scholarly journals Landscape disturbance impacts on Attalea butyracea palm distribution in central Panama

2020 ◽  
Author(s):  
Caitlin Mertzlufft ◽  
Marguerite Madden ◽  
Nicole Gottdenker ◽  
Julie Velasquez Runk ◽  
Azael Saldaña ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Disease Transmission ◽  
Secondary Forest ◽  
Regional Scale ◽  
Human Populations ◽  
Chi Square ◽  
Landscape Disturbance ◽  
Residential Settings ◽  
Close Proximity ◽  
Central Panama

Abstract Background: Increased Attalea butyracea palm propagation, notable for its role as key habitat for the primary Chagas disease vector in Panama, has been linked to landscape disturbance in single-palm observations in this region. Close proximity of these palms to human dwellings is proposed to increase risk of Chagas disease transmission from sylvatic transmission cycles to domestic transmission involving human populations. This study examines the relationship between landscape disturbance and mature A. butyracea spatial distribution, density, and proximity to human populations and vector and reservoir species’ movement corridors at a regional scale in a 300-km2 heterogeneous tropical landscape in central Panama.Methods: We remotely identified the locations of over 50,000 mature A. butyracea palms using high-resolution WorldView2 satellite imagery. A local Getis-Ord Gi* spatial analysis identified significant clusters of aggregated palms. Associations between palm and cluster abundance and a landscape disturbance gradient, derived from official Panama land cover data, were tested using Chi-square tests for Homogeneity and Z-test for proportions. Kruskall-Wallis non-parametric analysis of variance tests were run to assess whether palm cluster area varied by disturbance level, or whether disturbance influenced average proximity of palms and palm clusters to susceptible populations or vector movement corridors.Results: Our findings indicate a regional relationship between landscape disturbance and A. butyracea occurrence. We observe a significant increase in both individual and clustered A. butyracea in secondary forest, but a reduction of palms in agricultural settings. We do not detect evidence of any reduction in abundance of palms in residential settings. A majority of residential and commercial buildings in our study area are within vector flight distance of potential vector habitat in palm crowns.Conclusions: We observe probable anthropogenic elimination of A. butyracea palms in agricultural, but not residential, settings. Even in heavily deforested regions, significant concentrations of mature palms remain in close proximity to human establishments.

scholarly journals Landscape disturbance impacts on Attalea butyracea palm distribution in central Panama

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Caitlin E. Mertzlufft ◽  
Marguerite Madden ◽  
Nicole L. Gottdenker ◽  
Julie Velásquez Runk ◽  
Azael Saldaña ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Disease Transmission ◽  
Secondary Forest ◽  
Regional Scale ◽  
Human Populations ◽  
Chi Square ◽  
Landscape Disturbance ◽  
Residential Settings ◽  
Close Proximity ◽  
Central Panama

Abstract Background Increased Attalea butyracea palm propagation, notable for its role as key habitat for the primary Chagas disease vector in Panama, has been linked to landscape disturbance in single-palm observations in this region. Close proximity of these palms to human dwellings is proposed to increase risk of Chagas disease transmission from sylvatic transmission cycles to domestic transmission involving human populations. This study examines the relationship between landscape disturbance and mature A. butyracea spatial distribution, density, and proximity to human populations and vector and reservoir species’ movement corridors at a regional scale in a 300 km2 heterogeneous tropical landscape in central Panama. Methods We remotely identified the locations of over 50,000 mature A. butyracea palms using high-resolution WorldView2 satellite imagery. A local Getis-Ord Gi* spatial analysis identified significant clusters of aggregated palms. Associations between palm and cluster abundance and a landscape disturbance gradient, derived from official Panama land cover data, were tested using Chi-square tests for Homogeneity and Z-test for proportions. Kruskall-Wallis non-parametric analysis of variance tests were run to assess whether palm cluster area varied by disturbance level, or whether disturbance was associated with proximity of palms and palm clusters to susceptible populations or vector movement corridors. Results Our findings indicate a regional relationship between landscape disturbance and A. butyracea occurrence. We observe a significant increase in both individual and clustered A. butyracea in secondary forest, but a reduction of palms in agricultural settings. We do not detect evidence of any reduction in abundance of palms in residential settings. The majority of residential and commercial buildings in our study area are within vector flight distance of potential vector habitat in palm crowns. Conclusions We observe probable anthropogenic elimination of A. butyracea palms in agricultural, but not residential, settings. Even in heavily deforested regions, significant concentrations of mature palms remain in close proximity to human establishments.

scholarly journals Landscape disturbance impacts on Attalea butyracea palm distribution in central Panama

2020 ◽  
Author(s):  
Caitlin Mertzlufft ◽  
Marguerite Madden ◽  
Nicole Gottdenker ◽  
Julie Velasquez Runk ◽  
Azael Saldaña ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Disease Transmission ◽  
Secondary Forest ◽  
Regional Scale ◽  
Human Populations ◽  
Chi Square ◽  
Landscape Disturbance ◽  
Residential Settings ◽  
Close Proximity ◽  
Central Panama

Abstract Background: Increased Attalea butyracea palm propagation, notable for its role as key habitat for the primary Chagas disease vector in Panama, has been linked to landscape disturbance in single-palm observations in this region. Close proximity of these palms to human dwellings is proposed to increase risk of Chagas disease transmission from sylvatic transmission cycles to domestic transmission involving human populations. This study examines the relationship between landscape disturbance and mature A. butyracea spatial distribution, density, and proximity to human populations and vector and reservoir species’ movement corridors at a regional scale in a 300-km2 heterogeneous tropical landscape in central Panama.Methods: We remotely identified the locations of over 50,000 mature A. butyracea palms using high-resolution WorldView2 satellite imagery. A local Getis-Ord Gi* spatial analysis identified significant clusters of aggregated palms. Associations between palm and cluster abundance and a landscape disturbance gradient, derived from official Panama land cover data, were tested using Chi-square tests for Homogeneity and Z-test for proportions. Kruskall-Wallis non-parametric analysis of variance tests were run to assess whether palm cluster area varied by disturbance level, or whether disturbance was associated with proximity of palms and palm clusters to susceptible populations or vector movement corridors.Results: Our findings indicate a regional relationship between landscape disturbance and A. butyracea occurrence. We observe a significant increase in both individual and clustered A. butyracea in secondary forest, but a reduction of palms in agricultural settings. We do not detect evidence of any reduction in abundance of palms in residential settings. The majority of residential and commercial buildings in our study area are within vector flight distance of potential vector habitat in palm crowns.Conclusions: We observe probable anthropogenic elimination of A. butyracea palms in agricultural, but not residential, settings. Even in heavily deforested regions, significant concentrations of mature palms remain in close proximity to human establishments.

scholarly journals Landscape Disturbance Impacts on Attalea Butyracea Palm Distribution in Central Panama: Implications for Chagas Disease Transmission

2020 ◽  
Author(s):  
Caitlin Mertzlufft ◽  
Marguerite Madden ◽  
Nicole Gottdenker ◽  
Julie Velasquez Runk ◽  
Azael Saldaña ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Disease Transmission ◽  
Tropical Region ◽  
Landscape Disturbance ◽  
Residential Settings ◽  
Preferred Habitat ◽  
Increased Risk ◽  
Close Proximity ◽  
Susceptible Populations ◽  
Central Panama

Abstract Background: Chagas disease is a vector-borne zoonotic disease endemic to Latin America. In Panama, Attalea butyracea palm trees are the preferred habitat of the region’s primary Chagas disease vector (Rhodnius pallescens). Close proximity of these palms to human dwellings is linked to increased risk of Chagas disease transmission. However, these palms thrive in disturbed habitats associated with human settlement and agriculture. This study examines the relationship between landscape disturbance and mature A. butyracea spatial distribution, density, and proximity to susceptible populations and vector movement corridors in a heterogeneous tropical region in central Panama. Presence of A. butyracea does not guarantee corresponding presence of R. pallescens, but as the vectors’ preferred habitat, quantifying A. butyracea response to disturbance may provide new insight into Chagas disease transmission risks in changing landscapes. Methods: We remotely identified the locations of over 50,000 mature A. butyracea palms using high-resolution WorldView2 satellite imagery. A local Getis-Ord Gi* spatial analysis identified significant clusters of aggregated palms. Associations between palm and cluster abundance and a landscape disturbance gradient, derived from official Panama landcover data, were tested using Chi-square tests for Homogeneity and Z-test for proportions. Kruskall-Wallace non-parametric analysis of variance tests were run to assess whether palm cluster area varied by disturbance level, or whether disturbance influenced average proximity of palms and palm clusters to susceptible populations or vector movement corridors.Results: Our findings indicate a regional relationship between landscape disturbance and A. butyracea occurrence. We observe a significant increase in both individual and clustered A. butyracea in secondary forest, but a reduction in palms in agricultural settings. Notably, we do not detect evidence of any thinning in abundance of palms in residential settings. All but one household in our study area is within vector flight distance of potential vector habitat in palm crowns.Conclusions: We observe probable anthropogenic thinning of A. butyracea palms in agricultural, but not residential, settings. Even in heavily deforested regions, significant concentrations of mature palms remain in close proximity to human establishments. The potential of A. butyracea palms as a source of infectious Chagas disease vectors in this region warrants further study.

Multi-scale spatial analysis of human alveolar echinococcosis risk in China

Parasitology ◽  
2003 ◽  
Vol 127 (S1) ◽  
pp. S133-S141 ◽  
Author(s):  
F. M. DANSON ◽  
A. J. GRAHAM ◽  
D. R. J. PLEYDELL ◽  
M. CAMPOS-PONCE ◽  
P. GIRAUDOUX ◽  
...  
Keyword(s):  
Spatial Data ◽  
Disease Transmission ◽  
Spatial Scales ◽  
Regional Scale ◽  
Central China ◽  
Spatial Data Analysis ◽  
Transmission Risk ◽  
Spatial Proximity ◽  
Human Populations ◽  
Remotely Sensed Data

Risk factors for the transmission of Echinococcus multilocularis to humans operate at a range of spatial scales. Over a large area, such as China, regional scale risk is correlated with variation in climatic conditions because of its effect on the spatial distribution of landscapes that can support E. multilocularis transmission in wildlife hosts and the probability of egg survival. At a local scale of a few kilometres, or tens of kilometres, transmission risk is related to the spatial proximity of human populations and landscapes with active transmission. At the patch scale, when considering individual villages or households, human behavioural factors are important and for individuals genetic and immunological factors play a role. Satellite remote sensing can provide landscape information at a range of spatial scales and provide a spatial framework within which to examine transmission patterns. This paper reviews the application of remotely sensed data and spatial data analysis to develop a better understanding of disease transmission and shows how such data have been used to examine human alveolar echinocossosis infection patterns, at a range of spatial scales, in an endemic area in central China.

scholarly journals Home invasion of triatomines increases the risk of Chagas disease transmission in the Brazilian Amazon

2020 ◽  
Author(s):  
BRUNA DANIELE LISBOA MOTA ◽  
Vera da Costa Valente ◽  
Francisco Lúzio de Paula Ramos ◽  
Sebastião Aldo da Silva Valente ◽  
Ana Yecê das Neves Pinto
Keyword(s):  
Chagas Disease ◽  
Disease Transmission ◽  
Parasitic Infection ◽  
Cross Sectional Study ◽  
Asymptomatic Infection ◽  
The State ◽  
Human Populations ◽  
Positive Serology ◽  
Cross Sectional ◽  
Vector Behaviour

Abstract Chagas disease is a parasitic infection with a large reemergent rates in some Amazon regions with usual features of outbreaks of the acute disease mainly by oral transmission. The main vectors of Trypanosoma cruzi are hematophagous insects, the triatomines. Some of them can establish themselves in human dwellings and their annexes but others are mostly wild. In the state of Pará, few records have been made about the occurrence of those wild vectors in fortuitous contact with inhabitants in riverside regions in the Amazon. These vector behaviours have been studied by our group since 2006, trying to explain their role in transmission of the silent disease or asymptomatic infection. The objective of this study is to describe the epidemiological profile of populations exposed to random triatomine home invasion in riverside areas with this registered occurrence. This is a cross-sectional study developed in Abaetetuba city, in the state of Pará, where we conducted a seroepidemiologic survey in inhabitants that registered triatomine home invasion. The results demonstrated that triatomine invasions occur especially in the in-home environment and in the rural zone. The genus Rhodnius was the most found in residences of the municipalities. Direct contact through the vector was reported by 15.55% of the total participants, and an unusual vector behaviour were observed during the day. Despite this small casuistic, 0.47% of the enrolled inhabitants had positive serology IgG anti- T. cruzi antibodies. We confirm one occurrence of asymptomatic infection in a child and, also, favourable links to the Chagas disease transmission chain. Faced with the scarcity of information on triatomine aggression in the Amazon, the authors recommended an entomological study of greater scope in those areas. The record of unusual vector behaviour and the serological surveillance of human populations under this risk may constitute a new tool for the early detection of silent infections and reinforce the knowledges about the behaviour of invading insects. At the same time, health education can assist in strategies for the prevention of Chagas' disease.

scholarly journals Deforestation effects on Attalea palms and their resident Rhodnius, vectors of Chagas disease, in eastern Amazonia

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252071
Author(s):  
Walter Souza Santos ◽  
Rodrigo Gurgel-Gonçalves ◽  
Lourdes Maria Garcez ◽  
Fernando Abad-Franch
Keyword(s):  
Chagas Disease ◽  
Secondary Forest ◽  
Site Occupancy ◽  
Population Level ◽  
Transmission Risk ◽  
Occupancy Models ◽  
Landscape Disturbance ◽  
Vector Density ◽  
Old Growth Forest ◽  
Blood Sucking

Attalea palms provide primary habitat to Rhodnius spp., vectors of Trypanosoma cruzi. Flying from palms, these blood-sucking bugs often invade houses and can infect people directly or via food contamination. Chagas disease (CD) risk may therefore increase when Attalea palms thrive near houses. For example, Attalea dominate many deforested landscapes of eastern Amazonia, where acute-CD outbreaks are disturbingly frequent. Despite this possible link between deforestation and CD risk, the population-level responses of Amazonian Attalea and their resident Rhodnius to anthropogenic landscape disturbance remain largely uncharted. We studied adult Attalea palms in old-growth forest (OGF), young secondary forest (YSF), and cattle pasture (CP) in two localities of eastern Amazonia. We recorded 1856 Attalea along 10 transects (153.6 ha), and detected infestation by Rhodnius spp. in 18 of 280 systematically-sampled palms (33 bugs caught). Distance-sampling models suggest that, relative to OGF, adult Attalea density declined by 70–80% in CP and then recovered in YSF. Site-occupancy models estimate a strong positive effect of deforestation on palm-infestation odds (βCP-infestation = 4.82±1.14 SE), with a moderate decline in recovering YSF (βYSF-infestation = 2.66±1.10 SE). Similarly, N-mixture models suggest that, relative to OGF, mean vector density sharply increased in CP palms (βCP-density = 3.20±0.62 SE) and then tapered in YSF (βYSF-density = 1.61±0.76 SE). Together, these results indicate that disturbed landscapes may support between ~2.5 (YSF) and ~5.1 (CP) times more Attalea-dwelling Rhodnius spp. per unit area than OGF. We provide evidence that deforestation may favor palm-dwelling CD vectors in eastern Amazonia. Importantly, our landscape-disturbance effect estimates explicitly take account of (i) imperfect palm and bug detection and (ii) the uncertainties about infestation and vector density arising from sparse bug data. These results suggest that incorporating landscape-disturbance metrics into the spatial stratification of transmission risk could help enhance CD surveillance and prevention in Amazonia.

Interactions between ecological and socio-economic drivers of Buruli ulcer burden in Sub-Saharan Africa: opportunities for an improved control

2018 ◽  
Author(s):  
Andes Garchitorena ◽  
Matthew H. Bonds ◽  
Jean-Francois Guégan ◽  
Benjamin Roche
Keyword(s):  
Socioeconomic Factors ◽  
Disease Transmission ◽  
Access To Health Care ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Sub Saharan Africa ◽  
Aquatic Environments ◽  
Human Populations ◽  
Complex Interactions ◽  
Sub Saharan

This chapter provides an overview of the complex interactions between ecological and socioeconomic factors for the development and control of Buruli ulcer in Sub-Saharan Africa. We review key ecological and evolutionary processes driving the environmental persistence and proliferation of Mycobacterium ulcerans, the causative agent, within aquatic environments, as well as transmission processes from these aquatic environments to human populations. We also outline key socioeconomic factors driving the economic and health burden of Buruli ulcer in endemic regions, revealed by reciprocal feedbacks between poverty, disease transmission from exposure aquatic environments and disease progression to severe stages owing to low access to health care. The implications of such insights for disease control, both in terms of limitations of current strategies and directions for the future, are discussed.

Regional scale environmental variables complementing a Risk Model of Chagas Disease vectorial transmission

2018 ◽  
Author(s):  
Ximena Porcasi ◽  
Veronica Andreo ◽  
Anabella Ferral ◽  
Pilar Guimarey ◽  
M. Soledad Santini ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Environmental Variables ◽  
Risk Model ◽  
Regional Scale

Dynamics of an infection age-space structured cholera model with Neumann boundary condition

2021 ◽  
pp. 1-30
Author(s):  
WEIWEI LIU ◽  
JINLIANG WANG ◽  
RAN ZHANG
Keyword(s):  
Vibrio Cholerae ◽  
Disease Transmission ◽  
Global Attractivity ◽  
Neumann Boundary ◽  
Reaction Diffusion ◽  
Human Populations ◽  
Global Dynamics ◽  
Infection Age ◽  
Reaction Diffusion Model ◽  
Disease Persistence

This paper investigates global dynamics of an infection age-space structured cholera model. The model describes the vibrio cholerae transmission in human population, where infection-age structure of vibrio cholerae and infectious individuals are incorporated to measure the infectivity during the different stage of disease transmission. The model is described by reaction–diffusion models involving the spatial dispersal of vibrios and the mobility of human populations in the same domain Ω ⊂ ℝ n . We first give the well-posedness of the model by converting the model to a reaction–diffusion model and two Volterra integral equations and obtain two constant equilibria. Our result suggest that the basic reproduction number determines the dichotomy of disease persistence and extinction, which is achieved by studying the local stability of equilibria, disease persistence and global attractivity of equilibria.

scholarly journals The prevalence and clinical significance of Presymptomatic COVID-19 patients: how we can be one step ahead in mitigating a deadly pandemic

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Juen Kiem Tan ◽  
Dalleen Leong ◽  
Hemalatha Munusamy ◽  
Nor Hazwani Zenol Ariffin ◽  
Najma Kori ◽  
...  
Keyword(s):  
Clinical Significance ◽  
Disease Transmission ◽  
Temporal Dynamics ◽  
Face Mask ◽  
Chi Square ◽  
Exact Test ◽  
Atypical Symptoms ◽  
One Step ◽  
Receive Treatment ◽  
Transmission Studies

Abstract Background Presymptomatic COVID-19 patients have been identified as a major stumbling block in efforts to break the chain of transmission. Studies on temporal dynamics of its shedding suggests it peaks 1–2 days prior to any symptom onset. Therefore, a large proportion of patients are actively spreading the disease unknowingly whilst undetected. However, lengthy lockdowns and isolation leads to a host of socioeconomic issues and are impractical. Conversely, there exists no study describing this group and their clinical significance despite their key role in disease transmission. Methods As a result, we devised a retrospective study to look at the prevalence of presymptomatic patients with COVID-19 from data sourced via our medical records office. Subsequently, we identify early indicators of infection through demographic information, biochemical and radiological abnormalities which would allow early diagnosis and isolation. In addition, we will look into the clinical significance of this group and their outcome; if it differs from asymptomatic or symptomatic patients. Descriptive statistics were used in addition to tabulating the variables and corresponding values for reference. Variables are compared between the presymptomatic group and others via Chi-square testing and Fisher’s exact test, accepting a p value of < 0.05 as significant. Results Our analysis shows a higher proportion of presymptomatic patients with atypical symptoms like chest pain while symptomatic patients commonly present with respiratory symptoms like cough and shortness of breath. Besides that, there were more females presenting as presymptomatic patients compared to males (p = 0.019) and these group of patients were likely to receive treatment (p < 0.001). Otherwise, we were not able to identify other statistically significant markers suggesting a patient is presymptomatic. Conclusion As we have little means of identifying these silent spreaders, it highlights further the importance of general measures implemented to stop COVID-19 transmission like social distancing, face mask, and widespread testing.

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