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Navas ALA, Janko MM, Benítez FL, Narvaez M, Vasco LE, Kansara P, Zaitchik B, Pan WK, Mena CF. Impact of climate and land use/land cover changes on malaria incidence in the Ecuadorian Amazon. PLOS CLIMATE 2024; 3:e0000315. [PMID: 39027120 PMCID: PMC11257155 DOI: 10.1371/journal.pclm.0000315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Malaria transmission is influenced by climate and land use/land cover change (LULC). This study examines the impact of climate and LULC on malaria risk in the Ecuadorian Amazon. Weekly malaria surveillance data between 2008 and 2019 from Ecuador's Ministry of Public Health were combined with hydrometeorological and LULC data. Cross-correlation analyses identified time lags. Bayesian spatiotemporal models estimated annual LULC rates of change (ARC) by census area and assessed the effects on Plasmodium vivax and Plasmodium falciparum incidence. ARC for the five land cover classes (forest, agriculture, urban, shrub vegetation, water) ranged from -1 to 4% with agriculture increasing across areas. Forest and shrub vegetation ARC were significantly associated with both Plasmodium vivax and Plasmodium falciparum. Temperature and terrestrial water content showed consistent negative relationships with both species. Precipitation had varying effects on Plasmodium vivax (null) and Plasmodium falciparum (increase) incidence. Shrubs and forest expansion, increased temperature, and terrestrial water content reduced malaria incidence, while increased precipitation had varying effects. Relationships between malaria, LULC, and climate are complex, influencing risk profiles. These findings aid decision-making and guide further research in the region.
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Affiliation(s)
- Andrea L. Araujo Navas
- Universidad San Francisco de Quito USFQ, Institute of Geography, Quito, Pichincha, Ecuador
| | - Mark M. Janko
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
| | - Fátima L. Benítez
- Universidad San Francisco de Quito USFQ, Institute of Geography, Quito, Pichincha, Ecuador
- Department of Earth and Environmental Sciences, Faculty of Bioscience Engineering, Katholiek Universiteit van Leuven, Leuven, Belgium
| | - Manuel Narvaez
- Universidad San Francisco de Quito USFQ, Institute of Geography, Quito, Pichincha, Ecuador
| | - Luis E. Vasco
- Universidad San Francisco de Quito USFQ, Institute of Geography, Quito, Pichincha, Ecuador
| | - Prakrut Kansara
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Benjamin Zaitchik
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - William K. Pan
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
| | - Carlos F. Mena
- Universidad San Francisco de Quito USFQ, Institute of Geography, Quito, Pichincha, Ecuador
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2
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Fletcher IK, Gibb R, Lowe R, Jones KE. Differing taxonomic responses of mosquito vectors to anthropogenic land-use change in Latin America and the Caribbean. PLoS Negl Trop Dis 2023; 17:e0011450. [PMID: 37450491 PMCID: PMC10348580 DOI: 10.1371/journal.pntd.0011450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 06/08/2023] [Indexed: 07/18/2023] Open
Abstract
Anthropogenic land-use change, such as deforestation and urban development, can affect the emergence and re-emergence of mosquito-borne diseases, e.g., dengue and malaria, by creating more favourable vector habitats. There has been a limited assessment of how mosquito vectors respond to land-use changes, including differential species responses, and the dynamic nature of these responses. Improved understanding could help design effective disease control strategies. We compiled an extensive dataset of 10,244 Aedes and Anopheles mosquito abundance records across multiple land-use types at 632 sites in Latin America and the Caribbean. Using a Bayesian mixed effects modelling framework to account for between-study differences, we compared spatial differences in the abundance and species richness of mosquitoes across multiple land-use types, including agricultural and urban areas. Overall, we found that mosquito responses to anthropogenic land-use change were highly inconsistent, with pronounced responses observed at the genus- and species levels. There were strong declines in Aedes (-26%) and Anopheles (-35%) species richness in urban areas, however certain species such as Aedes aegypti, thrived in response to anthropogenic disturbance. When abundance records were coupled with remotely sensed forest loss data, we detected a strong positive response of dominant and secondary malaria vectors to recent deforestation. This highlights the importance of the temporal dynamics of land-use change in driving disease risk and the value of large synthetic datasets for understanding changing disease risk with environmental change.
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Affiliation(s)
- Isabel K. Fletcher
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Rory Gibb
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre for Biodiversity and Environment Research, University College London, London, United Kingdom
| | - Rachel Lowe
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Barcelona Supercomputing Center (BSC), Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Kate E. Jones
- Centre for Biodiversity and Environment Research, University College London, London, United Kingdom
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3
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Müller GA, de Mello CF, Bueno AS, de Alcantara Azevedo WT, Alencar J. Little noticed, but very important: The role of breeding sites formed by bamboos in maintaining the diversity of mosquitoes (Diptera: Culicidae) in the Atlantic Forest biome. PLoS One 2022; 17:e0273774. [PMID: 36067179 PMCID: PMC9447929 DOI: 10.1371/journal.pone.0273774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 08/12/2022] [Indexed: 11/18/2022] Open
Abstract
This study investigated the composition of mosquito species in different kinds of breeding sites in a tropical forest remnant of the Atlantic Forest and identified species of public health concern therein. Collections of immature forms of mosquitoes were carried out monthly at the Poço das Antas Biological Reserve in southeastern Brazil, between June 2014 and June 2015. Samples were collected from four types of breeding sites: bamboos, bromeliads, puddles, and a lake. A total of 1,182 specimens of mosquitoes belonging to 28 species and 13 genera were collected. Three species, Ad. squamipennis, An. neglectus, and Wy. arthrostigma represented 64.8% of the captured specimens. Only three species were found in more than one type of breeding site: Ps. ferox, An. triannulatus, and Tx. trichopygus. Two species of public health concern were found breeding in bamboo (Ae. aegypti and Ae. albopictus) and one in the lake (An. darlingi). Bamboo had the highest species richness, Shannon diversity, abundance of individuals and number of dominant species of all breeding sites. Similar Simpson diversity was obtained for bamboo and bromeliads, with higher values than those obtained for puddles and the lake. The significance of the four breeding sites, especially bamboos, is discussed in the context of controlling populations of sylvatic species of mosquitoes in Atlantic Forest areas.
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Affiliation(s)
- Gerson Azulim Müller
- Instituto Federal de Educação, Ciência e Tecnologia Farroupilha, Panambi, RS, Brazil
| | - Cecilia Ferreira de Mello
- Laboratório de Diptera, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil
- Programa de Pós-Graduação em Biologia Animal, Instituto de Biologia (UFRRJ), Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil
| | - Anderson S. Bueno
- Instituto Federal de Educação, Ciência e Tecnologia Farroupilha, Júlio de Castilhos, RS, Brazil
| | - Wellington Thadeu de Alcantara Azevedo
- Laboratório de Diptera, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil
- Programa de Pós-Graduação em Biologia Animal, Instituto de Biologia (UFRRJ), Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil
| | - Jeronimo Alencar
- Laboratório de Diptera, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil
- * E-mail:
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4
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de Almeida NCV, Louzada J, Neves MSAS, Carvalho TM, Castro-Alves J, Silva-do-Nascimento TF, Escalante AA, Oliveira-Ferreira J. Larval habitats, species composition and distribution of malaria vectors in regions with autochthonous and imported malaria in Roraima state, Brazil. Malar J 2022; 21:13. [PMID: 35027049 PMCID: PMC8759267 DOI: 10.1186/s12936-021-04033-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 12/18/2021] [Indexed: 11/10/2022] Open
Abstract
Background Malaria control requires local action. Assessing the vector diversity and abundance provides information on the local malariogenic potential or risk of transmission. This study aimed to determine the Anopheles species composition, habitats, seasonal occurrence, and distribution in areas with autochthonous and imported malaria cases in Roraima State. Methods A longitudinal study was conducted from January 2017 to October 2018, sampling larvae and adult mosquitoes in three municipalities of Roraima State: Boa Vista, Pacaraima and São João da Baliza. These areas have different risks of malaria importation. Four to six mosquito larval habitats were selected for larval sampling at each municipality, along with two additional sites for adult mosquito collection. All larval habitats were surveyed every two months using a standardized larval sampling methodology and MosqTent for adult mosquitoes. Results A total of 544 Anopheles larvae and 1488 adult mosquitoes were collected from the three municipalities studied. Although the species abundance differed between municipalities, the larvae of Anopheles albitarsis s.l., Anopheles nuneztovari s.l. and Anopheles triannulatus s.l. were collected from all larval habitats studied while Anopheles darlingi were collected only from Boa Vista and São João da Baliza. Adults of 11 species of the genus Anopheles were collected, and the predominant species in Boa Vista was An. albitarsis (88.2%) followed by An. darlingi (6.9%), while in São João da Baliza, An. darlingi (85.6%) was the most predominant species followed by An. albitarsis s.l. (9.2%). In contrast, the most abundant species in Pacaraima was Anopheles braziliensis (62%), followed by Anopheles peryassui (18%). Overall, the majority of anophelines exhibited greater extradomicile than peridomicile-biting preference. Anopheles darlingi was the only species found indoors. Variability in biting times was observed among species and municipalities. Conclusion This study revealed the composition of anopheline species and habitats in Boa Vista, Pacaraima and São João da Baliza. The species sampled differed in their behaviour with only An. darlingi being found indoors. Anopheles darlingi appeared to be the most important vector in São João da Baliza, an area of autochthonous malaria, and An. albitarsis s.l. and An. braziliensis in areas of low transmission, although there were increasing reports of imported malaria. Understanding the diversity of vector species and their ecology is essential for designing effective vector control strategies for these municipalities. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-04033-1.
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Affiliation(s)
| | - Jaime Louzada
- Universidade Federal de Roraima, Boa Vista, Roraima, Brasil
| | | | - Thiago M Carvalho
- Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil
| | - Júlio Castro-Alves
- Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil
| | | | - Ananias A Escalante
- Department of Biology/Institute for Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA, USA
| | - Joseli Oliveira-Ferreira
- Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil.
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5
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Rosas-Aguirre A, Moreno M, Moreno-Gutierrez D, Llanos-Cuentas A, Saavedra M, Contreras-Mancilla J, Barboza J, Alava F, Aguirre K, Carrasco G, Prussing C, Vinetz J, Conn JE, Speybroeck N, Gamboa D. Integrating Parasitological and Entomological Observations to Understand Malaria Transmission in Riverine Villages in the Peruvian Amazon. J Infect Dis 2021; 223:S99-S110. [PMID: 33906225 PMCID: PMC8079135 DOI: 10.1093/infdis/jiaa496] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Remote rural riverine villages account for most of the reported malaria cases in the Peruvian Amazon. As transmission decreases due to intensive standard control efforts, malaria strategies in these villages will need to be more focused and adapted to local epidemiology. METHODS By integrating parasitological, entomological, and environmental observations between January 2016 and June 2017, we provided an in-depth characterization of malaria transmission dynamics in 4 riverine villages of the Mazan district, Loreto department. RESULTS Despite variation across villages, malaria prevalence by polymerase chain reaction in March 2016 was high (>25% in 3 villages), caused by Plasmodium vivax mainly and composed of mostly submicroscopic infections. Housing without complete walls was the main malaria risk factor, while households close to forest edges were more commonly identified as spatial clusters of malaria prevalence. Villages in the basin of the Mazan River had a higher density of adult Anopheles darlingi mosquitoes, and retained higher prevalence and incidence rates compared to villages in the basin of the Napo River despite test-and-treat interventions. CONCLUSIONS High heterogeneity in malaria transmission was found across and within riverine villages, resulting from interactions between the microgeographic landscape driving diverse conditions for vector development, housing structure, and human behavior.
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Affiliation(s)
- Angel Rosas-Aguirre
- Research Institute of Health and Society, Université catholique de Louvain, Brussels, Belgium.,Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Marta Moreno
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Diamantina Moreno-Gutierrez
- Research Institute of Health and Society, Université catholique de Louvain, Brussels, Belgium.,Facultad de Medicina Humana, Universidad Nacional de la Amazonía Peruana, Loreto, Peru
| | - Alejandro Llanos-Cuentas
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.,Facultad de Salud Pública y Administración, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Marlon Saavedra
- International Centers of Excellence for Malaria Research-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Juan Contreras-Mancilla
- International Centers of Excellence for Malaria Research-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Jose Barboza
- International Centers of Excellence for Malaria Research-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Freddy Alava
- International Centers of Excellence for Malaria Research-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Kristhian Aguirre
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gabriel Carrasco
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.,International Centers of Excellence for Malaria Research-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.,Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Catharine Prussing
- School of Public Health, Department of Biomedical Sciences, State University of New York, Albany, New York, USA.,Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Joseph Vinetz
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.,International Centers of Excellence for Malaria Research-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.,Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA.,Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Jan E Conn
- School of Public Health, Department of Biomedical Sciences, State University of New York, Albany, New York, USA.,Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Niko Speybroeck
- Research Institute of Health and Society, Université catholique de Louvain, Brussels, Belgium
| | - Dionicia Gamboa
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.,International Centers of Excellence for Malaria Research-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.,Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
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6
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Rufalco-Moutinho P, Moura Kadri S, Peres Alonso D, Moreno M, Carrasco-Escobar G, Prussing C, Gamboa D, Vinetz JM, Mureb Sallum MA, Conn JE, Martins Ribolla PE. Ecology and larval population dynamics of the primary malaria vector Nyssorhynchus darlingi in a high transmission setting dominated by fish farming in western Amazonian Brazil. PLoS One 2021; 16:e0246215. [PMID: 33831004 PMCID: PMC8031405 DOI: 10.1371/journal.pone.0246215] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 03/23/2021] [Indexed: 11/21/2022] Open
Abstract
Vale do Rio Juruá in western Acre, Brazil, is a persistent malaria transmission hotspot partly due to fish farming development that was encouraged to improve local standards of living. Fish ponds can be productive breeding sites for Amazonian malaria vector species, including Nyssorhynchus darlingi, which, combined with high human density and mobility, add to the local malaria burden.This study reports entomological profile of immature and adult Ny. darlingi at three sites in Mâncio Lima, Acre, during the rainy and dry season (February to September, 2017). From 63 fishponds, 10,859 larvae were collected, including 5,512 first-instar Anophelinae larvae and 4,927 second, third and fourth-instars, of which 8.5% (n = 420) were Ny. darlingi. This species was most abundant in not-abandoned fishponds and in the presence of emerging aquatic vegetation. Seasonal analysis of immatures in urban landscapes found no significant difference in the numbers of Ny. darlingi, corresponding to equivalent population density during the rainy to dry transition period. However, in the rural landscape, significantly higher numbers of Ny. darlingi larvae were collected in August (IRR = 5.80, p = 0.037) and September (IRR = 6.62, p = 0.023) (dry season), compared to February (rainy season), suggesting important role of fishponds for vector population maintenance during the seasonal transition in this landscape type. Adult sampling detected mainly Ny. darlingi (~93%), with similar outdoor feeding behavior, but different abundance according to landscape profile: urban site 1 showed higher peaks of human biting rate in May (46 bites/person/hour), than February (4) and September (15), while rural site 3 shows similar HBR during the same sampling period (22, 24 and 21, respectively). This study contributes to a better understanding of the larvae biology of the main malaria vector in the Vale do Rio Juruá region and, ultimately will support vector control efforts.
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Affiliation(s)
- Paulo Rufalco-Moutinho
- Departamento de Bioestatística, Biologia Vegetal, Parasitologia e Zoologia, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
- * E-mail:
| | - Samir Moura Kadri
- Instituto de Biotecnologia, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
| | - Diego Peres Alonso
- Instituto de Biotecnologia, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
| | - Marta Moreno
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Gabriel Carrasco-Escobar
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Catharine Prussing
- Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, Albany, NY, United States of America
- New York State Department of Health, Wadsworth Center, Albany, NY, United States of America
| | - Dionicia Gamboa
- Facultad de Ciencias y Filosofía, Departamento de Ciencias Celulares y Moleculares, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicinal Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Joseph M. Vinetz
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicinal Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia, Lima, Peru
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT, United States of America
| | - Maria Anice Mureb Sallum
- Faculdade de Saúde Pública, Departamento de Epidemiologia, Universidade de São Paulo, São Paulo, Brazil
| | - Jan E. Conn
- Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, Albany, NY, United States of America
- New York State Department of Health, Wadsworth Center, Albany, NY, United States of America
| | - Paulo Eduardo Martins Ribolla
- Departamento de Bioestatística, Biologia Vegetal, Parasitologia e Zoologia, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
- Instituto de Biotecnologia, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
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7
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Laporta GZ, Ilacqua RC, Bergo ES, Chaves LSM, Rodovalho SR, Moresco GG, Figueira EAG, Massad E, de Oliveira TMP, Bickersmith SA, Conn JE, Sallum MAM. Malaria transmission in landscapes with varying deforestation levels and timelines in the Amazon: a longitudinal spatiotemporal study. Sci Rep 2021; 11:6477. [PMID: 33742028 PMCID: PMC7979798 DOI: 10.1038/s41598-021-85890-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 03/08/2021] [Indexed: 01/31/2023] Open
Abstract
The relationship between deforestation and malaria is a spatiotemporal process of variation in Plasmodium incidence in human-dominated Amazonian rural environments. The present study aimed to assess the underlying mechanisms of malarial exposure risk at a fine scale in 5-km2 sites across the Brazilian Amazon, using field-collected data with a longitudinal spatiotemporally structured approach. Anopheline mosquitoes were sampled from 80 sites to investigate the Plasmodium infection rate in mosquito communities and to estimate the malaria exposure risk in rural landscapes. The remaining amount of forest cover (accumulated deforestation) and the deforestation timeline were estimated in each site to represent the main parameters of both the frontier malaria hypothesis and an alternate scenario, the deforestation-malaria hypothesis, proposed herein. The maximum frequency of pathogenic sites occurred at the intermediate forest cover level (50% of accumulated deforestation) at two temporal deforestation peaks, e.g., 10 and 35 years after the beginning of the organization of a settlement. The incidence density of infected anophelines in sites where the original forest cover decreased by more than 50% in the first 25 years of settlement development was at least twice as high as the incidence density calculated for the other sites studied (adjusted incidence density ratio = 2.25; 95% CI, 1.38-3.68; p = 0.001). The results of this study support the frontier malaria as a unifying hypothesis for explaining malaria emergence and for designing specific control interventions in the Brazilian Amazon.
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Affiliation(s)
- Gabriel Z Laporta
- Setor de Pós-Graduação, Pesquisa e Inovação, Centro Universitário Saúde ABC (FMABC), Fundação ABC, Santo André, SP, Brazil.
| | - Roberto C Ilacqua
- Setor de Pós-Graduação, Pesquisa e Inovação, Centro Universitário Saúde ABC (FMABC), Fundação ABC, Santo André, SP, Brazil
| | - Eduardo S Bergo
- Superintendência de Controle de Endemias (SUCEN), Secretaria de Estado da Saúde de São Paulo, Araraquara, SP, Brazil
| | - Leonardo S M Chaves
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo (FSP-USP), São Paulo, SP, Brazil
| | - Sheila R Rodovalho
- Unidade Técnica de Doenças Transmissíveis e Análise de Situação em Saúde, Pan American Health Organization (PAHO/WHO), Brasília, DF, Brazil
| | - Gilberto G Moresco
- Coordenação-Geral de Vigilância de Zoonoses e Doenças de Transmissão Vetorial, Secretaria de Vigilância em Saúde, Ministério da Saúde (MS), Brasília, DF, Brazil
| | | | - Eduardo Massad
- Escola de Matemática Aplicada, Fundação Getúlio Vargas, Rio de Janeiro, RJ, Brazil
| | - Tatiane M P de Oliveira
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo (FSP-USP), São Paulo, SP, Brazil
| | - Sara A Bickersmith
- New York State Department of Health, The Wadsworth Center, Slingerlands, NY, USA
| | - Jan E Conn
- New York State Department of Health, The Wadsworth Center, Slingerlands, NY, USA
- Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY, USA
| | - Maria Anice M Sallum
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo (FSP-USP), São Paulo, SP, Brazil.
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8
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Chaves LSM, Bergo ES, Conn JE, Laporta GZ, Prist PR, Sallum MAM. Anthropogenic landscape decreases mosquito biodiversity and drives malaria vector proliferation in the Amazon rainforest. PLoS One 2021; 16:e0245087. [PMID: 33444320 PMCID: PMC7808592 DOI: 10.1371/journal.pone.0245087] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/21/2020] [Indexed: 01/25/2023] Open
Abstract
Inter-relationships among mosquito vectors, Plasmodium parasites, human ecology, and biotic and abiotic factors, drive malaria risk. Specifically, rural landscapes shaped by human activities have a great potential to increase the abundance of malaria vectors, putting many vulnerable people at risk. Understanding at which point the abundance of vectors increases in the landscape can help to design policies and interventions for effective and sustainable control. Using a dataset of adult female mosquitoes collected at 79 sites in malaria endemic areas in the Brazilian Amazon, this study aimed to (1) verify the association among forest cover percentage (PLAND), forest edge density (ED), and variation in mosquito diversity; and to (2) test the hypothesis of an association between landscape structure (i.e., PLAND and ED) and Nyssorhynchus darlingi (Root) dominance. Mosquito collections were performed employing human landing catch (HLC) (peridomestic habitat) and Shannon trap combined with HLC (forest fringe habitat). Nyssorhynchus darlingi abundance was used as the response variable in a generalized linear mixed model, and the Shannon diversity index (H') of the Culicidae community, PLAND, and the distance house-water drainage were used as predictors. Three ED categories were also used as random effects. A path analysis was used to understand comparative strengths of direct and indirect relationships among Amazon vegetation classes, Culicidae community, and Ny. darlingi abundance. Our results demonstrate that Ny. darlingi is negatively affected by H´ and PLAND of peridomestic habitat, and that increasing these variables (one-unit value at β0 = 768) leads to a decrease of 226 (P < 0.001) and 533 (P = 0.003) individuals, respectively. At the forest fringe, a similar result was found for H' (β1 = -218; P < 0.001) and PLAND (β1 = -337; P = 0.04). Anthropogenic changes in the Amazon vegetation classes decreased mosquito biodiversity, leading to increased Ny. darlingi abundance. Changes in landscape structure, specifically decreases in PLAND and increases in ED, led to Ny. darlingi becoming the dominant species, increasing malaria risk. Ecological mechanisms involving changes in landscape and mosquito species composition can help to understand changes in the epidemiology of malaria.
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Affiliation(s)
| | - Eduardo Sterlino Bergo
- Superintendência de Controle de Endemias, Secretaria de Estado da Saúde de São Paulo, Araraquara, SP, Brazil
| | - Jan E. Conn
- Wadsworth Center, New York State Department of Health, Albany, NY, United States of America
- Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY, United States of America
| | - Gabriel Zorello Laporta
- Setor de Pós-graduação, Pesquisa e Inovação, Centro Universitário Saúde ABC, Fundação ABC, Santo André, SP, Brazil
| | - Paula Ribeiro Prist
- Department of Ecology, Institute of Bioscience, University of São Paulo, São Paulo, SP, Brazil
| | - Maria Anice Mureb Sallum
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil
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9
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Nguyen M, Howes RE, Lucas TCD, Battle KE, Cameron E, Gibson HS, Rozier J, Keddie S, Collins E, Arambepola R, Kang SY, Hendriks C, Nandi A, Rumisha SF, Bhatt S, Mioramalala SA, Nambinisoa MA, Rakotomanana F, Gething PW, Weiss DJ. Mapping malaria seasonality in Madagascar using health facility data. BMC Med 2020; 18:26. [PMID: 32036785 PMCID: PMC7008536 DOI: 10.1186/s12916-019-1486-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 12/20/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Many malaria-endemic areas experience seasonal fluctuations in case incidence as Anopheles mosquito and Plasmodium parasite life cycles respond to changing environmental conditions. Identifying location-specific seasonality characteristics is useful for planning interventions. While most existing maps of malaria seasonality use fixed thresholds of rainfall, temperature, and/or vegetation indices to identify suitable transmission months, we construct a statistical modelling framework for characterising the seasonal patterns derived directly from monthly health facility data. METHODS With data from 2669 of the 3247 health facilities in Madagascar, a spatiotemporal regression model was used to estimate seasonal patterns across the island. In the absence of catchment population estimates or the ability to aggregate to the district level, this focused on the monthly proportions of total annual cases by health facility level. The model was informed by dynamic environmental covariates known to directly influence seasonal malaria trends. To identify operationally relevant characteristics such as the transmission start months and associated uncertainty measures, an algorithm was developed and applied to model realisations. A seasonality index was used to incorporate burden information from household prevalence surveys and summarise 'how seasonal' locations are relative to their surroundings. RESULTS Positive associations were detected between monthly case proportions and temporally lagged covariates of rainfall and temperature suitability. Consistent with the existing literature, model estimates indicate that while most parts of Madagascar experience peaks in malaria transmission near March-April, the eastern coast experiences an earlier peak around February. Transmission was estimated to start in southeast districts before southwest districts, suggesting that indoor residual spraying should be completed in the same order. In regions where the data suggested conflicting seasonal signals or two transmission seasons, estimates of seasonal features had larger deviations and therefore less certainty. CONCLUSIONS Monthly health facility data can be used to establish seasonal patterns in malaria burden and augment the information provided by household prevalence surveys. The proposed modelling framework allows for evidence-based and cohesive inferences on location-specific seasonal characteristics. As health surveillance systems continue to improve, it is hoped that more of such data will be available to improve our understanding and planning of intervention strategies.
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Affiliation(s)
- Michele Nguyen
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Rosalind E Howes
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Tim C D Lucas
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Katherine E Battle
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ewan Cameron
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Harry S Gibson
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jennifer Rozier
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Suzanne Keddie
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Emma Collins
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Rohan Arambepola
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Su Yun Kang
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Chantal Hendriks
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Anita Nandi
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Susan F Rumisha
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Samir Bhatt
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | | | | | | | - Peter W Gething
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Daniel J Weiss
- Malaria Atlas Project, Oxford Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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10
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Chu VM, Sallum MAM, Moore TE, Emerson KJ, Schlichting CD, Conn JE. Evidence for family-level variation of phenotypic traits in response to temperature of Brazilian Nyssorhynchus darlingi. Parasit Vectors 2020; 13:55. [PMID: 32041663 PMCID: PMC7011564 DOI: 10.1186/s13071-020-3924-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/01/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Nyssorhynchus darlingi (also known as Anopheles darlingi) is the primary malaria vector in the Amazon River Basin. In Brazil, analysis of single nucleotide polymorphisms (SNPs) previously detected three major population clusters, and a common garden experiment in a laboratory setting revealed significant population variation in life history traits. Increasing temperatures and local level variation can affect life history traits, i.e. adult longevity, that alter vectorial capacity with implications for malaria transmission in Ny. darlingi. METHODS We investigated the population structure of Ny. darlingi from 7 localities across Brazil utilizing SNPs and compared them to a comprehensive Ny. darlingi catalog. To test the effects of local level variation on life history traits, we reared F1 progeny from the 7 localities at three constant temperatures (20, 24 and 28 °C), measuring key life history traits (larval development, food-starved adult lifespan, adult size and daily survival). RESULTS Using nextRAD genotyping-by-sequencing, 93 of the field-collected Ny. darlingi were genotyped at 33,759 loci. Results revealed three populations (K = 3), congruent with major biomes (Amazonia, Cerrado and Mata Atlântica), with greater FST values between biomes than within. In the life history experiments, increasing temperature reduced larval development time, adult lifespan, and wing length in all localities. The variation of family responses for all traits within four localities of the Amazonia biome was significant (ANOVA, P < 0.05). Individual families within localities revealed a range of responses as temperature increased, for larval development, adult lifespan, wing length and survival time. CONCLUSIONS SNP analysis of several Brazilian localities provided results in support of a previous study wherein populations of Ny. darlingi were clustered by three major Brazilian biomes. Our laboratory results of temperature effects demonstrated that population variation in life history traits of Ny. darlingi exists at the local level, supporting previous research demonstrating the high plasticity of this species. Understanding this plasticity and inherent variation between families of Ny. darlingi at the local level should be considered when deploying intervention strategies and may improve the likelihood of successful malaria elimination in South America.
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Affiliation(s)
- Virginia M. Chu
- Department of Biomedical Sciences, School of Public Health, State University of New York at Albany, 150 New Scotland Avenue, Albany, NY USA
- Wadsworth Center, New York State Department of Health, New York State Route 5, Albany, NY USA
| | | | - Timothy E. Moore
- Department of Ecology and Evolutionary Biology, University of Connecticut, Hartford, CT USA
| | - Kevin J. Emerson
- Biology Department, St. Mary’s College of Maryland, St. Mary’s City, Maryland USA
| | - Carl D. Schlichting
- Department of Ecology and Evolutionary Biology, University of Connecticut, Hartford, CT USA
| | - Jan E. Conn
- Wadsworth Center, New York State Department of Health, New York State Route 5, Albany, NY USA
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11
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Tchoumbou MA, Mayi MPA, Malange ENF, Foncha FD, Kowo C, Fru-Cho J, Tchuinkam T, Awah-Ndukum J, Dorazio R, Nota Anong D, Cornel AJ, Sehgal RNM. Effect of deforestation on prevalence of avian haemosporidian parasites and mosquito abundance in a tropical rainforest of Cameroon. Int J Parasitol 2019; 50:63-73. [PMID: 31866311 DOI: 10.1016/j.ijpara.2019.10.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 10/09/2019] [Accepted: 10/11/2019] [Indexed: 10/25/2022]
Abstract
Habitat change caused by deforestation can modify the interactions of many biotic and abiotic factors, and in turn influence patterns of diseases in wild birds. Whether deforestation directly or indirectly affects the prevalence of avian haemosporidian parasites through their hosts and/or vectors is still not well understood. We sampled understory bird communities (insectivorous, frugivorous, granivorous and nectarivorous birds) and mosquitoes in three habitats showing a gradient of deforestation (pristine forest, fragmented forest, and young palm oil plantation), to assess the effects of habitat changes on avian haemosporidian (Plasmodium and Haemoproteus) prevalence and its relationship to bird feeding guilds and mosquito abundance. Blood samples of 845 individual birds belonging to 85 species and 27 families were collected in the three habitat types and screened using microscopy and PCR. Plasmodium infections were detected in 136 individuals (16.09%) and varied significantly among habitat types while Haemoproteus infections were detected in 98 individuals (11.60%) and did not vary significantly among habitat types. However, the prevalence of Plasmodium and Haemoproteus in bird feeding groups varied significantly among habitats. Nectarivorous and granivorous birds had the highest Plasmodium and Haemoproteus prevalence, respectively. The abundance of mosquitoes varied significantly among habitat types and the prevalence of Plasmodium significantly and positively correlated with mosquito abundance in fragmented forest. This study highlights the importance of host and mosquito determinants in the transmission dynamics of avian Plasmodium and Haemoproteus infections following habitat changes. Selective logging favored an increase in the prevalence of Plasmodium in insectivores, the prevalence of Haemoproteus in nectarivores and the abundance of female mosquitoes while, the establishment of the palm oil plantation favored an increase in the prevalence of Plasmodium in granivores and Haemoproteus in nectarivores. Species feeding behavior is also an important determinant to consider for a better understanding of patterns of parasite infections in a changing environment.
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Affiliation(s)
- Mélanie Adèle Tchoumbou
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, University of Dschang, P.O. Box 067, Dschang, Cameroon.
| | - Marie Paul Audrey Mayi
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, University of Dschang, P.O. Box 067, Dschang, Cameroon
| | - Elikwo N F Malange
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Forfuet David Foncha
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Cyril Kowo
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Jerome Fru-Cho
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Timoléon Tchuinkam
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, University of Dschang, P.O. Box 067, Dschang, Cameroon
| | - Julius Awah-Ndukum
- Department of Animal Science, University of Dschang, P.O. Box 222, Dschang, Cameroon
| | - Robert Dorazio
- Department of Biology, San Francisco State University. 1600 Holloway Ave, San Francisco, CA 94132, USA
| | - Damian Nota Anong
- Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Anthony John Cornel
- Department of Entomology and Nematology, Mosquito Control Research Laboratory, University of California at Davis.9240 South Riverbend Ave, Parlier, CA 93648, USA
| | - Ravinder N M Sehgal
- Department of Biology, San Francisco State University. 1600 Holloway Ave, San Francisco, CA 94132, USA
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12
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Davidson G, Chua TH, Cook A, Speldewinde P, Weinstein P. The Role of Ecological Linkage Mechanisms in Plasmodium knowlesi Transmission and Spread. ECOHEALTH 2019; 16:594-610. [PMID: 30675676 DOI: 10.1007/s10393-019-01395-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 11/10/2018] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
Defining the linkages between landscape change, disease ecology and human health is essential to explain and predict the emergence of Plasmodium knowlesi malaria, a zoonotic parasite residing in Southeast Asian macaques, and transmitted by species of Anopheles mosquitos. Changing patterns of land use throughout Southeast Asia, particularly deforestation, are suggested to be the primary drivers behind the recent spread of this zoonotic parasite in humans. Local ecological changes at the landscape scale appear to be increasing the risk of disease in humans by altering the dynamics of transmission between the parasite and its primary hosts. This paper will focus on the emergence of P. knowlesi in humans in Malaysian Borneo and the ecological linkage mechanisms suggested to be playing an important role.
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Affiliation(s)
- Gael Davidson
- CENRM and School of Population and Global Health, University of Western Australia, Perth, Australia
| | - Tock H Chua
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia.
| | - Angus Cook
- School of Population and Global Health, University of Western Australia, Perth, Australia
| | | | - Philip Weinstein
- School of Biological Sciences, University of Adelaide, Adelaide, Australia
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13
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Solano-Villarreal E, Valdivia W, Pearcy M, Linard C, Pasapera-Gonzales J, Moreno-Gutierrez D, Lejeune P, Llanos-Cuentas A, Speybroeck N, Hayette MP, Rosas-Aguirre A. Malaria risk assessment and mapping using satellite imagery and boosted regression trees in the Peruvian Amazon. Sci Rep 2019; 9:15173. [PMID: 31645604 PMCID: PMC6811674 DOI: 10.1038/s41598-019-51564-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/02/2019] [Indexed: 12/02/2022] Open
Abstract
This is the first study to assess the risk of co-endemic Plasmodium vivax and Plasmodium falciparum transmission in the Peruvian Amazon using boosted regression tree (BRT) models based on social and environmental predictors derived from satellite imagery and data. Yearly cross-validated BRT models were created to discriminate high-risk (annual parasite index API > 10 cases/1000 people) and very-high-risk for malaria (API > 50 cases/1000 people) in 2766 georeferenced villages of Loreto department, between 2010-2017 as other parts in the article (graphs, tables, and texts). Predictors were cumulative annual rainfall, forest coverage, annual forest loss, annual mean land surface temperature, normalized difference vegetation index (NDVI), normalized difference water index (NDWI), shortest distance to rivers, time to populated villages, and population density. BRT models built with predictor data of a given year efficiently discriminated the malaria risk for that year in villages (area under the ROC curve (AUC) > 0.80), and most models also effectively predicted malaria risk in the following year. Cumulative rainfall, population density and time to populated villages were consistently the top three predictors for both P. vivax and P. falciparum incidence. Maps created using the BRT models characterize the spatial distribution of the malaria incidence in Loreto and should contribute to malaria-related decision making in the area.
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Affiliation(s)
- Elisa Solano-Villarreal
- Université de Liège, 4000, Liège, Belgium.
- Research Institute of Health and Society (IRSS), Université catholique de Louvain, 1200, Brussels, Belgium.
- Institute of Tropical Medicine Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, 15102, Peru.
| | - Walter Valdivia
- Ministry of Development and Social Inclusion, Lima, 15047, Peru
| | - Morgan Pearcy
- Research Institute of Health and Society (IRSS), Université catholique de Louvain, 1200, Brussels, Belgium
| | - Catherine Linard
- Namur Research Institute for Life Sciences (Narilis), Université de Namur, 5000, Namur, Belgium
- Institute of Life-Earth-Environment (ILEE), 5000, Namur, Belgium
| | | | - Diamantina Moreno-Gutierrez
- Research Institute of Health and Society (IRSS), Université catholique de Louvain, 1200, Brussels, Belgium
- University of Antwerp, 2000, Antwerp, Belgium
- Faculty of Human Medicine, Universidad Nacional de la Amazonía Peruana, Loreto, 160, Peru
| | | | - Alejandro Llanos-Cuentas
- Institute of Tropical Medicine Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, 15102, Peru
| | - Niko Speybroeck
- Research Institute of Health and Society (IRSS), Université catholique de Louvain, 1200, Brussels, Belgium
| | | | - Angel Rosas-Aguirre
- Research Institute of Health and Society (IRSS), Université catholique de Louvain, 1200, Brussels, Belgium
- Institute of Tropical Medicine Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, 15102, Peru
- Fonds de la Recherche Scientifique (FNRS), 1000, Brussels, Belgium
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14
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de Oliveira Padilha MA, de Oliveira Melo J, Romano G, de Lima MVM, Alonso WJ, Sallum MAM, Laporta GZ. Comparison of malaria incidence rates and socioeconomic-environmental factors between the states of Acre and Rondônia: a spatio-temporal modelling study. Malar J 2019; 18:306. [PMID: 31484519 PMCID: PMC6727495 DOI: 10.1186/s12936-019-2938-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 08/27/2019] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Plasmodium falciparum malaria is a threat to public health, but Plasmodium vivax malaria is most prevalent in Latin America, where the incidence rate has been increasing since 2016, particularly in Venezuela and Brazil. The Brazilian Amazon reported 193,000 cases in 2017, which were mostly confirmed as P. vivax (~ 90%). Herein, the relationships among malaria incidence rates and the proportion of accumulated deforestation were contrasted using data from the states of Acre and Rondônia in the south-western Brazilian Amazon. The main purpose is to test the hypothesis that the observed difference in incidence rates is associated with the proportion of accumulated deforestation. METHODS An ecological study using spatial and temporal models for mapping and modelling malaria risk was performed. The municipalities of Acre and Rondônia were the spatial units of analysis, whereas month and year were the temporal units. The number of reported malaria cases from 2009 until 2015 were used to calculate the incidence rate per 1000 people at risk. Accumulated deforestation was calculated using publicly available satellite images. Geographically weighted regression was applied to provide a local model of the spatial heterogeneity of incidence rates. Time-series dynamic regression was applied to test the correlation of incidence rates and accumulated deforestation, adjusted by climate and socioeconomic factors. RESULTS The malaria incidence rate declined in Rondônia but remained stable in Acre. There was a high and positive correlation between the decline in malaria and higher proportions of accumulated deforestation in Rondônia. Geographically weighted regression showed a complex relationship. As deforestation increased, malaria incidence also increased in Acre, while as deforestation increased, malaria incidence decreased in Rondônia. Time-series dynamic regression showed a positive association between malaria incidence and precipitation and accumulated deforestation, whereas the association was negative with the human development index in the westernmost areas of Acre. CONCLUSION Landscape modification caused by accumulated deforestation is an important driver of malaria incidence in the Brazilian Amazon. However, this relationship is not linearly correlated because it depends on the overall proportion of the land covered by forest. For regions that are partially degraded, forest cover becomes a less representative component in the landscape, causing the abovementioned non-linear relationship. In such a scenario, accumulated deforestation can lead to a decline in malaria incidence.
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Affiliation(s)
| | - Janille de Oliveira Melo
- Setor de Pós-graduação, Pesquisa e Inovação, Centro Universitário Saúde ABC, Fundação do ABC, Santo André, SP, Brazil
| | - Guilherme Romano
- Setor de Pós-graduação, Pesquisa e Inovação, Centro Universitário Saúde ABC, Fundação do ABC, Santo André, SP, Brazil
| | - Marcos Vinicius Malveira de Lima
- Setor de Pós-graduação, Pesquisa e Inovação, Centro Universitário Saúde ABC, Fundação do ABC, Santo André, SP, Brazil
- Gerência Estadual de Controle de Endemias, Rio Branco, AC, Brazil
| | | | - Maria Anice Mureb Sallum
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil.
| | - Gabriel Zorello Laporta
- Setor de Pós-graduação, Pesquisa e Inovação, Centro Universitário Saúde ABC, Fundação do ABC, Santo André, SP, Brazil.
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL, USA.
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15
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Souza PF, Xavier DR, Suarez Mutis MC, da Mota JC, Peiter PC, de Matos VP, Magalhães MDAFM, Barcellos C. Spatial spread of malaria and economic frontier expansion in the Brazilian Amazon. PLoS One 2019; 14:e0217615. [PMID: 31211772 PMCID: PMC6581252 DOI: 10.1371/journal.pone.0217615] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/15/2019] [Indexed: 12/01/2022] Open
Abstract
The temporal and spatial evolution of malaria was described for the postfrontier phase of the Brazilian Amazon in 2003–2013. The current ecological study aimed to understand the relationship between spatial population mobility and the distribution of malaria cases. The study identified epidemiologically relevant areas using regional statistical modeling and spatial analyses that considered differential infections and types of work activities. Annual parasite incidence (API) in the region was highest in hotspots along the Amazon River and in the south and west settlement zone of Hiléia, with concentrations in environmental protection areas and açaí and Brazil nut extraction areas. The dispersal force decreased in the Central Amazon due to rapid urbanization and improved socioeconomic conditions for workers in consolidated settlement areas. The study characterized the spatial patterns of disease transmission according to the economic activity and regionalization of geographic areas, confirming that the incidence of infection by work activity and labor flow is linked to extractive activities and agricultural settlements.
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Affiliation(s)
- Patrícia Feitosa Souza
- Oswaldo Cruz Foundation, Institute of Scientific and Technological Information and Communication in Health, Health Information Laboratory, GIS Laboratory, Rio de Janeiro, Brazil
- * E-mail:
| | - Diego Ricardo Xavier
- Oswaldo Cruz Foundation, Institute of Scientific and Technological Information and Communication in Health, Health Information Laboratory, GIS Laboratory, Rio de Janeiro, Brazil
| | | | - Jurema Corrêa da Mota
- Oswaldo Cruz Foundation, Institute of Scientific and Technological Information and Communication in Health, Health Information Laboratory, GIS Laboratory, Rio de Janeiro, Brazil
| | | | - Vanderlei Pascoal de Matos
- Oswaldo Cruz Foundation, Institute of Scientific and Technological Information and Communication in Health, Health Information Laboratory, GIS Laboratory, Rio de Janeiro, Brazil
| | - Mônica de Avelar Figueiredo Mafra Magalhães
- Oswaldo Cruz Foundation, Institute of Scientific and Technological Information and Communication in Health, Health Information Laboratory, GIS Laboratory, Rio de Janeiro, Brazil
| | - Christovam Barcellos
- Oswaldo Cruz Foundation, Institute of Scientific and Technological Information and Communication in Health, Health Information Laboratory, GIS Laboratory, Rio de Janeiro, Brazil
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16
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Prussing C, Saavedra MP, Bickersmith SA, Alava F, Guzmán M, Manrique E, Carrasco-Escobar G, Moreno M, Gamboa D, Vinetz JM, Conn JE. Malaria vector species in Amazonian Peru co-occur in larval habitats but have distinct larval microbial communities. PLoS Negl Trop Dis 2019; 13:e0007412. [PMID: 31091236 PMCID: PMC6538195 DOI: 10.1371/journal.pntd.0007412] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 05/28/2019] [Accepted: 04/24/2019] [Indexed: 12/19/2022] Open
Abstract
In Amazonian Peru, the primary malaria vector, Nyssorhynchus darlingi (formerly Anopheles darlingi), is difficult to target using standard vector control methods because it mainly feeds and rests outdoors. Larval source management could be a useful supplementary intervention, but to determine its feasibility, more detailed studies on the larval ecology of Ny. darlingi are essential. We conducted a multi-level study of the larval ecology of Anophelinae mosquitoes in the peri-Iquitos region of Amazonian Peru, examining the environmental characteristics of the larval habitats of four species, comparing the larval microbiota among species and habitats, and placing Ny. darlingi larval habitats in the context of spatial heterogeneity in human malaria transmission. We collected Ny. darlingi, Nyssorhynchus rangeli (formerly Anopheles rangeli), Nyssorhynchus triannulatus s.l. (formerly Anopheles triannulatus s.l.), and Nyssorhynchus sp. nr. konderi (formerly Anopheles sp. nr. konderi) from natural and artificial water bodies throughout the rainy and dry seasons. We found that, consistent with previous studies in this region and in Brazil, the presence of Ny. darlingi was significantly associated with water bodies in landscapes with more recent deforestation and lower light intensity. Nyssorhynchus darlingi presence was also significantly associated with a lower vegetation index, other Anophelinae species, and emergent vegetation. Though they were collected in the same water bodies, the microbial communities of Ny. darlingi larvae were distinct from those of Ny. rangeli and Ny. triannulatus s.l., providing evidence either for a species-specific larval microbiome or for segregation of these species in distinct microhabitats within each water body. We demonstrated that houses with more reported malaria cases were located closer to Ny. darlingi larval habitats; thus, targeted control of these sites could help ameliorate malaria risk. The co-occurrence of Ny. darlingi larvae in water bodies with other putative malaria vectors increases the potential impact of larval source management in this region.
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Affiliation(s)
- Catharine Prussing
- Department of Biomedical Sciences, School of Public Health, University at Albany–State University of New York, Albany, NY, United States of America
| | - Marlon P. Saavedra
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Sara A. Bickersmith
- Wadsworth Center, New York State Department of Health, Albany, NY, United States of America
| | | | - Mitchel Guzmán
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Edgar Manrique
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gabriel Carrasco-Escobar
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
- Facultad de Salud Pública, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Marta Moreno
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Dionicia Gamboa
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicina Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Joseph M. Vinetz
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Jan E. Conn
- Department of Biomedical Sciences, School of Public Health, University at Albany–State University of New York, Albany, NY, United States of America
- Wadsworth Center, New York State Department of Health, Albany, NY, United States of America
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Sallum MAM, Conn JE, Bergo ES, Laporta GZ, Chaves LSM, Bickersmith SA, de Oliveira TMP, Figueira EAG, Moresco G, Olívêr L, Struchiner CJ, Yakob L, Massad E. Vector competence, vectorial capacity of Nyssorhynchus darlingi and the basic reproduction number of Plasmodium vivax in agricultural settlements in the Amazonian Region of Brazil. Malar J 2019; 18:117. [PMID: 30947726 PMCID: PMC6449965 DOI: 10.1186/s12936-019-2753-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/28/2019] [Indexed: 11/10/2022] Open
Abstract
Background Brazilian malaria control programmes successfully reduced the incidence and mortality rates from 2005 to 2016. Since 2017, increased malaria has been reported across the Amazon. Few field studies focus on the primary malaria vector in high to moderate endemic areas, Nyssorhynchus darlingi, as the key entomological component of malaria risk, and on the metrics of Plasmodium vivax propagation in Amazonian rural communities. Methods Human landing catch collections were carried out in 36 houses of 26 communities in five municipalities in the Brazilian states of Acre, Amazonas and Rondônia states, with API (> 30). In addition, data on the number of locally acquired symptomatic infections were employed in mathematical modelling analyses carried out to determine Ny. darlingi vector competence and vectorial capacity to P. vivax; and to calculate the basic reproduction number for P. vivax. Results Entomological indices and malaria metrics ranged among localities: prevalence of P. vivax infection in Ny. darlingi, from 0.243% in Mâncio Lima, Acre to 3.96% in Machadinho D’Oeste, Rondônia; daily human-biting rate per person from 23 ± 1.18 in Cruzeiro do Sul, Acre, to 66 ± 2.41 in Lábrea, Amazonas; vector competence from 0.00456 in São Gabriel da Cachoeira, Amazonas to 0.04764 in Mâncio Lima, Acre; vectorial capacity from 0.0836 in Mâncio Lima, to 1.5 in Machadinho D’Oeste. The estimated R0 for P. vivax (PvR0) was 3.3 in Mâncio Lima, 7.0 in Lábrea, 16.8 in Cruzeiro do Sul, 55.5 in São Gabriel da Cachoeira, and 58.7 in Machadinho D’Oeste. Correlation between P. vivax prevalence in Ny. darlingi and vector competence was non-linear whereas association between prevalence of P. vivax in mosquitoes, vectorial capacity and R0 was linear and positive. Conclusions In spite of low vector competence of Ny. darlingi to P. vivax, parasite propagation in the human population is enhanced by the high human-biting rate, and relatively high vectorial capacity. The high PvR0 values suggest hyperendemicity in Machadinho D’Oeste and São Gabriel da Cachoeira at levels similar to those found for P. falciparum in sub-Saharan Africa regions. Mass screening for parasite reservoirs, effective anti-malarial drugs and vector control interventions will be necessary to shrinking transmission in Amazonian rural communities, Brazil. Electronic supplementary material The online version of this article (10.1186/s12936-019-2753-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maria Anice M Sallum
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil.
| | - Jan E Conn
- Wadsworth Center, New York State Department of Health, Albany, NY, USA.,Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY, USA
| | - Eduardo S Bergo
- Superintendência de Controle de Endemias, Secretaria de Estado da Saúde de São Paulo, Araraquara, SP, Brazil
| | - Gabriel Z Laporta
- Setor de Pós-graduação, Pesquisa e Inovação, Faculdade de Medicina do ABC, Santo André, SP, Brazil
| | - Leonardo S M Chaves
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | - Tatiane M P de Oliveira
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | - Gilberto Moresco
- Secretaria de Vigilância em Saúde, Departamento de Vigilância das Doenças Transmissíveis, Ministério da Saúde, Brasília, DF, Brazil
| | - Lêuda Olívêr
- Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Claudio J Struchiner
- Departamento de Doenças Endêmicas Samuel Pessoa, Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Eduardo Massad
- Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.,Escola de Matemática Aplicada, Fundação Getúlio Vargas, Rio de Janeiro, RJ, Brazil
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Ilacqua RC, Chaves LSM, Bergo ES, Conn JE, Sallum MAM, Laporta GZ. A method for estimating the deforestation timeline in rural settlements in a scenario of malaria transmission in frontier expansion in the Amazon Region. Mem Inst Oswaldo Cruz 2018; 113:e170522. [PMID: 30043836 PMCID: PMC6055538 DOI: 10.1590/0074-02760170522] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/29/2018] [Indexed: 01/06/2023] Open
Abstract
The Malaria Frontier Hypothesis (MFH) is the current model for predicting malaria emergence in the Brazilian Amazon. It has two important dimensions, 'settlement time' and 'malaria incidence', and its prediction are: malaria incidence peaks five years after the initiation of human settlement and declines towards zero after an estimated 10 years. Although MFH is currently accepted, it has been challenged recently. Herein, we described a novel method for estimating settlement timeline by using remote sensing technology integrated in an open-software geographic information system. Surprisingly, we found that of the majority of the rural settlements with high malaria incidence are more than 10 years old.
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Affiliation(s)
- Roberto Cardoso Ilacqua
- Faculdade de Medicina do ABC, Setor de Pós-Graduação, Pesquisa e Inovação, Santo André, SP, Brasil
| | | | - Eduardo Sterlino Bergo
- Secretaria de Estado da Saúde de São Paulo, Superintendência de Controle de Endemias, Araraquara, SP, Brasil
| | - Jan E Conn
- The Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA.,University at Albany, State University of New York, Department of Biomedical Sciences, School of Public Health, Albany, NY, USA
| | - Maria Anice Mubeb Sallum
- Universidade de São Paulo, Faculdade de Saúde Pública, Departamento de Epidemiologia, São Paulo, SP, Brasil
| | - Gabriel Zorello Laporta
- Faculdade de Medicina do ABC, Setor de Pós-Graduação, Pesquisa e Inovação, Santo André, SP, Brasil.,Universidade Federal do ABC, Centro de Engenharia, Modelagem e Ciências Sociais Aplicadas, Santo André, SP, Brasil
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Chaves LSM, Conn JE, López RVM, Sallum MAM. Abundance of impacted forest patches less than 5 km 2 is a key driver of the incidence of malaria in Amazonian Brazil. Sci Rep 2018; 8:7077. [PMID: 29728637 PMCID: PMC5935754 DOI: 10.1038/s41598-018-25344-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 04/19/2018] [Indexed: 12/20/2022] Open
Abstract
The precise role that deforestation for agricultural settlements and commercial forest products plays in promoting or inhibiting malaria incidence in Amazonian Brazil is controversial. Using publically available databases, we analyzed temporal malaria incidence (2009–2015) in municipalities of nine Amazonian states in relation to ecologically defined variables: (i) deforestation (rate of forest clearing over time); (ii) degraded forest (degree of human disturbance and openness of forest canopy for logging) and (iii) impacted forest (sum of deforested and degraded forest patches). We found that areas affected by one kilometer square of deforestation produced 27 new malaria cases (r² = 0.78; F1,10 = 35.81; P < 0.001). Unexpectedly, we found both a highly significant positive correlation between number of impacted forest patches less than 5 km2 and malaria cases, and that these patch sizes accounted for greater than ~95% of all patches in the study area. There was a significantly negative correlation between extraction forestry economic indices and malaria cases. Our results emphasize not only that deforestation promotes malaria incidence, but also that it directly or indirectly results in a low Human Development Index, and favors environmental conditions that promote malaria vector proliferation.
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Affiliation(s)
| | - Jan E Conn
- Department of Biomedical Sciences, School of Public Health, University at Albany (State University of New York), Albany, NY, USA.,Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | | | - Maria Anice Mureb Sallum
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil
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20
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Catry T, Li Z, Roux E, Herbreteau V, Gurgel H, Mangeas M, Seyler F, Dessay N. Wetlands and Malaria in the Amazon: Guidelines for the Use of Synthetic Aperture Radar Remote-Sensing. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:E468. [PMID: 29518988 PMCID: PMC5877013 DOI: 10.3390/ijerph15030468] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 11/16/2022]
Abstract
The prevention and control of mosquito-borne diseases, such as malaria, are important health issues in tropical areas. Malaria transmission is a multi-scale process strongly controlled by environmental factors, and the use of remote-sensing data is suitable for the characterization of its spatial and temporal dynamics. Synthetic aperture radar (SAR) is well-adapted to tropical areas, since it is capable of imaging independent of light and weather conditions. In this study, we highlight the contribution of SAR sensors in the assessment of the relationship between vectors, malaria and the environment in the Amazon region. More specifically, we focus on the SAR-based characterization of potential breeding sites of mosquito larvae, such as man-made water collections and natural wetlands, providing guidelines for the use of SAR capabilities and techniques in order to optimize vector control and malaria surveillance. In light of these guidelines, we propose a framework for the production of spatialized indicators and malaria risk maps based on the combination of SAR, entomological and epidemiological data to support malaria risk prevention and control actions in the field.
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Affiliation(s)
- Thibault Catry
- ESPACE-DEV, UMR 228 IRD/UM/UR/UG/UA, Institut de Recherche pour le Développement (IRD), 34093 Montpellier, France.
| | - Zhichao Li
- Ministry of Education, Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing 100084, China.
| | - Emmanuel Roux
- ESPACE-DEV, UMR 228 IRD/UM/UR/UG/UA, Institut de Recherche pour le Développement (IRD), 34093 Montpellier, France.
| | - Vincent Herbreteau
- ESPACE-DEV, UMR 228 IRD/UM/UR/UG/UA, Institut de Recherche pour le Développement (IRD), 34093 Montpellier, France.
- ESPACE-DEV, UMR 228 IRD/UM/UR/UG/UA, Institut de Recherche pour le Développement (IRD), SEAS-OI, 97410 La Réunion, France.
| | - Helen Gurgel
- Department of Geography (GEA), University of Brasília (UnB), Brasília 70910-900, Brazil.
| | - Morgan Mangeas
- ESPACE-DEV, UMR 228 IRD/UM/UR/UG/UA, Institut de Recherche pour le Développement (IRD), 98848 Nouvelle-Calédonie, France.
| | - Frédérique Seyler
- ESPACE-DEV, UMR 228 IRD/UM/UR/UG/UA, Institut de Recherche pour le Développement (IRD), 34093 Montpellier, France.
| | - Nadine Dessay
- ESPACE-DEV, UMR 228 IRD/UM/UR/UG/UA, Institut de Recherche pour le Développement (IRD), 34093 Montpellier, France.
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Tucker Lima JM, Vittor A, Rifai S, Valle D. Does deforestation promote or inhibit malaria transmission in the Amazon? A systematic literature review and critical appraisal of current evidence. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0125. [PMID: 28438914 PMCID: PMC5413873 DOI: 10.1098/rstb.2016.0125] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2016] [Indexed: 12/22/2022] Open
Abstract
Considerable interest in the relationship between biodiversity and disease has recently captured the attention of the research community, with important public policy implications. In particular, malaria in the Amazon region is often cited as an example of how forest conservation can improve public health outcomes. However, despite a growing body of literature and an increased understanding of the relationship between malaria and land use / land cover change (LULC) in Amazonia, contradictions have emerged. While some studies report that deforestation increases malaria risk, others claim the opposite. Assessing malaria risk requires examination of dynamic processes among three main components: (i) the environment (i.e. LULC and landscape transformations), (ii) vector biology (e.g. mosquito species distributions, vector activity and life cycle, plasmodium infection rates), and (iii) human populations (e.g. forest-related activity, host susceptibility, movement patterns). In this paper, we conduct a systematic literature review on malaria risk and deforestation in the Amazon focusing on these three components. We explore key features that are likely to generate these contrasting results using the reviewed articles and our own data from Brazil and Peru, and conclude with suggestions for productive avenues in future research. This article is part of the themed issue ‘Conservation, biodiversity and infectious disease: scientific evidence and policy implications'.
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Affiliation(s)
- Joanna M Tucker Lima
- School of Forest Resources and Conservation, University of Florida, 408 McCarty Hall C, PO Box 110339, Gainesville, FL, USA
| | - Amy Vittor
- Department of Medicine, University of Florida, 408 McCarty Hall C, PO Box 110339, Gainesville, FL, USA
| | - Sami Rifai
- School of Forest Resources and Conservation, University of Florida, 408 McCarty Hall C, PO Box 110339, Gainesville, FL, USA
| | - Denis Valle
- School of Forest Resources and Conservation, University of Florida, 408 McCarty Hall C, PO Box 110339, Gainesville, FL, USA
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Spatial distribution and habitat characterization of mosquito species during the dry season along the Mara River and its tributaries, in Kenya and Tanzania. Infect Dis Poverty 2018; 7:2. [PMID: 29343279 PMCID: PMC5772712 DOI: 10.1186/s40249-017-0385-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 12/27/2017] [Indexed: 01/25/2023] Open
Abstract
Background Vector-borne diseases are increasingly becoming a major health problem among communities living along the major rivers of Africa. Although larger water bodies such as lakes and dams have been extensively researched, rivers and their tributaries have largely been ignored. This study sought to establish the spatial distribution of mosquito species during the dry season and further characterize their habitats along the Mara River and its tributaries. Methods In this cross-sectional survey, mosquito larvae were sampled along the Mara River, its two perennial tributaries (Amala and Nyangores), drying streams, and adjacent aquatic habitats (e.g. swamps, puddles that receive direct sunlight [open sunlit puddles], rock pools, hippo and livestock hoof prints, and vegetated pools). Each habitat was dipped 20 times using a standard dipper. Distance between breeding sites and human habitation was determined using global positioning system coordinates. The collected mosquito larvae were identified using standard taxonomic keys. Water physico-chemical parameters were measured in situ using a multiparameter meter. Mean mosquito larvae per habitat type were compared using analysis of variance and chi-square tests, while the relationship between mosquito larvae and physico-chemical parameters was evaluated using a generalized linear mixed model. The Cox-Stuart test was used to detect trends of mosquito larvae distribution. The test allowed for verification of monotonic tendency (rejection of null hypothesis of trend absence) and its variability. Results A total of 4001 mosquito larvae were collected, of which 2712 (67.8%) were collected from river/stream edge habitats and 1289 (32.2%) were sampled from aquatic habitats located in the terrestrial ecosystem about 50 m away from the main river/streams. Anopheles gambiae s.s, An. arabiensis, and An. funestus group, the three most potent vectors of malaria in Sub-Saharan Africa, together with other anopheline mosquitoes, were the most dominant mosquito species (70.3%), followed by Culex quinquefasciatus and Cx. pipiens complex combined (29.5%). Drying streams accounted for the highest number of larvae captured compared to the other habitat types. A stronger relationship between mosquito larvae abundance and dissolved oxygen (Z = 7.37, P ≤ 0.001), temperature (Z = 7.65, P ≤ 0.001), turbidity (Z = −5.25, P ≤ 0.001), and distance to the nearest human habitation (Z = 4.57, P ≤ 0.001), was observed. Conclusions Presence of malaria and non-malaria mosquito larvae within the Mara River basin calls for immediate action to curtail the insurgence of vector-borne diseases within the basin. A vector control program should be conducted during the dry period, targeting drying streams shown to produce the highest number of larval mosquitoes. Electronic supplementary material The online version of this article (10.1186/s40249-017-0385-0) contains supplementary material, which is available to authorized users.
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Sánchez-Ribas J, Oliveira-Ferreira J, Gimnig JE, Pereira-Ribeiro C, Santos-Neves MSA, Silva-do-Nascimento TF. Environmental variables associated with anopheline larvae distribution and abundance in Yanomami villages within unaltered areas of the Brazilian Amazon. Parasit Vectors 2017; 10:571. [PMID: 29145867 PMCID: PMC5691859 DOI: 10.1186/s13071-017-2517-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 11/01/2017] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Many indigenous villages in the Amazon basin still suffer from a high malaria burden. Despite this health situation, there are few studies on the bionomics of anopheline larvae in such areas. This publication aims to identify the main larval habitats of the most abundant anopheline species and to assess their associations with some environmental factors. METHODS We conducted a 19-month longitudinal study from January 2013 to July 2014, sampling anopheline larvae in two indigenous Yanomami communities, comprised of four villages each. All natural larval habitats were surveyed every two months with a 350 ml manual dipper, following a standardized larval sampling methodology. In a third study area, we conducted two field expeditions in 2013 followed by four systematic collections during the long dry season of 2014-2015. RESULTS We identified 177 larval habitats in the three study areas, from which 9122 larvae belonging to 13 species were collected. Although species abundance differed between villages, An. oswaldoi (s.l.) was overall the most abundant species. Anopheles darlingi, An. oswaldoi (s.l.), An. triannulatus (s.s.) and An. mattogrossensis were primarily found in larval habitats that were partially or mostly sun-exposed. In contrast, An. costai-like and An. guarao-like mosquitoes were found in more shaded aquatic habitats. Anopheles darlingi was significantly associated with proximity to human habitations and larval habitats associated with river flood pulses and clear water. CONCLUSIONS This study of anopheline larvae in the Brazilian Yanomami area detected high heterogeneities at micro-scale levels regarding species occurrence and densities. Sun exposure was a major modulator of anopheline occurrence, particularly for An. darlingi. Lakes associated with the rivers, and particularly oxbow lakes, were the main larval habitats for An. darlingi and other secondary malaria vectors. The results of this study will serve as a basis to plan larval source management activities in remote indigenous communities of the Amazon, particularly for those located within low-order river-floodplain systems.
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Affiliation(s)
- Jordi Sánchez-Ribas
- Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
- Laboratório de Mosquitos Transmissores de Hematozoários, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | | | - John E. Gimnig
- Center for Disease Control and Prevention, CDC, Atlanta, USA
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Loaiza JR, Dutari LC, Rovira JR, Sanjur OI, Laporta GZ, Pecor J, Foley DH, Eastwood G, Kramer LD, Radtke M, Pongsiri M. Disturbance and mosquito diversity in the lowland tropical rainforest of central Panama. Sci Rep 2017; 7:7248. [PMID: 28775261 PMCID: PMC5543164 DOI: 10.1038/s41598-017-07476-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 06/28/2017] [Indexed: 11/30/2022] Open
Abstract
The Intermediate Disturbance Hypothesis (IDH) is well-known in ecology providing an explanation for the role of disturbance in the coexistence of climax and colonist species. Here, we used the IDH as a framework to describe the role of forest disturbance in shaping the mosquito community structure, and to identify the ecological processes that increase the emergence of vector-borne disease. Mosquitoes were collected in central Panama at immature stages along linear transects in colonising, mixed and climax forest habitats, representing different levels of disturbance. Species were identified taxonomically and classified into functional categories (i.e., colonist, climax, disturbance-generalist, and rare). Using the Huisman-Olff-Fresco multi-model selection approach, IDH testing was done. We did not detect a unimodal relationship between species diversity and forest disturbance expected under the IDH; instead diversity peaked in old-growth forests. Habitat complexity and constraints are two mechanisms proposed to explain this alternative postulate. Moreover, colonist mosquito species were more likely to be involved in or capable of pathogen transmission than climax species. Vector species occurrence decreased notably in undisturbed forest settings. Old-growth forest conservation in tropical rainforests is therefore a highly-recommended solution for preventing new outbreaks of arboviral and parasitic diseases in anthropic environments.
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Affiliation(s)
- Jose R Loaiza
- Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Edificio 219, Clayton, PO, 0843-01103, Ciudad del Saber, Republic of Panama.
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama.
- Programa Centroamericano de Maestría en Entomología, Universidad de Panama, Panama, Republic of Panama.
| | - Larissa C Dutari
- Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Edificio 219, Clayton, PO, 0843-01103, Ciudad del Saber, Republic of Panama
| | - Jose R Rovira
- Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Edificio 219, Clayton, PO, 0843-01103, Ciudad del Saber, Republic of Panama
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Oris I Sanjur
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Gabriel Z Laporta
- Centro de Engenharia, Modelagem e Ciências Sociais Aplicadas, Universidade Federal do ABC, Santo Andre, SP, Brazil.
- Setor de Pós-graduação, Pesquisa e Inovação, Faculdade de Medicina do ABC, Santo Andre, SP, Brazil.
| | - James Pecor
- Walter Reed Biosystematics Unit, Smithsonian Institution, Museum Support Center, Suitland, MD, United States
| | - Desmond H Foley
- Walter Reed Biosystematics Unit, Smithsonian Institution, Museum Support Center, Suitland, MD, United States
| | - Gillian Eastwood
- Wadsworth Center, New York State Department of Health, Slingerlands, NY, United States
| | - Laura D Kramer
- Wadsworth Center, New York State Department of Health, Slingerlands, NY, United States
| | - Meghan Radtke
- US Environment Protection Agency, Washington DC, United States
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Adde A, Dusfour I, Vezenegho SB, Carinci R, Issaly J, Gaborit P, Nguyen C, Ardillon V, Girod R, Briolant S. Spatial and Seasonal Dynamics of Anopheles Mosquitoes in Saint-Georges de l'Oyapock, French Guiana: Influence of Environmental Factors. JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:597-605. [PMID: 28399277 DOI: 10.1093/jme/tjx031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 12/24/2016] [Indexed: 06/07/2023]
Abstract
Little is known about the Anopheles fauna of Saint-Georges de l'Oyapock, a persistent malaria-endemic municipality in French Guiana. This study aimed to update the knowledge of local Anopheles diversity, and their ecology and role in malaria transmission. Sampling sessions were implemented between September 2013 and October 2014. Four species were identified from the 3,450 specimens collected: Anopheles darlingi Root, An. braziliensis, An. triannulatus s.l., and An. nuneztovari s.l. Anopheles darlingi was the predominant species. Its involvement in malaria transmission was suspected due to 1) its abundance, 2) the presence of a density peak during the malaria emergence period, and 3) a dynamic correlated with malaria cases observed two months later. Present and past studies show that the influence of environmental conditions on malaria vector dynamics is high, and may vary drastically according to the local context. This supports evidence that control strategies must be designed at fine scales.
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Affiliation(s)
- A Adde
- Unité d'Entomologie Médicale, Institut Pasteur de la Guyane, 23 Avenue Pasteur BP 6010, 97306, Cayenne Cedex, French Guiana (; ; ; ; ; ; ; ; )
| | - I Dusfour
- Unité d'Entomologie Médicale, Institut Pasteur de la Guyane, 23 Avenue Pasteur BP 6010, 97306, Cayenne Cedex, French Guiana (; ; ; ; ; ; ; ; )
| | - S B Vezenegho
- Unité d'Entomologie Médicale, Institut Pasteur de la Guyane, 23 Avenue Pasteur BP 6010, 97306, Cayenne Cedex, French Guiana (; ; ; ; ; ; ; ; )
| | - R Carinci
- Unité d'Entomologie Médicale, Institut Pasteur de la Guyane, 23 Avenue Pasteur BP 6010, 97306, Cayenne Cedex, French Guiana (; ; ; ; ; ; ; ; )
| | - J Issaly
- Unité d'Entomologie Médicale, Institut Pasteur de la Guyane, 23 Avenue Pasteur BP 6010, 97306, Cayenne Cedex, French Guiana (; ; ; ; ; ; ; ; )
| | - P Gaborit
- Unité d'Entomologie Médicale, Institut Pasteur de la Guyane, 23 Avenue Pasteur BP 6010, 97306, Cayenne Cedex, French Guiana (; ; ; ; ; ; ; ; )
| | - C Nguyen
- Unité d'Entomologie Médicale, Institut Pasteur de la Guyane, 23 Avenue Pasteur BP 6010, 97306, Cayenne Cedex, French Guiana ( ; ; ; ; ; ; ; ; )
- Direction Interarmées du Service de Santé en Guyane, La Madeleine BP 6019, 97306, Cayenne Cedex, French Guiana
- Unité de Parasitologie et d'Entomologie Médicale, Institut de Recherche Biomédicale des Armées, Hôpital d'Instruction des Armées Laveran, 34 Boulevard Laveran, 13013, Marseille, France
- Unité de Recherche en Maladies Infectieuses Tropicales Emergentes, UMR 63, CNRS 7278, IRD 198, INSERM 1095, Faculté de Médecine La Timone, 27 Boulevard Jean Moulin, 13385, Marseille Cedex, France
| | - V Ardillon
- Cellule de l'Institut de Veille Sanitaire en Région Antilles-Guyane, Agence Régionale de Santé, 19 rue Schœlcher BP 7023, 97300, Cayenne Cedex, French Guiana
| | - R Girod
- Unité d'Entomologie Médicale, Institut Pasteur de la Guyane, 23 Avenue Pasteur BP 6010, 97306, Cayenne Cedex, French Guiana (; ; ; ; ; ; ; ; )
| | - S Briolant
- Unité d'Entomologie Médicale, Institut Pasteur de la Guyane, 23 Avenue Pasteur BP 6010, 97306, Cayenne Cedex, French Guiana ( ; ; ; ; ; ; ; ; )
- Direction Interarmées du Service de Santé en Guyane, La Madeleine BP 6019, 97306, Cayenne Cedex, French Guiana
- Unité de Parasitologie et d'Entomologie Médicale, Institut de Recherche Biomédicale des Armées, Hôpital d'Instruction des Armées Laveran, 34 Boulevard Laveran, 13013, Marseille, France
- Unité de Recherche en Maladies Infectieuses Tropicales Emergentes, UMR 63, CNRS 7278, IRD 198, INSERM 1095, Faculté de Médecine La Timone, 27 Boulevard Jean Moulin, 13385, Marseille Cedex, France
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Larval habitats of Anopheles species in a rural settlement on the malaria frontier of southwest Amazon, Brazil. Acta Trop 2016; 164:243-258. [PMID: 27650959 DOI: 10.1016/j.actatropica.2016.08.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/19/2016] [Accepted: 08/31/2016] [Indexed: 12/18/2022]
Abstract
Rural settlements are social arrangements expanding in the Amazon region, which generate disturbances in the natural environment, thus affecting the ecology of the species of Anopheles and thus the malaria transmission. Larval habitats are important sources for maintenance of mosquito vector populations, and holding back a natural watercourse is a usual process in the establishment of rural settlements, since the formation of micro-dams represents a water resource for the new settlers. Identifying characteristics of the larval habitats that may be associated with both the presence and abundance of Anopheles vectors species in an environment under ecological transition is background for planning vector control strategies in rural areas in the Amazon. Anopheles larvae collections were performed in two major types of habitats: natural and flow-limited water collections that were constructed by holding back the original watercourse. A total of 3123 Anopheles spp. larvae were captured in three field-sampling collections. The majority of the larvae identified were taken from flow-limited water collections belonged to species of the Nyssorhynchus subgenus (92%), whereas in the natural larval habitats a fewer number of individuals belonged to the Stethomyia (5%) and Anopheles (3%) subgenera. The total of Nyssorhynchus identified (1818), 501 specimens belonged to An. darlingi, 750 to An. triannulatus and 567 for others remaining species. In addition, 1152 could not be identified to subgenus/species level, because they were either in the first-instar or damaged. The primary vector in areas of the Amazon river basin, An. darlingi, was found exclusively in man-made habitats. Statistical analysis display An. triannulatus with specialist behavior for characteristics of man-made habitats. Modifications in the natural environment facilitate the rise of larval habitats for species with epidemiological importance for malaria in the region. This study showed that man-made habitats flow-limited water collections from dry lands could be a factor associated with the increase of An. darlingi and An. triannulatus populations, and other Nyssorhynchus species as well in endemic areas of the Amazon Region.
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Ramirez PG, Stein M, Etchepare EG, Almiron WR. Diversity of anopheline mosquitoes (Diptera: Culicidae) and classification based on the characteristics of the habitats where they were collected in Puerto Iguazú, Misiones, Argentina. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2016; 41:215-223. [PMID: 27860020 DOI: 10.1111/jvec.12216] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/07/2016] [Indexed: 06/06/2023]
Abstract
In order to extend the knowledge of anopheline diversity and their habitats in three environments with different degrees of anthropic intervention in Puerto Iguazú, Misiones, anopheline larvae were collected and classified on the basis of similarities of their habitats. Spatio-temporal abundance was determined and larval diversity and complementarity index were calculated. Rank-abundance curves were performed to compare the composition, abundance, and species evenness among environments. A total of 783 larvae, belonging to six species: Anopheles argyritarsis, An. fluminensis, An. mediopunctatus, An. punctimacula, An. strodei s.l., and An. triannulatus s.l., were collected. A cluster analysis and a principal component analysis detected two groups; exposure to sunlight and type of habitat were the characteristics that explained the grouping of species. Higher abundances of anopheline larvae were observed during autumn and spring. The greatest richness was recorded in wild and peri-urban environments and the effective number of species was greater in the wild. Anopheles punctimacula and An. triannulatus s.l. are secondary vectors of malaria in other South American countries and both species were found in the three environments, so that deforestation poses a potential risk for malaria transmission as it contributes to the proliferation of larval habitats for these mosquitoes.
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Affiliation(s)
- P G Ramirez
- Instituto de Medicina Regional, Universidad Nacional del Nordeste. Avenida Las Heras 727, Resistencia, Chaco, Argentina
| | - M Stein
- Instituto de Medicina Regional, Universidad Nacional del Nordeste. Avenida Las Heras 727, Resistencia, Chaco, Argentina
- CONICET - CCT Nordeste
| | - E G Etchepare
- Facultad de Ciencias Exactas Naturales y Agrimensura., Universidad Nacional del Nordeste, Corrientes, Argentina
| | - W R Almiron
- Centro de Investigaciones Entomológicas. Facultad de Ciencias Exactas, Físicas y Naturales, Instituto de Investigaciones Biológicas y Tecnológicas (IIByT-CONICET). Av. Vélez Sarsfield 1611 (X5016GCA). Universidad Nacional de Córdoba, Córdoba, Argentina
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dos Reis IC, Codeço CT, Degener CM, Keppeler EC, Muniz MM, de Oliveira FGS, Cortês JJC, de Freitas Monteiro A, de Souza CAA, Rodrigues FCM, Maia GR, Honório NA. Contribution of fish farming ponds to the production of immature Anopheles spp. in a malaria-endemic Amazonian town. Malar J 2015; 14:452. [PMID: 26573145 PMCID: PMC4647295 DOI: 10.1186/s12936-015-0947-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 10/21/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the past decade fish farming has become an important economic activity in the Occidental Brazilian Amazon, where the number of new fish farms is rapidly increasing. One of the primary concerns with this phenomenon is the contribution of fishponds to the maintenance and increase of the anopheline mosquito population, and the subsequent increase in human malaria burden. This study reports the results of a 2-year anopheline abundance survey in fishponds and natural water bodies in a malaria-endemic area in northwest Brazil. The objective of this study was to investigate the contribution of natural water bodies (rivers, streams, creeks, ponds, and puddles) and artificial fishponds as breeding sites for Anopheles spp. in Mâncio Lima, Acre and to investigate the effect of limnological and environmental variables on Anopheles spp. larval abundance. METHODS Natural water bodies and fishponds were sampled at eight different times over 2 years (early, mid and late rainy season, dry season) in the Amazonian town of Mâncio Lima, Acre. Anopheline larvae were collected with an entomological dipper, and physical, chemical and ecological characteristics of each water body were measured. Management practices of fishpond owners were ascertained with a systematic questionnaire. RESULTS Fishponds were four times more infested with anopheline larvae than natural water bodies. Electrical conductivity and the distance to the nearest house were both significant inverse predictors of larval abundance in natural water bodies. The density of larvae in fishponds raised with increasing border vegetation. Fishponds owned by different farmers varied in the extent of anopheline larval infestation but ponds owned by the same individual had similar infestation patterns over time. Commercial fishponds were 1.7-times more infested with anopheline larvae compared to fishponds for family use. CONCLUSIONS These results suggest that fishponds are important breeding sites for anopheline larvae, and that adequate management activities, such as removal of border vegetation could reduce the abundance of mosquito larvae, most importantly Anopheles darlingi.
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Affiliation(s)
- Izabel Cristina dos Reis
- Programa de Computação Científica-PROCC, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
- Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil.
- Núcleo Operacional Sentinela de Mosquitos Vetores, NOSMOVE (Parceria DIRAC-IOC-VPAAPS/FIOCRUZ), Rio de Janeiro, RJ, Brazil.
| | - Cláudia Torres Codeço
- Programa de Computação Científica-PROCC, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
| | - Carolin Marlen Degener
- Programa de Computação Científica-PROCC, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
| | | | - Mauro Menezes Muniz
- Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil.
| | | | - José Joaquin Carvajal Cortês
- Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil.
- Núcleo Operacional Sentinela de Mosquitos Vetores, NOSMOVE (Parceria DIRAC-IOC-VPAAPS/FIOCRUZ), Rio de Janeiro, RJ, Brazil.
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil.
| | | | | | | | | | - Nildimar Alves Honório
- Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil.
- Núcleo Operacional Sentinela de Mosquitos Vetores, NOSMOVE (Parceria DIRAC-IOC-VPAAPS/FIOCRUZ), Rio de Janeiro, RJ, Brazil.
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Terrazas WCM, Sampaio VDS, de Castro DB, Pinto RC, de Albuquerque BC, Sadahiro M, Dos Passos RA, Braga JU. Deforestation, drainage network, indigenous status, and geographical differences of malaria in the State of Amazonas. Malar J 2015; 14:379. [PMID: 26419523 PMCID: PMC4589039 DOI: 10.1186/s12936-015-0859-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/22/2015] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major public health problem worldwide. In Brazil, an average of 420,000 cases of malaria have been reported annually in the last 12 years, of which 99.7 % occurred in the Amazon region. This study aimed to analyse the distribution of malaria in the State of Amazonas and the influence of indigenous malaria in this scenario, to evaluate the correlation between incidence rates and socio-economic and environmental factors, and to evaluate the performance of health surveillance services. Methods This ecological study used secondary data obtained from the SIVEP-MALARIA malaria surveillance programme. The relationship between demographic, socio-economic and environmental factors, the performance of health surveillance services and the incidence of malaria in Amazonas, a multiple linear regression model was used. Results The crude rate of malaria in Amazonas was 4142.72 cases per 100,000 inhabitants between 2003 and 2012. The incidence rates for the indigenous and non-indigenous populations were 12,976.02 and 3749.82, respectively, with an indigenous population attributable fraction of only 8 %. The results of the linear regression analysis indicated a negative correlation between the two socio-economic indicators (municipal human development index (MHDI) and poverty rate) and the incidence of malaria in the period. With regard to the environmental indicators
(average annual deforestation rate and percentage of areas under the influence of watercourses), the correlation with the incidence rate was positive. Conclusions The findings underscore the importance of implementing economic and social development policies articulated with strategic actions of environmental protection and health care for the population.
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Affiliation(s)
| | | | - Daniel Barros de Castro
- Fundação de Vigilância em Saúde do Amazonas, Manaus, Brazil. .,Escola Nacional de Saúde Pública Sergio Arouca, FIOCRUZ, Rio de Janeiro, Brazil.
| | | | | | - Megumi Sadahiro
- Fundação de Vigilância em Saúde do Amazonas, Manaus, Brazil.
| | | | - José Ueleres Braga
- Escola Nacional de Saúde Pública Sergio Arouca, FIOCRUZ, Rio de Janeiro, Brazil. .,Instituto de Medicina Social, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. .,PVS PECTI-SAÚDE/Fundação de Amparo à Pesquisa do Estado do Amazonas (FAPEAM), Manaus, Amazonas, Brazil.
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Barros FSM, Honório NA. Deforestation and Malaria on the Amazon Frontier: Larval Clustering of Anopheles darlingi (Diptera: Culicidae) Determines Focal Distribution of Malaria. Am J Trop Med Hyg 2015; 93:939-53. [PMID: 26416110 DOI: 10.4269/ajtmh.15-0042] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 05/24/2015] [Indexed: 01/21/2023] Open
Abstract
We performed bimonthly mosquito larval collections during 1 year, in an agricultural settlement in the Brazilian Amazon, as well as an analysis of malaria incidence in neighboring houses. Water collections located at forest fringes were more commonly positive for Anopheles darlingi larvae and Kulldorff spatial analysis pinpointed significant larval clusters at sites directly beneath forest fringes, which were called larval "hotspots." Remote sensing identified 43 "potential" hotspots. Sampling of these areas revealed an 85.7% positivity rate for A. darlingi larvae. Malaria was correlated with shorter distances to potential hotpots and settlers living within 400 m of potential hotspots had a 2.60 higher risk of malaria. Recently arrived settlers, usually located closer to the tip of the triangularly shaped deforestation imprints of side roads, may be more exposed to malaria due to their proximity to the forest fringe. As deforestation progresses, transmission decreases. However, forest remnants inside deforested areas conferred an increased risk of malaria. We propose a model for explaining frontier malaria in the Amazon: because of adaptation of A. darlingi to the forest fringe ecotone, humans are exposed to an increased transmission risk when in proximity to these areas, especially when small dams are created on naturally running water collections.
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Affiliation(s)
- Fábio S M Barros
- Departamento de Zoologia, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Pernambuco, Brazil; Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil; Núcleo Operacional Sentinela de Mosquitos Vetores - NOSMOVE, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Nildimar A Honório
- Departamento de Zoologia, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Pernambuco, Brazil; Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil; Núcleo Operacional Sentinela de Mosquitos Vetores - NOSMOVE, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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dos Reis IC, Honório NA, de Barros FSM, Barcellos C, Kitron U, Camara DCP, Pereira GR, Keppeler EC, da Silva-Nunes M, Codeço CT. Epidemic and Endemic Malaria Transmission Related to Fish Farming Ponds in the Amazon Frontier. PLoS One 2015; 10:e0137521. [PMID: 26361330 PMCID: PMC4567347 DOI: 10.1371/journal.pone.0137521] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/17/2015] [Indexed: 11/19/2022] Open
Abstract
Fish farming in the Amazon has been stimulated as a solution to increase economic development. However, poorly managed fish ponds have been sometimes associated with the presence of Anopheles spp. and consequently, with malaria transmission. In this study, we analyzed the spatial and temporal dynamics of malaria in the state of Acre (and more closely within a single county) to investigate the potential links between aquaculture and malaria transmission in this region. At the state level, we classified the 22 counties into three malaria endemicity patterns, based on the correlation between notification time series. Furthermore, the study period (2003-2013) was divided into two phases (epidemic and post-epidemic). Higher fish pond construction coincided both spatially and temporally with increased rate of malaria notification. Within one malaria endemic county, we investigated the relationship between the geolocation of malaria cases (2011-2012) and their distance to fish ponds. Entomological surveys carried out in these ponds provided measurements of anopheline abundance that were significantly associated with the abundance of malaria cases within 100 m of the ponds (P < 0.005; r = 0.39). These results taken together suggest that fish farming contributes to the maintenance of high transmission levels of malaria in this region.
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Affiliation(s)
- Izabel Cristina dos Reis
- Programa de Computação Científica, Fiocruz, Rio de Janeiro, RJ, Brasil
- Laboratório Transmissores de Hematozoários, Instituto Oswaldo Cruz, Fiocurz, Rio de Janeiro, RJ, Brazil
| | - Nildimar Alves Honório
- Laboratório Transmissores de Hematozoários, Instituto Oswaldo Cruz, Fiocurz, Rio de Janeiro, RJ, Brazil
- Núcleo Operacional Sentinela de Mosquitos Vetores—DIRAC/IOC/VPAAPS, Fiocruz, Rio de Janeiro, RJ, Brasil
| | | | - Christovam Barcellos
- Laboratório de Informação em Saúde, Instituto de Comunicação e Informação Científica e Tecnológica em Saúde (ICICT), Fiocruz, Rio de Janeiro, RJ, Brasil
| | - Uriel Kitron
- Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America
| | | | - Glaucio Rocha Pereira
- Núcleo Operacional Sentinela de Mosquitos Vetores—DIRAC/IOC/VPAAPS, Fiocruz, Rio de Janeiro, RJ, Brasil
| | - Erlei Cassiano Keppeler
- Universidade Federal do Acre—Universidade da Floresta, Centro Multidiscipinar do Campus Floresta, Cruzeiro do Sul, Acre
| | - Mônica da Silva-Nunes
- Centro de Ciências da Saúde e do Desporto—Universidade Federal do Acre, Rio Branco, Acre
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Sánchez-Ribas J, Oliveira-Ferreira J, Rosa-Freitas MG, Trilla L, Silva-do-Nascimento TF. New classification of natural breeding habitats for Neotropical anophelines in the Yanomami Indian Reserve, Amazon Region, Brazil and a new larval sampling methodology. Mem Inst Oswaldo Cruz 2015; 110:760-70. [PMID: 26517655 PMCID: PMC4667579 DOI: 10.1590/0074-02760150168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 08/05/2015] [Indexed: 01/19/2023] Open
Abstract
Here we present the first in a series of articles about the ecology of immature stages of anophelines in the Brazilian Yanomami area. We propose a new larval habitat classification and a new larval sampling methodology. We also report some preliminary results illustrating the applicability of the methodology based on data collected in the Brazilian Amazon rainforest in a longitudinal study of two remote Yanomami communities, Parafuri and Toototobi. In these areas, we mapped and classified 112 natural breeding habitats located in low-order river systems based on their association with river flood pulses, seasonality and exposure to sun. Our classification rendered seven types of larval habitats: lakes associated with the river, which are subdivided into oxbow lakes and nonoxbow lakes, flooded areas associated with the river, flooded areas not associated with the river, rainfall pools, small forest streams, medium forest streams and rivers. The methodology for larval sampling was based on the accurate quantification of the effective breeding area, taking into account the area of the perimeter and subtypes of microenvironments present per larval habitat type using a laser range finder and a small portable inflatable boat. The new classification and new sampling methodology proposed herein may be useful in vector control programs.
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Affiliation(s)
- Jordi Sánchez-Ribas
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de
Imunoparasitologia, Rio de Janeiro, RJ, Brasil
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Mosquitos
Transmissores de Hematozoários, Rio de Janeiro, RJ, Brasil
| | - Joseli Oliveira-Ferreira
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de
Imunoparasitologia, Rio de Janeiro, RJ, Brasil
| | - Maria Goreti Rosa-Freitas
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Mosquitos
Transmissores de Hematozoários, Rio de Janeiro, RJ, Brasil
| | - Lluís Trilla
- Institut de Recerca en Energia de Catalunya, Barcelona,
Spain
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Geographically weighted regression of land cover determinants of Plasmodium falciparum transmission in the Ashanti Region of Ghana. Int J Health Geogr 2014; 13:35. [PMID: 25270342 PMCID: PMC4192530 DOI: 10.1186/1476-072x-13-35] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 09/03/2014] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a mosquito-borne parasitic disease that causes severe mortality and morbidity, particularly in Sub-Saharan Africa. As the vectors predominantly bite between dusk and dawn, risk of infection is determined by the abundance of P. falciparum infected mosquitoes in the surroundings of the households. Remote sensing is commonly employed to detect associations between land use/land cover (LULC) and mosquito-borne diseases. Due to challenges in LULC identification and the fact that LULC merely functions as a proxy for mosquito abundance, assuming spatially homogenous relationships may lead to overgeneralized conclusions. Methods Data on incidence of P. falciparum parasitaemia were recorded by active and passive follow-up over two years. Nine LULC types were identified through remote sensing and ground-truthing. Spatial associations of LULC and P. falciparum parasitaemia rate were described in a semi-parametric geographically weighted Poisson regression model. Results Complete data were available for 878 individuals, with an annual P. falciparum rate of 3.2 infections per person-year at risk. The influences of built-up areas (median incidence rate ratio (IRR): 0.94, IQR: 0.46), forest (median IRR: 0.9, IQR: 0.51), swampy areas (median IRR: 1.15, IQR: 0.88), as well as banana (median IRR: 1.02, IQR: 0.25), cacao (median IRR: 1.33, IQR: 0.97) and orange plantations (median IRR: 1.11, IQR: 0.68) on P. falciparum rate show strong spatial variations within the study area. Incorporating spatial variability of LULC variables increased model performance compared to the spatially homogenous model. Conclusions The observed spatial variability of LULC influence in parasitaemia would have been masked by traditional Poisson regression analysis assuming a spatially constant influence of all variables. We conclude that the spatially varying effects of LULC on P. falciparum parasitaemia may in fact be associated with co-factors not captured by remote sensing, and suggest that future studies assess small-scale spatial variation of vegetation to circumvent generalised assumptions on ecological associations that may in fact be artificial. Electronic supplementary material The online version of this article (doi:10.1186/1476-072X-13-35) contains supplementary material, which is available to authorized users.
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Valle D. Response to the critique by Hahn and others entitled "Conservation and malaria in the Brazilian Amazon". Am J Trop Med Hyg 2014; 90:595-6. [PMID: 24591438 PMCID: PMC3973498 DOI: 10.4269/ajtmh.14-0046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 01/31/2014] [Indexed: 11/07/2022] Open
Abstract
Hahn and others have recently criticized our study, "Conservation efforts may increase malaria burden in the Brazilian Amazon," suggesting that results were flawed because of methodological limitations. Here, we briefly comment on some of their claims, showing that (1) several of their criticisms are misleading and others are incorrect, (2) they heavily criticize methods that they themselves have previously used, and (3) they selectively highlight some findings while ignoring others. We end this rebuttal by suggesting a way forward in this debate.
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Affiliation(s)
- Denis Valle
- School of Forest Resources and Conservation, University of Florida, Gainesville, Florida
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Confalonieri UE, Margonari C, Quintão AF. Environmental change and the dynamics of parasitic diseases in the Amazon. Acta Trop 2014; 129:33-41. [PMID: 24056199 DOI: 10.1016/j.actatropica.2013.09.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 08/02/2013] [Accepted: 09/10/2013] [Indexed: 11/26/2022]
Abstract
The Amazonian environment is changing rapidly, due to deforestation, in the short term, and, climatic change is projected to alter its forest cover, in the next few decades. These modifications to the, environment have been altering the dynamics of infectious diseases which have natural foci in the, Amazonian biome, especially in its forest. Current land use practices which are changing the, epidemiological profile of the parasitic diseases in the region are road building; logging; mining; expansion of agriculture and cattle ranching and the building of large dams. Malaria and the cutaneous, leishmaniasis are the diseases best known for their rapid changes in response to environmental, modifications. Others such as soil-transmitted helminthiases, filarial infections and toxoplasmosis, which have part of their developmental cycles in the biophysical environment, are also expected to, change rapidly. An interdisciplinary approach and an integrated, international surveillance are needed, to manage the environmentally-driven changes in the Amazonian parasitic diseases in the near future.
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McKeon SN, Schlichting CD, Povoa MM, Conn JE. Ecological suitability and spatial distribution of five Anopheles species in Amazonian Brazil. Am J Trop Med Hyg 2013; 88:1079-86. [PMID: 23546804 DOI: 10.4269/ajtmh.12-0203] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Seventy-six sites characterized in Amazonian Brazil revealed distinct habitat diversification by examining the environmental factors associated with the distribution and abundance of five anopheline species (Diptera: Culicidae) in the subgenus Nyssorhynchus. These included three members of the Albitarsis Complex, Anopheles oryzalimnetes, Anopheles marajoara, Anopheles janconnae; Anopheles triannulatus, and Anopheles goeldii. Anopheles janconnae abundance had a positive correlation to water flow and a negative relationship to sun exposure. Abundance of An. oryzalimentes was associated with water chemistry. Anopheles goeldii larvae were abundant in shaded, more saline waters. Anopheles marajoara and An. triannulatus were negatively associated with available resources, although An. marajoara also showed several local correlations. These analyses suggest An. triannulatus is a habitat generalist, An. oryzalimentes and An. janconnae are specialists, and An. marajoara and An. goeldii could not be easily classified either way. Correlations described herein provide testable hypotheses for future research and identifying habitats for vector control.
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Affiliation(s)
- Sascha N McKeon
- Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, Albany, NY 12222, USA.
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Valle D, Clark J. Conservation efforts may increase malaria burden in the Brazilian Amazon. PLoS One 2013; 8:e57519. [PMID: 23483912 PMCID: PMC3590219 DOI: 10.1371/journal.pone.0057519] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 01/23/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Large-scale forest conservation projects are underway in the Brazilian Amazon but little is known regarding their public health impact. Current literature emphasizes how land clearing increases malaria incidence, leading to the conclusion that forest conservation decreases malaria burden. Yet, there is also evidence that proximity to forest fringes increases malaria incidence, which implies the opposite relationship between forest conservation and malaria. We compare the effect of these environmental factors on malaria and explore its implications. METHODS AND FINDINGS Using a large malaria dataset (~1,300,000 positive malaria tests collected over ~4.5 million km(2)), satellite imagery, permutation tests, and hierarchical Bayesian regressions, we show that greater forest cover (as a proxy for proximity to forest fringes) tends to be associated with higher malaria incidence, and that forest cover effect was 25 times greater than the land clearing effect, the often cited culprit of malaria in the region. These findings have important implications for land use/land cover (LULC) policies in the region. We find that cities close to protected areas (PA's) tend to have higher malaria incidence than cities far from PA's. Using future LULC scenarios, we show that avoiding 10% of deforestation through better governance might result in an average 2-fold increase in malaria incidence by 2050 in urban health posts. CONCLUSIONS Our results suggest that cost analysis of reduced carbon emissions from conservation efforts in the region should account for increased malaria morbidity, and that conservation initiatives should consider adopting malaria mitigation strategies. Coordinated actions from disparate science fields, government ministries, and global initiatives (e.g., Reduced Emissions from Deforestation and Degradation; Millenium Development Goals; Roll Back Malaria; and Global Fund to Fight AIDS, Tuberculosis and Malaria), will be required to decrease malaria toll in the region while preserving these important ecosystems.
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Affiliation(s)
- Denis Valle
- University Program in Ecology, Duke University, Durham, NC, USA.
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Barros FSM, Tadei WP, Arruda ME, Honório NA. On the use of classic epidemiological formulae for estimating the intensity of endemic malaria transmission by vectors in the Amazon. NEOTROPICAL ENTOMOLOGY 2012; 41:426-434. [PMID: 23950095 DOI: 10.1007/s13744-012-0065-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 06/14/2012] [Indexed: 06/02/2023]
Abstract
Although various reports have described entomological inoculation rates of malaria vector species, most were limited to providing descriptive field data. Here, we report biting rates and survival data for two important malaria vectors in the Amazon, Anopheles darlingi (Root) and Anopheles albitarsis E (Lynch-Arribalzaga) (Diptera: Culicidae), in the state of Roraima, Brazil. We calculated theoretical sporozoite infection rates and critical vector biting rates for these species during 1 year, comprising six bimestrial collections. Anopheles darlingi had higher sporozoite rates and lower critical biting rates, indicating that it would be the more efficient vector at the beginning of epidemic malaria transmission. Our data, together with compiled information from the literature in the Amazon, suggest that epidemic malaria transmission may be initiated by the primary vector, such as A. darlingi, while secondary vectors, such as A. albitarsis E, may only become epidemiologically important when there is an increase in the prevalence of human malaria. We propose that mathematical modeling may be able to quantify the relative importance of secondary vector species in malaria epidemiology.
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Affiliation(s)
- F S M Barros
- Depto de Zoologia, Univ Federal de Pernambuco, Recife, PE, Brasil
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Fuller DO, Parenti MS, Hassan AN, Beier JC. Linking land cover and species distribution models to project potential ranges of malaria vectors: an example using Anopheles arabiensis in Sudan and Upper Egypt. Malar J 2012; 11:264. [PMID: 22866895 PMCID: PMC3483279 DOI: 10.1186/1475-2875-11-264] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 07/31/2012] [Indexed: 11/10/2022] Open
Abstract
Background Anopheles arabiensis is a particularly opportunistic feeder and efficient vector of Plasmodium falciparum in Africa and may invade areas outside its normal range, including areas separated by expanses of barren desert. The purpose of this paper is to demonstrate how spatial models can project future irrigated cropland and potential, new suitable habitat for vectors such as An. arabiensis. Methods Two different but complementary spatial models were linked to demonstrate their synergy for assessing re-invasion potential of An. arabiensis into Upper Egypt as a function of irrigated cropland expansion by 2050. The first model (The Land Change Modeler) was used to simulate changes in irrigated cropland using a Markov Chain approach, while the second model (MaxEnt) uses species occurrence points, land cover and other environmental layers to project probability of species presence. Two basic change scenarios were analysed, one involving a more conservative business-as-usual (BAU) assumption and second with a high probability of desert-to-cropland transition (Green Nile) to assess a broad range of potential outcomes by 2050. Results The results reveal a difference of 82,000 sq km in potential An. arabiensis range between the BAU and Green Nile scenarios. The BAU scenario revealed a highly fragmented set of small, potential habitat patches separated by relatively large distances (maximum distance = 64.02 km, mean = 12.72 km, SD = 9.92), while the Green Nile scenario produced a landscape characterized by large patches separated by relatively shorter gaps (maximum distance = 49.38, km, mean = 4.51 km, SD = 7.89) that may be bridged by the vector. Conclusions This study provides a first demonstration of how land change and species distribution models may be linked to project potential changes in vector habitat distribution and invasion potential. While gaps between potential habitat patches remained large in the Green Nile scenario, the models reveal large areas of future habitat connectivity that may facilitate the re-invasion of An. arabiensis from Sudan into Upper Egypt. The methods used are broadly applicable to other land cover changes as they influence vector distribution, particularly those related to tropical deforestation and urbanization processes.
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Affiliation(s)
- Douglas O Fuller
- Department of Geography and Regional Studies, University of Miami, Coral Gables, FL 33124-2221, USA.
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Kano FS, Sanchez BAM, Sousa TN, Tang ML, Saliba J, Oliveira FM, Nogueira PA, Gonçalves AQ, Fontes CJF, Soares IS, Brito CFA, Rocha RS, Carvalho LH. Plasmodium vivax Duffy binding protein: baseline antibody responses and parasite polymorphisms in a well-consolidated settlement of the Amazon Region. Trop Med Int Health 2012; 17:989-1000. [PMID: 22643072 DOI: 10.1111/j.1365-3156.2012.03016.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To investigate risk factors associated with the acquisition of antibodies against Plasmodium vivax Duffy binding protein (PvDBP) - a leading malaria vaccine candidate - in a well-consolidated agricultural settlement of the Brazilian Amazon Region and to determine the sequence diversity of the PvDBP ligand domain (DBP(II)) within the local malaria parasite population. METHODS Demographic, epidemiological and clinical data were collected from 541 volunteers using a structured questionnaire. Malaria parasites were detected by conventional microscopy and PCR, and blood collection was used for antibody assays and molecular characterisation of DBP(II). RESULTS The frequency of malaria infection was 7% (6% for P. vivax and 1% for P. falciparum), with malaria cases clustered near mosquito breeding sites. Nearly 50% of settlers had anti-PvDBP IgG antibodies, as detected by enzyme-linked immunosorbent assay (ELISA) with subject's age being the only strong predictor of seropositivity to PvDBP. Unexpectedly, low levels of DBP(II) diversity were found within the local malaria parasites, suggesting the existence of low gene flow between P. vivax populations, probably due to the relative isolation of the studied settlement. CONCLUSION The recognition of PvDBP by a significant proportion of the community, associated with low levels of DBP(II) diversity among local P. vivax, reinforces the variety of malaria transmission patterns in communities from frontier settlements. Such studies should provide baseline information for antimalarial vaccines now in development.
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Affiliation(s)
- Flora S Kano
- Laboratório de Malária, Centro de Pesquisas René Rachou/Fiocruz, Belo Horizonte-MG, Brazil
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de Barros FSM, Honório NA, Arruda ME. Survivorship of Anopheles darlingi (Diptera: Culicidae) in relation with malaria incidence in the Brazilian Amazon. PLoS One 2011; 6:e22388. [PMID: 21857927 PMCID: PMC3152554 DOI: 10.1371/journal.pone.0022388] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 06/20/2011] [Indexed: 11/19/2022] Open
Abstract
We performed a longitudinal study of adult survival of Anopheles darlingi, the most important vector in the Amazon, in a malarigenous frontier zone of Brazil. Survival rates were determined from both parous rates and multiparous dissections. Anopheles darlingi human biting rates, daily survival rates and expectation of life where higher in the dry season, as compared to the rainy season, and were correlated with malaria incidence. The biting density of mosquitoes that had survived long enough for completing at least one sporogonic cycle was related with the number of malaria cases by linear regression. Survival rates were the limiting factor explaining longitudinal variations in Plasmodium vivax malaria incidence and the association between adult mosquito survival and malaria was statistically significant by logistic regression (P<0.05). Survival rates were better correlated with malaria incidence than adult mosquito biting density. Mathematical modeling showed that P. falciparum and P. malariae were more vulnerable to changes in mosquito survival rates because of longer sporogonic cycle duration, as compared to P. vivax, which could account for the low prevalence of the former parasites observed in the study area. Population modeling also showed that the observed decreases in human biting rates in the wet season could be entirely explained by decreases in survival rates, suggesting that decreased breeding did not occur in the wet season, at the sites where adult mosquitoes were collected. For the first time in the literature, multivariate methods detected a statistically significant inverse relation (P<0.05) between the number of rainy days per month and daily survival rates, suggesting that rainfall may cause adult mortality.
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