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.

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 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 ◽  
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.

Detection Probability and Site Occupancy of the Granular Spiny Frog (Quasipaa verrucospinosa) in the Tropical Rain Forests of Bach Ma National Park, Central Vietnam

2020 ◽  
Vol 27 (1) ◽  
pp. 26-32
Author(s):  
Binh Van Ngo ◽  
Ya-Fu Lee ◽  
Chung D. Ngo
Keyword(s):  
National Park ◽  
Large Scale ◽  
Secondary Forest ◽  
Site Occupancy ◽  
Weather Conditions ◽  
Primary Forest ◽  
Occupancy Models ◽  
Tropical Rain Forests ◽  
Amphibian Species ◽  
Central Vietnam

Amphibian species are rarely detected with perfect accuracy, regardless of the method employed. A large-scale assessment for Quasipaa verrucospinosa occupancy was conducted at 35 sites in the primary forest and 42 sites in the secondary forest of Bach Ma National Park, central Vietnam. Based on the detection data for each site, the distribution of Q. verrucospinosa was estimated in different habitat types using occupancy models. From the best model among all performed models, we estimated a site occupancy probability of 0.576 that was higher than the naive occupancy estimate of 0.403 and a 43.1% increase over the site proportion at which Q. verrucospinosa was actually observed. The site covariate of the primary forest was an important determinant of site occupancy, which was not associated with the variable of secondary forest. In a combined AIC model weight: the p(temperature), p(humidity), and p(precipitation) models have 47.3, 67.1, and 90.9% of the total, respectively; providing evidence that aforementioned environmental conditions were important sample covariates in modelling detection probabilities of Q. verrucospinosa. Our results substantiate the importance of incorporating detection and occupancy probabilities into studies of habitat relationships and suggest that the primary forests associated with weather conditions influence the site occupancy of Q. verrucospinosa in Bach Ma National Park, central Vietnam.

An entomological and seroepidemiological study of the vectorial-transmission risk of Chagas disease in the coast of northern Chile

2015 ◽  
Vol 29 (4) ◽  
pp. 387-392 ◽  
Author(s):  
C. R. GONZÁLEZ ◽  
C. REYES ◽  
A. CANALS ◽  
A. PARRA ◽  
X. MUÑOZ ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Transmission Risk ◽  
Northern Chile

scholarly journals Identifying Current and Missing Knowledge in the Control of Pyrethroid-Resistant Triatoma infestans, Vector of Chagas Disease

2017 ◽  
Vol 9 (7) ◽  
pp. 47
Author(s):  
Gonzalo Roca Acevedo ◽  
María Inés Picollo
Keyword(s):  
Chagas Disease ◽  
Chemical Control ◽  
Rational Design ◽  
Pyrethroid Resistance ◽  
Triatoma Infestans ◽  
Vector Transmission ◽  
Pyrethroid Insecticides ◽  
Blood Sucking ◽  
Deltamethrin Resistance ◽  
Metabolic Detoxification

Triatomines are blood-sucking bugs that occur mainly in Latin America. They are vectors of Trypanosoma cruzi, the parasite that causes Chagas disease. Chemical control of Chagas disease´s vectors by using pyrethroid insecticides has been highly successful for the elimination of domestic infestation and consequently the reduction of the vector transmission. However, at the beginning of the 2000s a decrease in the effectiveness of the chemical control of triatomines was detected in several areas from Argentina and Bolivia, particularly in the Gran Chaco eco-region.During the last 15 years, several studies demonstrated the evolution of insecticide resistance in Triatoma infestans and established the presence of different toxicological profiles, the autosomal inherence of resistance, the biological costs of deltamethrin resistance, the expression of deltamethrin resistance thorough the embryonic development, and the main mechanisms of resistance (target-site insensitivity and metabolic detoxification of insecticides).The emergence of pyrethroid resistance coupled with the usual difficulties in sustaining adequate rates of insecticide applications emphasize the need of incorporating other tools for integrated vector and disease control, such as the proposal of the organo-phosphorus insecticide fenitrothion as an alternative chemical strategy for the management of the resistance because it was effective against pyrethroid-resistant populations in laboratory and semi-field trials.New studies on the current situation of presence and spread of resistant populations of triatomines and the acceptance of the use of alternative insecticides are critical requirements in the implementation of strategies for the management of resistance and for the rational design of campaigns oriented to reducing the vector transmission of Chagas’ disease.

scholarly journals Transmission heterogeneities, kinetics, and controllability of SARS-CoV-2

Science ◽  
2020 ◽  
pp. eabe2424 ◽  
Author(s):  
Kaiyuan Sun ◽  
Wei Wang ◽  
Lidong Gao ◽  
Yan Wang ◽  
Kaiwei Luo ◽  
...  
Keyword(s):  
Social Interactions ◽  
Population Level ◽  
Transmission Risk ◽  
Contact Tracing ◽  
Symptom Presentation ◽  
Secondary Infections ◽  
The Family ◽  
Infectious Disease Dynamics ◽  
Kinetics Of

A long-standing question in infectious disease dynamics concerns the role of transmission heterogeneities, driven by demography, behavior and interventions. Based on detailed patient and contact tracing data in Hunan, China we find 80% of secondary infections traced back to 15% of SARS-CoV-2 primary infections, indicating substantial transmission heterogeneities. Transmission risk scales positively with the duration of exposure and the closeness of social interactions and is modulated by demographic and clinical factors. The lockdown period increases transmission risk in the family and households, while isolation and quarantine reduce risks across all types of contacts. The reconstructed infectiousness profile of a typical SARS-CoV-2 patient peaks just before symptom presentation. Modeling indicates SARS-CoV-2 control requires the synergistic efforts of case isolation, contact quarantine, and population-level interventions, owing to the specific transmission kinetics of this virus.

The Octopamine Receptor Is a Possible Target for Eugenol-Induced Hyperactivity in the Blood-Sucking Bug Triatoma infestans (Hemiptera: Reduviidae)

2019 ◽  
Author(s):  
Mercedes M N Reynoso ◽  
Alejandro Lucia ◽  
Eduardo N Zerba ◽  
Raúl A Alzogaray
Keyword(s):  
Drosophila Melanogaster ◽  
Latin America ◽  
Essential Oils ◽  
Chagas Disease ◽  
American Cockroach ◽  
Triatoma Infestans ◽  
Aromatic Plants ◽  
Blood Sucking ◽  
Site Of Action ◽  
Octopamine Receptor

Abstract Eugenol is a major component of the essential oils in cloves and other aromatic plants. In insects, it produces toxic effects and repellency, and there is evidence that its site of action is the octopamine receptor. The objective of the present study was to explore whether the octopamine receptor is involved in the hyperactivity produced by eugenol in the blood-sucking bug Triatoma infestans (Klug). This insect is the main vector of Chagas disease in Latin America. Four treatments were topically applied on third instar nymphs: 1) octopamine, 2) eugenol, 3) phentolamine hydrochloride (an antagonist of the octopamine receptor) followed by octopamine, and 4) phentolamine hydrochloride followed by eugenol. Both octopamine and eugenol hyperactivated the nymphs. However, pretreatment with phentolamine hydrochloride inhibited the hyperactivating effect of both compounds. These results are in agreement with previous works on Drosophila melanogaster (Meigen) (Diptera: Drosophilidae) and the American cockroach. They suggest that the octopamine receptor is a possible site of action for eugenol.

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