H Marcelo Aguilar V - Academia.edu (original) (raw)
Papers by H Marcelo Aguilar V
Memórias do Instituto Oswaldo Cruz, 2001
PLOS Neglected Tropical Diseases, Mar 2, 2010
Background: Failure to detect a disease agent or vector where it actually occurs constitutes a se... more Background: Failure to detect a disease agent or vector where it actually occurs constitutes a serious drawback in epidemiology. In the pervasive situation where no sampling technique is perfect, the explicit analytical treatment of detection failure becomes a key step in the estimation of epidemiological parameters. We illustrate this approach with a study of Attalea palm tree infestation by Rhodnius spp. (Triatominae), the most important vectors of Chagas disease (CD) in northern South America. Methodology/Principal Findings: The probability of detecting triatomines in infested palms is estimated by repeatedly sampling each palm. This knowledge is used to derive an unbiased estimate of the biologically relevant probability of palm infestation. We combine maximum-likelihood analysis and information-theoretic model selection to test the relationships between environmental covariates and infestation of 298 Amazonian palm trees over three spatial scales: region within Amazonia, landscape, and individual palm. Palm infestation estimates are high (40-60%) across regions, and well above the observed infestation rate (24%). Detection probability is higher (,0.55 on average) in the richest-soil region than elsewhere (,0.08). Infestation estimates are similar in forest and rural areas, but lower in urban landscapes. Finally, individual palm covariates (accumulated organic matter and stem height) explain most of infestation rate variation. Conclusions/Significance: Individual palm attributes appear as key drivers of infestation, suggesting that CD surveillance must incorporate local-scale knowledge and that peridomestic palm tree management might help lower transmission risk. Vector populations are probably denser in rich-soil sub-regions, where CD prevalence tends to be higher; this suggests a target for research on broad-scale risk mapping. Landscape-scale effects indicate that palm triatomine populations can endure deforestation in rural areas, but become rarer in heavily disturbed urban settings. Our methodological approach has wide application in infectious disease research; by improving eco-epidemiological parameter estimation, it can also significantly strengthen vector surveillance-control strategies.
Parasites & Vectors, 2021
An amendment to this paper has been published and can be accessed via the original article.
Memórias do Instituto Oswaldo Cruz, 2002
Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Li... more Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Live-baited adhesive traps were tested in various ecosystems and different triatomine habitats (arboreal and terrestrial). The trials were always successful, with a rate of positive habitats generally over 20% and reaching 48.4% for palm trees of the Amazon basin. Eleven species of Triatominae belonging to the three genera of public health importance (Triatoma, Rhodnius and Panstrongylus) were captured. This trapping system provides an effective way to detect the presence of triatomines in terrestrial and arboreal silvatic habitats and represents a promising tool for ecological studies. Various lines of research are contemplated to improve the performance of this trapping system.
Memórias do Instituto Oswaldo Cruz, 2007
The risk that Chagas disease becomes established as a major endemic threat in Amazonia (the world... more The risk that Chagas disease becomes established as a major endemic threat in Amazonia (the world´s largest tropical biome, today inhabited by over 30 million people) relates to a complex set of interacting biological and social determinants. These include intense immigration from endemic areas (possibly introducing parasites and vectors), extensive landscape transformation with uncontrolled deforestation, and the great diversity of wild Trypanosoma cruzi reservoir hosts and vectors (25 species in nine genera), which maintain intense sylvatic transmission cycles. Invasion of houses by adventitious vectors (with infection rates > 60%) is common, and focal adaptation of native triatomines to artificial structures has been reported. Both acute (~ 500) and chronic cases of autochthonous human Chagas disease have been documented beyond doubt in the region. Continuous, low-intensity transmission seems to occur throughout the Amazon, and generates a hypoendemic pattern with seropositivity rates of ~ 1-3%. Discrete foci also exist in which transmission is more intense (e.g., in localized outbreaks probably linked to oral transmission) and prevalence rates higher. Early detection-treatment of acute cases is crucial for avoiding further dispersion of endemic transmission of Chagas disease in Amazonia, and will require the involvement of malaria control and primary health care systems. Comprehensive eco-epidemiological research, including prevalence surveys or the characterization of transmission dynamics in different ecological settings, is still needed. The International Initiative for Chagas Disesae Surveillance and Prevention in the Amazon provides the framework for building up the political and scientific cooperation networks required to confront the challenge of preventing Chagas disease in Amazonia.
Memórias do Instituto Oswaldo Cruz, 2002
Rhodnius ecuadoriensis infests peridomiciles and colonises houses in rural southern Ecuador. Six ... more Rhodnius ecuadoriensis infests peridomiciles and colonises houses in rural southern Ecuador. Six out of 84 dwellings (7%) surveyed in a rural village were infested (78 bugs/infested domicile; 279 bugs were collected in a single dwelling). Precipitin tests revealed R. ecuadoriensis fed on birds (65%), rodents (31%), marsupials (8%), and humans (15%)-mixed bloodmeals detected in 37.5% of individual samples. Trypanosoma cruzi from opossums and rodents may thus be introduced into the domestic cycle. Wasp parasitoidism was detected in 6.5% of 995 R. ecuadoriensis eggs (only in peridomestic habitats). Control strategies should integrate insecticide spraying (indoors and peridomestic), better management of poultry, and housing improvements. A possible inefficacy of Malathion is reported.
Parasites & Vectors, 2021
Background Triatomine bugs, the vectors of Chagas disease, associate with vertebrate hosts in hig... more Background Triatomine bugs, the vectors of Chagas disease, associate with vertebrate hosts in highly diverse ecotopes. It has been proposed that occupation of new microhabitats may trigger selection for distinct phenotypic variants in these blood-sucking bugs. Although understanding phenotypic variation is key to the study of adaptive evolution and central to phenotype-based taxonomy, the drivers of phenotypic change and diversity in triatomines remain poorly understood. Methods/results We combined a detailed phenotypic appraisal (including morphology and morphometrics) with mitochondrial cytb and nuclear ITS2 DNA sequence analyses to study Rhodnius ecuadoriensis populations from across the species’ range. We found three major, naked-eye phenotypic variants. Southern-Andean bugs primarily from vertebrate-nest microhabitats (Ecuador/Peru) are typical, light-colored, small bugs with short heads/wings. Northern-Andean bugs from wet-forest palms (Ecuador) are dark, large bugs with long ...
Memórias do Instituto Oswaldo Cruz
Reflections on Chagas disease in the Amazon This important update of the transmission profiles an... more Reflections on Chagas disease in the Amazon This important update of the transmission profiles and scenarios of Chagas disease (CD) highlights the enormous complexity and challenges that represent the prevention and control of parasitosis currently in the Americas and the planet. This global scenario is characterised by the acceleration generated by the fourth industrial revolution, the accelerated growth of the planetary population that puts pressure on nature, the climate change resulting from the prevailing industrial model, and the socioeconomic effects of the Coronaviurs disease (COVID-19) pandemic. The article highlights the operational purposes and prioritisation of efforts: The vectorial transmission of Trypanosoma cruzi is still active in rural areas of the Gran Chaco, extensive parts of the Andean Region, Central America, Mexico, in the southern USA. It is especially emphasised that the Amazon constitutes the next frontier of expansion of the massive transmission of T. cruzi and requires our professional and ethical commitment for its defense. The entomological situation in China and Vietnam constitutes an interesting inquiry that raises the possible introduction of T. cruzi in localities with competent, domiciled, and anthropophilic vectors. The presence of the parasite could turn them into active transmission foci, a remote but not impossible eventuality that has already occurred in other latitudes. (1) In this scenario, it is pertinent to restore Pavlovsky's (1939) (2) theory of natural foci, which from an ecological and geographical point of view, helps to understand the impact of human activities on the transformation of natural foci of some zoonoses. The transformation of natural foci explains the changes in the circulation of parasites in household and peri-household environments and their adaptation to new epidemiological patterns. (3) The theory of natural foci in the interpretation of Amazonian phenomena is valid for T. cruzi and agents of other diseases that circulate in natural foci such as leishmaniasis, yellow fever, rabies, leptospirosis, and several arboviruses whose natural foci are deterred by anthropic and predatory activities. (4) The Amazon, the largest biome on Earth, is subjected to an accelerated process of capitalist exploitation and extraction of natural resources, which threatens the balance of the last tropical rainforests and the populations that inhabit them as well as the survival of planetary life. It is foreseeable what will happen in the immediate future with the accelerated occupation of the Amazon, according to the underway national projects and even more after the arising socioeconomic needs aggravated by the pandemic crises that will increase pressure on the Amazonian resources to sustain the affected economies of the Amazonian States and their articulation with the world circuits. (5) According to the Amazonian Network of Georeferenced socio-environmental information (RAISG), (6) the Amazon is a territory of greater socio-environmental diversity in the process of accelerated change. It covers an area of 7.4 million km 2 comprising 12 macro basins and 158 sub-basins. The Amazon's river basin is the largest in the world, comprising 44% of the South American subcontinent. Representing more than half of the planet's tropical rainforest and is the world's largest tropical forest. The region represents between 4 and 6% of Earth's total surface area and around 25 to 40% of the Americas. The Amazon region covers 7,413,827 km², representing 54% of the total area of the eight OTCA Member Countries. (7) It is the largest and most complex forest on Earth, with at least 10,000 hectares of anthropogenic action, an area of extractivism, production of agro-industrial inputs, and non-renewable raw materials, both for nationals and international markets, compromising sustainable development and affects the conservation of vital spaces. Its 48 million inhabitants represent 11% of the Amazonian countries population (OTCA, 2021). There are 420 different indigenous tribes and populations, who speak 86 languages and 650 dialects. At least 60 indigenous populations live in total isolation. (7) An estimated 260,000 Amerindians who speak around 170 native languages live in the region. "Caboclos, ribeirinhos, seringueiros", and other traditional settlers generally settle in small communities along riverbanks, relying on subsistence agriculture, fishing, and forest extractivism. (8) In Pan-Amazonia, there is a ring of deforestation extending from Brazil to Bolivia, putting pressure on hydric resources, exploration of oil in the Andean Amazon (Colombia, Ecuador, and Peru), and an Amazonian mining ring. Deforestation, understood as the degradation or replacement of the original forest cover of the Amazon, has accelerated since the 1970s when countries such as Brazil, Ecuador, and Peru established a legal framework that encouraged colonisation and land occupation. Data from the Brazilian National Space Institute (INPE) reveal that in 1985 that 93.7% of the Amazonian coverage (3'841,932 km 2) was native, and 258,068 km 2 had been deforested. By 2018 the native coverage had been reduced to 82.7% accumulating 709,165 km 2 of deforested area. (5) In the last three years, deforestation has accelerated, especially in the State of Pará, Brazil. (9)
Revista Peruana de Medicina Experimental y Salud Pública, 2009
We present a short summary of the root causes that contribute to global warming and a host of evi... more We present a short summary of the root causes that contribute to global warming and a host of evidence of the reality that affects us; such as: raising the temperature of the earth, melting glaciers, rising ocean level, increases the frequency and intensity of weather events, all as a result of the unusual accumulation of greenhouse gases, as product of human activity. There are implications that directly or indirectly, the climate change has to health in particular for Andean countries; such as: disorders linked to the availability and quality of water and food, respiratory disease, vector-borne infections, cancer and pathologies chronic degenerative tables associated with climatic disasters and extreme temperatures. finally we review proposals and courses of action.
Revista de la Facultad de Ciencias Médicas (Quito), 2019
La Amazonia, conforme la Red Amazónica de Información Socio Ambiental Georreferenciada (RAISG), e... more La Amazonia, conforme la Red Amazónica de Información Socio Ambiental Georreferenciada (RAISG), es un territorio de altísima diversidad socioambiental en proceso de cambio acelerado.
The American Journal of Tropical Medicine and Hygiene, 2003
Serie Investigaciones Originales, 1988
Investigaciones Originales, 1988
Revista Panamericana de Salud Pública, 2001
Memórias do Instituto Oswaldo Cruz, 1999
Memórias do Instituto Oswaldo Cruz, 2001
Rev Inst Juan Cesar Garcia, Jul 1, 1993
Memórias do Instituto Oswaldo Cruz, 2001
PLOS Neglected Tropical Diseases, Mar 2, 2010
Background: Failure to detect a disease agent or vector where it actually occurs constitutes a se... more Background: Failure to detect a disease agent or vector where it actually occurs constitutes a serious drawback in epidemiology. In the pervasive situation where no sampling technique is perfect, the explicit analytical treatment of detection failure becomes a key step in the estimation of epidemiological parameters. We illustrate this approach with a study of Attalea palm tree infestation by Rhodnius spp. (Triatominae), the most important vectors of Chagas disease (CD) in northern South America. Methodology/Principal Findings: The probability of detecting triatomines in infested palms is estimated by repeatedly sampling each palm. This knowledge is used to derive an unbiased estimate of the biologically relevant probability of palm infestation. We combine maximum-likelihood analysis and information-theoretic model selection to test the relationships between environmental covariates and infestation of 298 Amazonian palm trees over three spatial scales: region within Amazonia, landscape, and individual palm. Palm infestation estimates are high (40-60%) across regions, and well above the observed infestation rate (24%). Detection probability is higher (,0.55 on average) in the richest-soil region than elsewhere (,0.08). Infestation estimates are similar in forest and rural areas, but lower in urban landscapes. Finally, individual palm covariates (accumulated organic matter and stem height) explain most of infestation rate variation. Conclusions/Significance: Individual palm attributes appear as key drivers of infestation, suggesting that CD surveillance must incorporate local-scale knowledge and that peridomestic palm tree management might help lower transmission risk. Vector populations are probably denser in rich-soil sub-regions, where CD prevalence tends to be higher; this suggests a target for research on broad-scale risk mapping. Landscape-scale effects indicate that palm triatomine populations can endure deforestation in rural areas, but become rarer in heavily disturbed urban settings. Our methodological approach has wide application in infectious disease research; by improving eco-epidemiological parameter estimation, it can also significantly strengthen vector surveillance-control strategies.
Parasites & Vectors, 2021
An amendment to this paper has been published and can be accessed via the original article.
Memórias do Instituto Oswaldo Cruz, 2002
Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Li... more Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Live-baited adhesive traps were tested in various ecosystems and different triatomine habitats (arboreal and terrestrial). The trials were always successful, with a rate of positive habitats generally over 20% and reaching 48.4% for palm trees of the Amazon basin. Eleven species of Triatominae belonging to the three genera of public health importance (Triatoma, Rhodnius and Panstrongylus) were captured. This trapping system provides an effective way to detect the presence of triatomines in terrestrial and arboreal silvatic habitats and represents a promising tool for ecological studies. Various lines of research are contemplated to improve the performance of this trapping system.
Memórias do Instituto Oswaldo Cruz, 2007
The risk that Chagas disease becomes established as a major endemic threat in Amazonia (the world... more The risk that Chagas disease becomes established as a major endemic threat in Amazonia (the world´s largest tropical biome, today inhabited by over 30 million people) relates to a complex set of interacting biological and social determinants. These include intense immigration from endemic areas (possibly introducing parasites and vectors), extensive landscape transformation with uncontrolled deforestation, and the great diversity of wild Trypanosoma cruzi reservoir hosts and vectors (25 species in nine genera), which maintain intense sylvatic transmission cycles. Invasion of houses by adventitious vectors (with infection rates > 60%) is common, and focal adaptation of native triatomines to artificial structures has been reported. Both acute (~ 500) and chronic cases of autochthonous human Chagas disease have been documented beyond doubt in the region. Continuous, low-intensity transmission seems to occur throughout the Amazon, and generates a hypoendemic pattern with seropositivity rates of ~ 1-3%. Discrete foci also exist in which transmission is more intense (e.g., in localized outbreaks probably linked to oral transmission) and prevalence rates higher. Early detection-treatment of acute cases is crucial for avoiding further dispersion of endemic transmission of Chagas disease in Amazonia, and will require the involvement of malaria control and primary health care systems. Comprehensive eco-epidemiological research, including prevalence surveys or the characterization of transmission dynamics in different ecological settings, is still needed. The International Initiative for Chagas Disesae Surveillance and Prevention in the Amazon provides the framework for building up the political and scientific cooperation networks required to confront the challenge of preventing Chagas disease in Amazonia.
Memórias do Instituto Oswaldo Cruz, 2002
Rhodnius ecuadoriensis infests peridomiciles and colonises houses in rural southern Ecuador. Six ... more Rhodnius ecuadoriensis infests peridomiciles and colonises houses in rural southern Ecuador. Six out of 84 dwellings (7%) surveyed in a rural village were infested (78 bugs/infested domicile; 279 bugs were collected in a single dwelling). Precipitin tests revealed R. ecuadoriensis fed on birds (65%), rodents (31%), marsupials (8%), and humans (15%)-mixed bloodmeals detected in 37.5% of individual samples. Trypanosoma cruzi from opossums and rodents may thus be introduced into the domestic cycle. Wasp parasitoidism was detected in 6.5% of 995 R. ecuadoriensis eggs (only in peridomestic habitats). Control strategies should integrate insecticide spraying (indoors and peridomestic), better management of poultry, and housing improvements. A possible inefficacy of Malathion is reported.
Parasites & Vectors, 2021
Background Triatomine bugs, the vectors of Chagas disease, associate with vertebrate hosts in hig... more Background Triatomine bugs, the vectors of Chagas disease, associate with vertebrate hosts in highly diverse ecotopes. It has been proposed that occupation of new microhabitats may trigger selection for distinct phenotypic variants in these blood-sucking bugs. Although understanding phenotypic variation is key to the study of adaptive evolution and central to phenotype-based taxonomy, the drivers of phenotypic change and diversity in triatomines remain poorly understood. Methods/results We combined a detailed phenotypic appraisal (including morphology and morphometrics) with mitochondrial cytb and nuclear ITS2 DNA sequence analyses to study Rhodnius ecuadoriensis populations from across the species’ range. We found three major, naked-eye phenotypic variants. Southern-Andean bugs primarily from vertebrate-nest microhabitats (Ecuador/Peru) are typical, light-colored, small bugs with short heads/wings. Northern-Andean bugs from wet-forest palms (Ecuador) are dark, large bugs with long ...
Memórias do Instituto Oswaldo Cruz
Reflections on Chagas disease in the Amazon This important update of the transmission profiles an... more Reflections on Chagas disease in the Amazon This important update of the transmission profiles and scenarios of Chagas disease (CD) highlights the enormous complexity and challenges that represent the prevention and control of parasitosis currently in the Americas and the planet. This global scenario is characterised by the acceleration generated by the fourth industrial revolution, the accelerated growth of the planetary population that puts pressure on nature, the climate change resulting from the prevailing industrial model, and the socioeconomic effects of the Coronaviurs disease (COVID-19) pandemic. The article highlights the operational purposes and prioritisation of efforts: The vectorial transmission of Trypanosoma cruzi is still active in rural areas of the Gran Chaco, extensive parts of the Andean Region, Central America, Mexico, in the southern USA. It is especially emphasised that the Amazon constitutes the next frontier of expansion of the massive transmission of T. cruzi and requires our professional and ethical commitment for its defense. The entomological situation in China and Vietnam constitutes an interesting inquiry that raises the possible introduction of T. cruzi in localities with competent, domiciled, and anthropophilic vectors. The presence of the parasite could turn them into active transmission foci, a remote but not impossible eventuality that has already occurred in other latitudes. (1) In this scenario, it is pertinent to restore Pavlovsky's (1939) (2) theory of natural foci, which from an ecological and geographical point of view, helps to understand the impact of human activities on the transformation of natural foci of some zoonoses. The transformation of natural foci explains the changes in the circulation of parasites in household and peri-household environments and their adaptation to new epidemiological patterns. (3) The theory of natural foci in the interpretation of Amazonian phenomena is valid for T. cruzi and agents of other diseases that circulate in natural foci such as leishmaniasis, yellow fever, rabies, leptospirosis, and several arboviruses whose natural foci are deterred by anthropic and predatory activities. (4) The Amazon, the largest biome on Earth, is subjected to an accelerated process of capitalist exploitation and extraction of natural resources, which threatens the balance of the last tropical rainforests and the populations that inhabit them as well as the survival of planetary life. It is foreseeable what will happen in the immediate future with the accelerated occupation of the Amazon, according to the underway national projects and even more after the arising socioeconomic needs aggravated by the pandemic crises that will increase pressure on the Amazonian resources to sustain the affected economies of the Amazonian States and their articulation with the world circuits. (5) According to the Amazonian Network of Georeferenced socio-environmental information (RAISG), (6) the Amazon is a territory of greater socio-environmental diversity in the process of accelerated change. It covers an area of 7.4 million km 2 comprising 12 macro basins and 158 sub-basins. The Amazon's river basin is the largest in the world, comprising 44% of the South American subcontinent. Representing more than half of the planet's tropical rainforest and is the world's largest tropical forest. The region represents between 4 and 6% of Earth's total surface area and around 25 to 40% of the Americas. The Amazon region covers 7,413,827 km², representing 54% of the total area of the eight OTCA Member Countries. (7) It is the largest and most complex forest on Earth, with at least 10,000 hectares of anthropogenic action, an area of extractivism, production of agro-industrial inputs, and non-renewable raw materials, both for nationals and international markets, compromising sustainable development and affects the conservation of vital spaces. Its 48 million inhabitants represent 11% of the Amazonian countries population (OTCA, 2021). There are 420 different indigenous tribes and populations, who speak 86 languages and 650 dialects. At least 60 indigenous populations live in total isolation. (7) An estimated 260,000 Amerindians who speak around 170 native languages live in the region. "Caboclos, ribeirinhos, seringueiros", and other traditional settlers generally settle in small communities along riverbanks, relying on subsistence agriculture, fishing, and forest extractivism. (8) In Pan-Amazonia, there is a ring of deforestation extending from Brazil to Bolivia, putting pressure on hydric resources, exploration of oil in the Andean Amazon (Colombia, Ecuador, and Peru), and an Amazonian mining ring. Deforestation, understood as the degradation or replacement of the original forest cover of the Amazon, has accelerated since the 1970s when countries such as Brazil, Ecuador, and Peru established a legal framework that encouraged colonisation and land occupation. Data from the Brazilian National Space Institute (INPE) reveal that in 1985 that 93.7% of the Amazonian coverage (3'841,932 km 2) was native, and 258,068 km 2 had been deforested. By 2018 the native coverage had been reduced to 82.7% accumulating 709,165 km 2 of deforested area. (5) In the last three years, deforestation has accelerated, especially in the State of Pará, Brazil. (9)
Revista Peruana de Medicina Experimental y Salud Pública, 2009
We present a short summary of the root causes that contribute to global warming and a host of evi... more We present a short summary of the root causes that contribute to global warming and a host of evidence of the reality that affects us; such as: raising the temperature of the earth, melting glaciers, rising ocean level, increases the frequency and intensity of weather events, all as a result of the unusual accumulation of greenhouse gases, as product of human activity. There are implications that directly or indirectly, the climate change has to health in particular for Andean countries; such as: disorders linked to the availability and quality of water and food, respiratory disease, vector-borne infections, cancer and pathologies chronic degenerative tables associated with climatic disasters and extreme temperatures. finally we review proposals and courses of action.
Revista de la Facultad de Ciencias Médicas (Quito), 2019
La Amazonia, conforme la Red Amazónica de Información Socio Ambiental Georreferenciada (RAISG), e... more La Amazonia, conforme la Red Amazónica de Información Socio Ambiental Georreferenciada (RAISG), es un territorio de altísima diversidad socioambiental en proceso de cambio acelerado.
The American Journal of Tropical Medicine and Hygiene, 2003
Serie Investigaciones Originales, 1988
Investigaciones Originales, 1988
Revista Panamericana de Salud Pública, 2001
Memórias do Instituto Oswaldo Cruz, 1999
Memórias do Instituto Oswaldo Cruz, 2001
Rev Inst Juan Cesar Garcia, Jul 1, 1993