exist do not consider environmental aspects that can affect the outcomes of restoration on disease risk, such as the land use history and landscape structural characteristics (as composition and configuration of native habitats). Our conceptual framework raises two important points: (1) the effects of forest restoration may depend on the context of the existing landscape, especially the percentage of native vegetation existing at the beginning of the restoration; and (2) these effects will also be dependent on the spatial arrangement of the restored area within the existing landscape. Furthermore, we propose important topics to be studied in the coming years to integrate zoonotic disease risk as a criterion in restoration planning.Synthesis and application. Our results contribute to a more comprehensive forest restoration planning, comprising multiple ecosystem services and resulting in healthier landscapes for both people and nature. Our framework could be integrated into the post‐2020 global biodiversity framework targets. 

ABSTRACT Anthropogenic habitat disturbance is fundamentally altering patterns of disease transmission and immunity across the vertebrate tree of life. Most studies linking anthropogenic habitat change and disease focus on habitat loss and fragmentation, but these processes often lead to a third process that is equally important:habitat split. Defined as spatial separation between the multiple classes of natural habitat that many vertebrate species require to complete their life cycles, habitat split has been linked to population declines in vertebrates, e.g. amphibians breeding in lowland aquatic habitats and overwintering in fragments of upland terrestrial vegetation. Here, we link habitat split to enhanced disease risk in amphibians (i) by reviewing the biotic and abiotic forces shaping elements of immunity and (ii) through a spatially oriented field study focused on tropical frogs. We propose a framework to investigate mechanisms by which habitat split influences disease risk in amphibians, focusing on three broad host factors linked to immunity: (i) composition of symbiotic microbial communities, (ii) immunogenetic variation, and (iii) stress hormone levels. Our review highlights the potential for habitat split to contribute to host‐associated microbiome dysbiosis, reductions in immunogenetic repertoire, and chronic stress, that often facilitate pathogenic infections and disease in amphibians and other classes of vertebrates. We highlight that targeted habitat‐restoration strategies aiming to connect multiple classes of natural habitats (e.g. terrestrial–freshwater, terrestrial–marine, marine–freshwater) could enhance priming of the vertebrate immune system through repeated low‐load exposure to enzootic pathogens and reduced stress‐induced immunosuppression.