Guagliardo S.A.,Emory University |
Barboza J.L.,University of the Amazon |
Morrison A.C.,University of California at Davis |
Astete H.,Naval Medical Research Unit No 6 Namru 6 Iquitos Laboratory |
And 4 more authors.
PLoS Neglected Tropical Diseases | Year: 2014
Background and Objectives: In the Peruvian Amazon, the dengue vector Aedes aegypti is abundant in large urban centers such as Iquitos. In recent years, it has also been found in a number of neighboring rural communities with similar climatic and socioeconomic conditions. To better understand Ae. aegypti spread, we compared characteristics of communities, houses, and containers in infested and uninfested communities. Methods: We conducted pupal-demographic surveys and deployed ovitraps in 34 communities surrounding the city of Iquitos. Communities surveyed were located along two transects: the Amazon River and a 95km highway. We calculated entomological indices, mapped Ae. aegypti presence, and developed univariable and multivariable logistic regression models to predict Ae. aegypti presence at the community, household, or container level. Results: Large communities closer to Iquitos were more likely to be infested with Ae. aegypti. Within infested communities, houses with Ae. aegypti had more passively-filled containers and were more often infested with other mosquito genera than houses without Ae. aegypti. For containers, large water tanks/drums and containers with solar exposure were more likely to be infested with Ae. aegypti. Maps of Ae. aegypti presence revealed a linear pattern of infestation along the highway, and a scattered pattern along the Amazon River. We also identified the geographical limit of Ae. aegypti expansion along the highway at 19.3 km south of Iquitos. Conclusion: In the Peruvian Amazon, Ae. aegypti geographic spread is driven by human transportation networks along rivers and highways. Our results suggest that urban development and oviposition site availability drive Ae. aegypti colonization along roads. Along rivers, boat traffic is likely to drive long-distance dispersal via unintentional transport of mosquitoes on boats. © 2014.
Lahteenoja O.,University of Turku |
Reategui Y.R.,University of the Amazon |
Rasanen M.,University of Turku |
Torres D.D.C.,Institute Investigaciones Of La Amazonia Peruana Iiap |
And 2 more authors.
Global Change Biology | Year: 2012
The carbon (C) dynamics of tropical peatlands can be of global importance, because, particularly in Southeast Asia, they are the source of considerable amounts of C released to the atmosphere as a result of land-use change and fire. In contrast, the existence of tropical peatlands in Amazonia has been documented only recently. According to a recent study, the 120 000 km 2 subsiding Pastaza-Marañón foreland basin in Peruvian Amazonia harbours previously unstudied and up to 7.5 m thick peat deposits. We studied the role of these peat deposits as a C reserve and sink by measuring peat depth, radiocarbon age and peat and C accumulation rates at 5-13 sites. The basal ages varied from 1975 to 8870 cal yr bp, peat accumulation rates from 0.46 to 9.31 mm yr -1 and C accumulation rates from 28 to 108 g m -2 yr -1. The total peatland area and current peat C stock within the area of two studied satellite images were 21 929 km 2 and 3.116 Gt (with a range of 0.837-9.461 Gt). The C stock is 32% (with a range of 8.7-98%) of the best estimate of the South American tropical peatland C stock and 3.5% (with a range of 0.9-10.7%) of the best estimate of the global tropical peatland C stock. The whole Pastaza-Marañón basin probably supports about twice this peatland area and peat C stock. In addition to their contemporary geographical extent, these peatlands probably also have a large historical (vertical) extension because of their location in a foreland basin characterized by extensive river sedimentation, peat burial and subsidence for most of the Quaternary period. Burial of peat layers in deposits of up to 1 km thick Quaternary river sediments removes C from the short-term C cycle between the biosphere and atmosphere, generating a long-term C sink. © 2011 Blackwell Publishing Ltd.
Kristiansen T.,University of Aarhus |
Svenning J.-C.,University of Aarhus |
Pedersen D.,University of Aarhus |
Eiserhardt W.L.,University of Aarhus |
And 2 more authors.
Journal of Ecology | Year: 2011
1.Local and regional patterns of plant species richness in tropical rain forests, as well as their possible drivers, remain largely unexplored. The main hypotheses for local species richness (alpha diversity) are (i) local environmental determinism with species-saturated communities, and (ii) regional control, in which the immigration of species from the regional species pool (gamma diversity) determines how many species coexist locally. The species pool hypothesis suggests a combined influence of local and regional drivers on alpha diversity. Differences in gamma diversity may arise from divergent environmental conditions or biogeographic histories. 2.We investigated the cross-scale determinants of palm alpha and gamma diversity across the western Amazon using a large field-based data set: a census of all palm individuals in 312 transects, totalling 98 species. We used regression-based variation partitioning to understand how habitat, topography and region influence alpha diversity, and correlations to assess the importance of the present environment (climate, soil, regional topography) and history (long-term habitat stability) for average regional alpha diversity and gamma diversity, including the link between these two diversity measures (species pool effect). 3.Variation in alpha diversity was primarily explained by region (36%) and habitat (18%), whereas the effect of topography was negligible (1%). Within habitats, region was even more important (up to 69% explained variation). Within regions, habitat and topography covaried and had a variable but an important influence. The pure effect of topography remained of minor importance (up to 13%). 4.Average regional alpha diversity was related to gamma diversity, precipitation seasonality and possibly long-term habitat stability. Gamma diversity was related to long-term habitat stability, and possibly current climate. 5.Synthesis. Gamma diversity strongly influenced alpha diversity, although a clear influence of local environment was also evident, notably habitat type, with a minor, more geographically variable effect of small-scale topography. Apart from gamma diversity, the factor most strongly related to regional alpha diversity was precipitation seasonality, while gamma diversity itself was strongly linked to long-term habitat stability. These results imply that plant species richness is contingent on both contemporary and historical factors with a strong link between local species richness and the regional species pool. © 2011 The Authors. Journal of Ecology © 2011 British Ecological Society.
Mosquera O.,Laboratory of Analytical Services |
Buurman P.,Wageningen University |
Ramirez B.L.,University of the Amazon |
Amezquita M.C.,Fundacion Universitaria Catolica
Geoderma | Year: 2012
To evaluate the effect of land use change on soil organic carbon, the carbon contents and stocks of primary forest, degraded pasture, and four improved pasture systems in Colombian Amazonia were compared in a flat and a sloping landscape. The improved pastures were Brachiaria humidicola, and Brachiaria decumbens, either in monoculture or in combination with native legumes. The age of the treatments was 30years for degraded pasture and 10 or 15years for each of the improved pastures. Carbon fractions were Total C, Oxidizable C, and Non-Oxidizable (stable) C. Stocks were compared using a fixed soil mass base. The degraded pasture in the flat landscape was abandoned and dominated by weeds, while that in the sloping area was overgrazed. The latter had much lower C stocks than the former. B. humidicola monoculture had the highest stocks both in flat and sloping areas, while the effect of the other three treatments varied. C replacement based on δ 13C indicated that after 30years, the degraded pasture still contained more than 50% forest-derived C in its topsoil. The fraction in the topsoil that is not replaced roughly coincides with the Stable C fraction δ 13C values suggest that the changes in carbon stocks ascribed to differences in land use may be - at least partially - inherited from the previous land use, thus confusing the interpretation of land use effects. Nevertheless, the introduction of improved pastures on degraded grassland is a feasible alternative of land use both for carbon sequestration and as an attractive economic alternative to farmers. © 2012 Elsevier B.V.
Sutton P.L.,New York University |
Clark E.H.,University of Alabama at Birmingham |
Silva C.,University of the Amazon |
Branch O.H.,New York University
Malaria Journal | Year: 2010
Background. Plasmodium falciparum re-emerged in Iquitos, Peru in 1994 and is now hypoendemic (< 0.5 infections/person/year). Purportedly non-immune individuals with discrete (non-overlapping) P. falciparum infections can be followed using this population dynamic. Previous work demonstrated a strong association between this population's antibody response to PfMSP1-19KD and protection against febrile illness and parasitaemia. Therefore, some selection for PfMSP1-19KD allelic diversity would be expected if the protection is to allele-specific sites of PfMSP1-19KD. Here, the potential for allele-specific polymorphisms in this population is investigated, and the allele-specificity of antibody responses to PfMSP1-19KD are determined. Methods. The 42KD region in PfMSP1 was genotyped from 160 individual infections collected between 2003 and 2007. Additionally, the polymorphic block 2 region of Pfmsp1 (Pfmsp1-B2) was genotyped in 781 infection-months to provide a baseline for population-level diversity. To test whether PfMSP1-19KD genetic diversity had any impact on antibody responses, ELISAs testing IgG antibody response were performed on individuals using all four allele-types of PfMSP1-19KD. An antibody depletion ELISA was used to test the ability of antibodies to cross-react between allele-types. Results. Despite increased diversity in Pfmsp1-B2, limited diversity within Pfmsp1-42KD was observed. All 160 infections genotyped were Mad20-like at the Pfmsp1-33KD locus. In the Pfmsp1-19KD locus, 159 (99.4%) were the Q-KSNG-F haplotype and 1 (0.6%) was the E-KSNG-L haplotype. Antibody responses in 105 individuals showed that Q-KNG and Q-TSR alleles generated the strongest immune responses, while Q-KNG and E-KNG responses were more concordant with each other than with those from Q-TSR and E-TSR, and vice versa. The immuno-depletion ELISAs showed all samples responded to the antigenic sites shared amongst all allelic forms of PfMSP1-19KD. Conclusions. A non-allele specific antibody response in PfMSP1-19KD may explain why other allelic forms have not been maintained or evolved in this population. This has important implications for the use of PfMSP1-19KD as a vaccine candidate. It is possible that Peruvians have increased antibody responses to the shared sites of PfMSP1-19KD, either due to exposure/parasite characteristics or due to a human-genetic predisposition. Alternatively, these allelic polymorphisms are not immune-specific even in other geographic regions, implying these polymorphisms may be less important in immune evasion that previous studies suggest. © 2010 Sutton et al; licensee BioMed Central Ltd.
Halsey E.S.,Us Naval Medical Research Unit No 6 |
Siles C.,Us Naval Medical Research Unit No 6 |
Guevara C.,Us Naval Medical Research Unit No 6 |
Vilcarromero S.,Us Naval Medical Research Unit No 6 |
And 4 more authors.
Emerging Infectious Diseases | Year: 2013
During 2010-2013, we recruited 16 persons with confirmed Mayaro virus infection in the Peruvian Amazon to prospectively follow clinical symptoms and serologic response over a 12-month period. Mayaro virus infection caused long-term arthralgia in more than half, similar to reports of other arthritogenic alphaviruses.
Trujillo-C. W.,University of the Amazon |
Correa-Munera M.,University of the Amazon
Caldasia | Year: 2010
We investigated the plants used by a Coreguaje indigenous community located in the upper Caquetá, colombian Amazon. With the participation of ten native informants, we surveyed the plant species in the following usable spaces within the Gorgonia reservation: secondary forest, stubble fields, chagras, home gardens and pastures. We recorded the common names and use of plants grouped in thirteen use categories. From the Use Value (UV) (using the methodology of totalized uses) and Preference Value (PV), we identified the species of the greatest importance to the community andtested for differences in PV of medicinal plants between two informants. We present ethnobotanical information for 171 species (137 genera in 62 families); 72 species are used as medicinal, 38 in construction and 33 as food, thus representing the three most important use categories. UV depends on plant abundance in the secondary forest (r = 0.388, p = 0.001, n = 65). About 72% of the 90 arboreal species (DBH ≥ 10 cm) found in 0.2 ha of secondary forest are used in at least one of the use categories, mainly as building material, lumber and food. The secondary forest was the most valuable used space with 76 useful plants. Siparuna decipiens, Socratea exorrhiza, Wittmackanthus stanleyanus and Vismia sp. were the plant species with the highest use value (UV = 3), whereas Rauvolfi a leptophylla had the highest PV. Given that the latter species is rarely found in the colombian Amazon and is currently experiencing habitat loss in the study area, we suggest its inclusion in ex-situ plans of conservation. There was not a significant difference (p>0.05) in the preference value of medicinal plants between the two informants surveyed, suggesting a common ethnomedical knowledge system.
Sutton P.L.,New York University |
Torres L.P.,University of the Amazon |
Branch O.H.,New York University
Malaria Journal | Year: 2011
Background: The aim of this study was to consider the impact that multi-clone, complex infections have on a parasite population structure in a low transmission setting. In general, complexity of infection (minimum number of clones within an infection) and the overall population level diversity is expected to be minimal in low transmission settings. Additionally, the parasite population structure is predicted to be clonal, rather than sexual due to infrequent parasite inoculation and lack of recombination between genetically distinct clones. However, in this low transmission of the Peruvian Amazon, complex infections are becoming more frequent, in spite of decreasing infection prevalence. In this study, it was hypothesized that sexual recombination between distinct clonal lineages of Plasmodium falciparum parasites were altering the subpopulation structure and effectively maintaining the population-level diversity. Methods. Fourteen microsatellite markers were chosen to describe the genetic diversity in 313 naturally occurring P. falciparum infections from Peruvian Amazon. The population and subpopulation structure was characterized by measuring: clusteredness, expected heterozygosity (He), allelic richness, private allelic richness, and linkage disequilibrium. Next, microsatellite haplotypes and alleles were correlated with P. falciparum merozoite surface protein 1 Block 2 (Pfmsp1-B2) to examine the presence of recombinant microsatellite haplotypes. Results: The parasite population structure consists of six genetically diverse subpopulations of clones, called "clusters". Clusters 1, 3, 4, and 6 have unique haplotypes that exceed 70% of the total number of clones within each cluster, while Clusters 2 and 5 have a lower proportion of unique haplotypes, but still exceed 46%. By measuring the He, allelic richness, and private allelic richness within each of the six subpopulations, relatively low levels of genetic diversity within each subpopulation (except Cluster 4) are observed. This indicated that the number of alleles, and not the combination of alleles, are limited. Next, the standard index of association (IA S) was measured, which revealed a significant decay in linkage disequilibrium (LD) associated with Cluster 6, which is indicative of independent assortment of alleles. This decay in LD is a signature of this subpopulation approaching linkage equilibrium by undergoing sexual recombination. To trace possible recombination events, the two most frequent microsatellite haplotypes observed over time (defined by either a K1 or Mad20) were selected as the progenitors and then potential recombinants were identified in within the natural population. Conclusions: Contrary to conventional low transmission models, this study provides evidence of a parasite population structure that is superficially defined by a clonal backbone. Sexual recombination does occur and even arguably is responsible for maintaining the substructure of this population. © 2011 Sutton et al; licensee BioMed Central Ltd.
Recharte Uscamaita M.,University of the Amazon |
Bodmer R.,University of Kent
ORYX | Year: 2010
The giant otter Pteronura brasiliensis was hunted almost to extinction in the Peruvian Amazon during a period of professional trade in wild animal skins during 1920-1973. In 1973 the Department of Agriculture of Peru (INRENA) prohibited commercial hunting in the Peruvian Amazon, and the giant otter was included in Appendix I of CITES. From 1973 to 2004 giant otter populations experienced a slow recovery in numerous rivers of the Peruvian Amazon. Here, we report the population growth of the giant otter on the Yavarí- Mirín and Yavar Rivers in north-east Peru. The first evaluations of giant otter populations in these rivers, in which no individuals were sighted, were in 1992-1993. During surveys in 1996 and 1997 two individuals were sighted. In 2001, 19 individuals were sighted and in 2003 and 2004, 41 individuals were observed. This increase demonstrates a slow recovery and shows that the population has not yet reached its carrying capacity. The prohibition of international trade in otter skins by CITES, supported by INRENA, helped the population recover and was important in the conservation of this species. © 2009 Fauna & Flora International.
Branch O.H.,New York University |
Sutton P.L.,New York University |
Barnes C.,Instituto Nacional Of Salud |
Castro J.C.,University of the Amazon |
And 3 more authors.
Molecular Biology and Evolution | Year: 2011
Plasmodium falciparum entered into the Peruvian Amazon in 1994, sparking an epidemic between 1995 and 1998. Since 2000, there has been sustained low P. falciparum transmission. The Malaria Immunology and Genetics in the Amazon project has longitudinally followed members of the community of Zungarococha (N = 1,945, 4 villages) with active household and health center-based visits each year since 2003. We examined parasite population structure and traced the parasite genetic diversity temporally and spatially. We genotyped infections over 5 years (2003-2007) using 14 microsatellite (MS) markers scattered across ten different chromosomes. Despite low transmission, there was considerable genetic diversity, which we compared with other geographic regions. We detected 182 different haplotypes from 302 parasites in 217 infections. Structure v2.2 identified five clusters (subpopulations) of phylogenetically related clones. To consider genetic diversity on a more detailed level, we defined haplotype families (hapfams) by grouping haplotypes with three or less loci differences. We identified 34 different hapfams identified. The Fst statistic and heterozygosity analysis showed the five clusters were maintained in each village throughout this time. A minimum spanning network (MSN), stratified by the year of detection, showed that haplotypes within hapfams had allele differences and haplotypes within a cluster definition were more separated in the later years (2006-2007). We modeled hapfam detection and loss, accounting for sample size and stochastic fluctuations in frequencies overtime. Principle component analysis of genetic variation revealed patterns of genetic structure with time rather than village. The population structure, genetic diversity, appearance/disappearance of the different haplotypes from 2003 to 2007 provides a genome-wide "real-time" perspective of P. falciparum parasites in a low transmission region. © 2011 The Author.