927 resultados para Savanna biome
Seasonality and relative abundance of Tabanidae (Diptera) captured on horses in the Pantanal, Brazil
Resumo:
Once a month, from June 1992 to May 1993, collections of tabanids on horse were conducted in the Nhecolândia, Pantanal State of Mato Grosso do Sul, Brazil. Tabanid catches using hand nets were conducted from sunrise to sunset at grassland and cerradão (dense savanna) habitats. A total of 3,442 tabanids from 21 species,12 genera, and 3 subfamilies were collected. Although species abundance varied seasonally depending on habitat, no habitat specificity was observed for the most abundant species. In the grassland, 1,625 (47.2%) tabanids belonging to 19 species were collected, while 1,817 (52.8%) tabanids from 17 species were caught in the cerradão. The number of tabanid species varied from 7 during winter (July/August) to 15 in the spring (October). Tabanus importunus (56%) was the most abundant species, followed by T. occidentalis (8.2%), and T. claripennis (8.1%). The tabanid peak, in October, coincided with the beginning of the rainy season. The population peak of most species, including those with higher vector potential, suggests that the rainy season can be considered as the period of potentially higher risk of mechanical transmission of pathogens by tabanids to horses in the region.
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The distribution of Anopheles gambiae and An. arabiensis across the ecological zones of Nigeria (arid savanna in the north gradually turns into humid forest in the south) was investigated. Results of the present study were compared to the distributions determined from samples of indoor-resting females reported by an earlier study over 20 years ago. Larvae were sampled in the rainy seasons of 1997 and 1999 from 24 localities, 10 of which were sampled in both years. Specimens were identified by the polymerase chain reaction method. Results showed that species composition changed significantly among the 10 localities in both years (chi2=13.62, P = 0.0002), but this change was significant in only four of the 10 localities. The identity of the prevalent (more abundant) species changed between 1997 and 1999 in only three of 10 localities. An. arabiensis was prevalent in several localities in the southern Guinea savanna, an area where it was virtually absent over 20 years ago. The data suggest that An. arabiensis has extend its range, although differences in sampling technique (larval sampling versus adult collection) can not be ruled out as a possible explanation.
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Los carbonales son un tipo de bosque secundario originados por el abandono de un sistema de producción silvopastoril. Estos parches de bosque ocupan una superficie importante de la zona de amortiguamiento de la Reserva Natural del Tisey-La Estanzuela, área del bioma más amenazado del mundo, el Bosque Seco Tropical. La principal especie que compone esta comunidad vegetal es la Acacia pennatula, conocida comúnmente como carbón. Actualmente no hay muchos estudios sobre los carbonales, por lo que el presente proyecto pretende caracterizar la estructura y composición de la comunidad y describir algunos índices ecológicos básicos, en dos estadios diferentes. El análisis de los datos proporciona información de las principales diferencias en cuanto a estructura y composición que tienen lugar en los carbonales. La disminución natural de la densidad de individuos de A. pennatula con los años, parece tener un efecto positivo sobre la diversidad, composición y estructura de la comunidad. En base a estos datos, se ha diseñado un protocolo para realizar un estudio experimental de estas comunidades en el CIEA “El Limón”. En el protocolo, mediante diferentes tratamientos de tala en estadios tempranos, se obtendrán áreas de estudio que presenten un gradiente en la variable densidad de individuos de A. pennatula. El objetivo principal es describir y comparar la estructura, composición y dinámica del carbonal a lo largo del tiempo, y determinar que efecto tiene sobre la comunidad modificar esta variable. Los resultados obtenidos en el protocolo pueden utilizarse como base para desarrollar un plan de manejo para los carbonales que facilite la restauración del Bosque Tropical Seco y el aprovechamiento forestal.
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The modern approach to the development of new chemical entities against complex diseases, especially the neglected endemic diseases such as tuberculosis and malaria, is based on the use of defined molecular targets. Among the advantages, this approach allows (i) the search and identification of lead compounds with defined molecular mechanisms against a defined target (e.g. enzymes from defined pathways), (ii) the analysis of a great number of compounds with a favorable cost/benefit ratio, (iii) the development even in the initial stages of compounds with selective toxicity (the fundamental principle of chemotherapy), (iv) the evaluation of plant extracts as well as of pure substances. The current use of such technology, unfortunately, is concentrated in developed countries, especially in the big pharma. This fact contributes in a significant way to hamper the development of innovative new compounds to treat neglected diseases. The large biodiversity within the territory of Brazil puts the country in a strategic position to develop the rational and sustained exploration of new metabolites of therapeutic value. The extension of the country covers a wide range of climates, soil types, and altitudes, providing a unique set of selective pressures for the adaptation of plant life in these scenarios. Chemical diversity is also driven by these forces, in an attempt to best fit the plant communities to the particular abiotic stresses, fauna, and microbes that co-exist with them. Certain areas of vegetation (Amazonian Forest, Atlantic Forest, Araucaria Forest, Cerrado-Brazilian Savanna, and Caatinga) are rich in species and types of environments to be used to search for natural compounds active against tuberculosis, malaria, and chronic-degenerative diseases. The present review describes some strategies to search for natural compounds, whose choice can be based on ethnobotanical and chemotaxonomical studies, and screen for their ability to bind to immobilized drug targets and to inhibit their activities. Molecular cloning, gene knockout, protein expression and purification, N-terminal sequencing, and mass spectrometry are the methods of choice to provide homogeneous drug targets for immobilization by optimized chemical reactions. Plant extract preparations, fractionation of promising plant extracts, propagation protocols and definition of in planta studies to maximize product yield of plant species producing active compounds have to be performed to provide a continuing supply of bioactive materials. Chemical characterization of natural compounds, determination of mode of action by kinetics and other spectroscopic methods (MS, X-ray, NMR), as well as in vitro and in vivo biological assays, chemical derivatization, and structure-activity relationships have to be carried out to provide a thorough knowledge on which to base the search for natural compounds or their derivatives with biological activity.
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The aim of the present study, in view of the widespread geographical distribution of Lutzomyia (Nyssomyia) whitmani s.l. in Brazil, in close association with the regions of transmission of Leishmania (Viannia) braziliensis and L. (V.) shawi, is to investigate the distribution of this sand fly species and American cutaneous leishmaniasis (ACL) in relationship to vegetation and landscape ecology throughout Brazil. Thematic maps were elaborated by the MapInfo programme, giving information on the spatial distribution of L. whitmani s.l., in accordance with types of vegetation and foci of ACL. With regards to the known areas of transmission of ACL in Brazil, it is notable that L. (N.) whitmani s.l. occurs in most of them, where it has been implicated as a possible vector of L. (V.) braziliensis. The presence of L. whitmani s.l. has been registered in 26 states, the one exception being Santa Catarina; in some states such as Roraima, Acre, Tocantins, and Mato Grosso do Sul this sand fly species has been recorded in a large number of municipalities. L. whitmani s.l. has been found in association with a variety of vegetation types, including the Amazonian forest, savanna ("campos cerrados"), and northeastern savanna ("caatingas nordestinas" or "savana estépica").
Resumo:
Malaria control has been directed towards regional actions where more detailed knowledge of local determinants of transmission is of primary importance. This is a short report on range distribution and biting indices for Anopheles darlingi and An. albitarsis during the dry and rainy season that follows river level variation in a savanna/alluvial forest malaria system area in the Northern Amazon Basin. Distribution range and adult biting indices were at their highest during the rainy season for both An. darlingi and An. albitarsis. During the rainy season the neighboring alluvial forest was extensively flooded. This coincided with highest rates in malaria transmission with case clustering near the river. As the river receded, anopheline distribution range and density decreased. This decrease in distribution and density corresponded to a malaria decrease in the near area. An exponential regression function was derived to permit estimations of An. darlingi distribution over specified distances. Anopheline spatio-temporal variations lead to uneven malaria case distribution and are of important implications for control strategies.
Resumo:
The risk that Chagas disease becomes established as a major endemic threat in Amazonia (the world's largest tropical biome, today inhabited by over 30 million people) relates to a complex set of interacting biological and social determinants. These include intense immigration from endemic areas (possibly introducing parasites and vectors), extensive landscape transformation with uncontrolled deforestation, and the great diversity of wild Trypanosoma cruzi reservoir hosts and vectors (25 species in nine genera), which maintain intense sylvatic transmission cycles. Invasion of houses by adventitious vectors (with infection rates > 60%) is common, and focal adaptation of native triatomines to artificial structures has been reported. Both acute (~ 500) and chronic cases of autochthonous human Chagas disease have been documented beyond doubt in the region. Continuous, low-intensity transmission seems to occur throughout the Amazon, and generates a hypoendemic pattern with seropositivity rates of ~ 1-3%. Discrete foci also exist in which transmission is more intense (e.g., in localized outbreaks probably linked to oral transmission) and prevalence rates higher. Early detection-treatment of acute cases is crucial for avoiding further dispersion of endemic transmission of Chagas disease in Amazonia, and will require the involvement of malaria control and primary health care systems. Comprehensive eco-epidemiological research, including prevalence surveys or the characterization of transmission dynamics in different ecological settings, is still needed. The International Initiative for Chagas Disesae Surveillance and Prevention in the Amazon provides the framework for building up the political and scientific cooperation networks required to confront the challenge of preventing Chagas disease in Amazonia.
Resumo:
Leptospirosis is a zoonotic disease affecting most mammals and is distributed throughout the world. Several species of domestic and wild animals may act as reservoirs for this disease. The purpose of this study was to assess the exposure of free-ranging wild carnivores, horses and domestic dogs on a private reserve located in the northern Pantanal (Brazil) and the surrounding areas to Leptospira spp from 2002-2006, 75 free-ranging wild carnivores were captured in the Pantanal and serum samples were collected. In addition, samples from 103 domestic dogs and 23 horses in the region were collected. Serum samples were tested for the presence of Leptospira antibodies using the microscopic agglutination test. Thirty-two wild carnivores (42.7%) were considered positive with titres > 100, and 18 domestic dogs (17.5%) and 20 horses (74.1%) were also found to be positive. Our study showed that horses, dogs and several species of free-ranging wild carnivores have been exposed to Leptospira spp in the Pantanal, suggesting that the peculiar characteristics of this biome, such as high temperatures and an extended period of flooding, may favour bacterial persistence and transmission. In this region, wild carnivores and horses seem to be important hosts for the epidemiology of Leptospira species.
Resumo:
Adult ticks of the species Amblyomma parvum were collected from the vegetation in the Pantanal biome (state of Mato Grosso do Sul) and from horses in the Cerrado biome (state of Piauí) in Brazil. The ticks were individually tested for rickettsial infection via polymerase chain reaction (PCR) targeting three rickettsial genes, gltA, ompA and ompB. Overall, 63.5% (40/63) and 66.7% (2/3) of A. parvum ticks from Pantanal and Cerrado, respectively, contained rickettsial DNA, which were all confirmed by DNA sequencing to be 100% identical to the corresponding fragments of the gltA, ompA and ompB genes of Candidatus Rickettsia andeanae. This report is the first to describe Ca. R. andeanae in Brazil.
Resumo:
The lethality of malaria in the extra-Amazonian region is more than 70 times higher than in Amazonia itself. Recently, several studies have shown that autochthonous malaria is not a rare event in the Brazilian southeastern states in the Atlantic Forest biome. Information about autochthonous malaria in the state of Rio de Janeiro (RJ) is scarce. This study aims to assess malaria cases reported to the Health Surveillance System of the State of Rio de Janeiro between 2000-2010. An average of 90 cases per year had parasitological malaria confirmation by thick smear. The number of malaria notifications due to Plasmodium falciparum increased over time. Imported cases reported during the period studied were spread among 51% of the municipalities (counties) of the state. Only 35 cases (4.3%) were autochthonous, which represents an average of 3.8 new cases per year. Eleven municipalities reported autochthonous cases; within these, six could be characterised as areas of residual or new foci of malaria from the Atlantic Forest system. The other 28 municipalities could become receptive for transmission reintroduction. Cases occurred during all periods of the year, but 62.9% of cases were in the first semester of each year. Assessing vulnerability and receptivity conditions and vector ecology is imperative to establish the real risk of malaria reintroduction in RJ.
Resumo:
Traps are widely employed for sampling and monitoring mosquito populations for surveillance, ecological and fauna studies. Considering the importance of assessing other technologies for sampling mosquitoes, we addressed the effectiveness of Mosquito Magnet® Independence (MMI) in comparison with those of the CDC trap with CO2 and Lurex3® (CDC-A) and the CDC light trap (CDC-LT). Field collections were performed in a rural area within the Atlantic Forest biome, southeastern state of São Paulo, Brazil. The MMI sampled 53.84% of the total number of mosquitoes, the CDC-A (26.43%) and CDC-LT (19.73%). Results of the Pearson chi-squared test (χ2) showed a positive association between CDC-LT and species of Culicini and Uranotaeniini tribes. Additionally, our results suggested a positive association between CDC-A and representatives of the Culicini and Aedini tribes, whereas the MMI was positively associated with the Mansoniini and Sabethini as well as with Anophelinae species. The MMI sampled a greater proportion (78.27%) of individuals of Anopheles than either the CDC-LT (0.82%) or the CDC-A traps (20.91%). Results of the present study showed that MMI performed better than CDC-LT or CDC-A in sampling mosquitoes in large numbers, medically important species and assessing diversity parameters in rural southeastern Atlantic Forest.
Resumo:
The Amazon Fund, created in 2008 by the Brazilian Federal Government, is managed by Banco Nacional de Desenvolvimento Econômico e Social (BNDES). It is a pioneering initiative to fundraise and manage financial resources to cut back deforestation and support sustainable development for 30 million inhabitants in the Amazon Biome. The Amazon Fund has already received more than R$ 1.7 billion in grants (about USD 787 million). This essay analyzes the Amazon Fund's governance and management with focus on its operation and from its stakeholders' perspectives. A combination of research methods includes: documental research, in-depth interviews, and speech analysis. The study offers a comparative analysis of strengths and weaknesses related to its governance. Furthermore, it proposes ways to improve its management towards greater effectiveness. The essay also includes an assessment of the government of Norway, a major donor to the fund. The governments of Norway and Germany, in partnership with Brazil, reveal how important it is to experiment with new means of international cooperation to successfully reduce greenhouse gas emissions through rainforest preservation.
Resumo:
Keskushermosto- ja neonataali-infektiot ovat herpes simplex -virusten aiheuttamista taudeista vakavimpia. Niihin on olemassa lääkitys, joka on tehokkain, kun se aloitetaan aivan sairauden alkuvaiheessa. Näiden infektioiden diagnostiikassa PCR-menetelmä on herkin. Tämä menetelmä on kuitenkin työläs ja aikaa vievä, joten uudet nopeammat menetelmät ovat tervetulleita. Opinnäytetyö tehtiin HUSLABin virologian osastolle. Työssä testattiin QIAGENIN artus®HSV-1/2 LC PCR-reagenssipakkausta, joka on tehty käytettäväksi Roche diagnosticsin reaaliaikaisella PCR-laitteella LightCyclerillä. Lisäksi työssä testattiin automaattista bioMérieuxin NucliSens easyMAG- nukleiinihappoeristyslaitetta. Referenssinä käytettiin HUSLABin virologian osastolla testaushetkellä käytössä olevia menetelmiä. Reaaliaikaisen PCR-menetelmän herkkyyttä testattiin positiivisilla HSV-1 ja HSV-2 kontrollilaimennussarjoilla. Menetelmän oikeellisuutta testattiin määrittämällä laaduntarkkailu- ja potilasnäytteitä, jotka olivat likvoria. Tuloksia verrattiin QCMD:n antamiin ja perinteisellä ”in house”- PCR-menetelmällä saatuihin referenssituloksiin. Spesifisyyttä testattiin muiden ihmisten herpesvirusten positiivisilla kontrolleilla. Automaattisen nukleiinihappoeristysmenetelmän toimivuutta testattiin HSV-positiivisilla ja -negatiivisilla likvornäytteillä, jotka oli aikaisemmin eristetty fenoli-kloroformiuutolla. Tulokset QIAGENIN artus®HSV-1/2 LC PCR-reagenssipakkauksesta olivat hyviä. Kont-rollilaimennussarjan määrityksessä reaaliaikainen PCR-menetelmä osoittautui perinteistä ”in house”- PCR-menetelmää herkemmäksi. Potilasnäytteiden määrityksessä tulokset olivat yhtenevät. EasyMAG- nukleiinihappoeristysmenetelmällä eristettyjen potilasnäytteiden määrityksistä saadut tulokset olivat myös hyviä. Kun tuloksia verrattiin fenoli-kloroformiuutolla saatuihin tuloksiin, olivat tulokset yhtä näytettä lukuun ottamatta yhtenevät. Molemmat testattavat menetelmät ovat nopeita ja virhelähteiden mahdollisuus on vähäisempi kuin perinteisessä ”in house”-PCR menetelmässä ja fenoli-kloroformiuutolla nukleiinihappoa eristettäessä. Tutkimusten tulokset osoittivat molempien menetelmien soveltuvan hyvin HSV:n eristykseen ja määritykseen likvornäytteistä.
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Riparian forests are important features of any ecosystem, especially on grassland and savannah vegetation types. However, riparian forests in southernmost Brazil have received much less attention than elsewhere. This is the first quantitative study of pentatomoid (Hemiptera) diversity in the Pampa biome, surveying riparian forests of brooks and rivers in the environs of the municipality of Bagé, Rio Grande do Sul state, southern Brazil. The aim was two-fold: taxonomic characterization of the fauna and a primary ecological study of bug diversity. Sweeping net and beating tray were used to sample trees and shrubs on the border of sampling sites; sampling was carried out during three consecutive days, from March 28th to 30th 2006. Overall 154 individuals of 32 species of Pentatomoidea were captured, almost all species are new records for the local fauna. Taller forest canopy sites had higher abundance overall and higher species richness than shorter forest canopy sites. Of the 32 species, 11 were singletons and four were doubletons. There were no differences for pentatomoid species composition between the two environments differing in vegetation structure. Association to the Pampa biome of the most abundant species found are discussed. Although based on a rapid assessment protocol of faunal inventories, our results add important bioecological information to the pentatomoid fauna of the Pampa biome, especially associated to riparian forests.
Resumo:
The knowledge on Atlantic Forest scarab beetle fauna is quite limited. This biome is strongly degraded and these insects can be used as bioindicators since they are sensitive to forest destruction and show distinct organizational patterns in forest fragments or in areas that have been deteriorated by human activity. Thus, a study of the Scarabaeidae (sensu stricto) dung beetles fauna that inhabit Serra do Japi, São Paulo, Brazil (23º12'-23º22' S and 46º53'-47º03'W) was carried out; the monthly species richness was analyzed in six areas during one year and the vegetation's structural physiognomy was described. The areas included a conserved and a degraded valley, a northward and a southward hillside, a hilltop, and an area of secondary forest growing under eucalyptus trees. The specimens were collected using four pitfall traps baited with human feces, which remained at each spot during 48 hours. Between September, 1997 and August, 1998, 3524 individuals of 39 species were collected; the most abundant were: Canthidium trinodosum, Eurysternus cyanescens, Uroxys kratochvili, Scybalocanthon nigriceps, Uroxys lata, Canthonella sp., Dichotomius assifer, Deltochilum furcatum, Canthidium sp.2, Canthon latipes, Deltochilum rubripenne, Eurysternus sp., and Dichotomius sp.1. The number of individuals and species was greater in the hot, rainy season, when there was a correlation between the number of species and the mean annual temperature [r²= 0.69; p<0.01]. The lower winter richness was most pronounced in the conserved valley, while richness remained relatively constant in the degraded valley; abundance was much higher in the degraded valley. The cluster analysis showed that the valleys and hillsides are the most similar in relation to species composition and abundance, yet different from the secondary forest with eucalypts and the hilltop.