994 resultados para rainy season onset


Relevância:

80.00% 80.00%

Publicador:

Resumo:

From January to December 1998, nasopharyngeal aspirates were obtained from 482 children with acute respiratory infections attended in emergence department and wards of a teaching hospital in the city of Salvador, Brazil. The samples were tested for the presence of adenovirus by isolation in tissue culture and indirect immunofluorescence assay. Eleven adenoviruses were detected by both methods in the same clinical samples. Infections by adenovirus were observed during seven months of the year without association with rainy season. Genome analysis was performed on these 11 isolates. Species C was represented by serotypes 1, 2 and 5. Within species B, only serotype 7 (Ad7) was detected. Two genomic variants of Ad1, two variants of Ad2, one of Ad5, and one of Ad7 (7h) were identified. This is the first study of molecular epidemiology of adenovirus associated to acute respiratory infections in children living in Northeast Brazil, and contributes to a better understanding of adenovirus infections in the country.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The Triannulatus Complex of Anopheles (Nyssorhynchus) consists of at least three sibling species, namely Anopheles triannulatus s.s., Anopheles halophylus and a third undescribed member herein referred to as An. triannulatus "C". Sympatric anophelines belonging to species complexes, even though closely related, may exploit different environments such as larval habitats. In this paper we hypothesize that rainfall and seasonal flooding would distinctly influence the availability of larval habitats and consequently the seasonal population dynamics of sympatric members of the Triannulatus Complex. A reflection of this is distinct seasonal biting frequencies exhibited by three members of the Triannulatus Complex at a site in Central Brazil. Population dynamics seem to be influenced by the water level in the local rivers, although biting frequency of all three species was negatively influenced by rainfall. An. triannulatus s.s. was more abundant following the end of the rainy season, but notably 30 to 60 days after flooding. On the other hand, An. halophylus and An. triannulatus C peaked during the middle of the dry season, when water impoundments have no inflow, are somewhat reduced in size and the water becomes brackish. Differences in population dynamics were greater between An. triannulatus s.s. and An. halophylus and An. triannulatus C than between An. halophylus and An. triannulatus C. This might reflect differences in larval habitat exploitation and therefore spatial segregation among these members of the complex.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The bionomics of sand flies (Diptera: Phlebotominae) was studied monthly for two consecutive years in alluvial gallery forests in the department of Casanare, Northeastern Colombia. A total of 2,365 specimens and 10 species were captured using CDC light traps and Shannon traps, and from diurnal resting places, and human landing collections. Lutzomyia fairtigi Martins (55%), Lutzomyia micropyga (Mangabeira) (20.9%), and Lutzomyia antunesi (Coutinho) (13.5%) were the predominant species in the region. Lutzomyia flaviscutellata and Lutzomyia panamensis, potential vectors of Leishmania in Colombia and neighboring countries, were also collected, but in low numbers. Lu. fairtigi is an endemic species to Colombia, and minimal data are available on its biology and distribution. The present study provides additional information about Lu. fairtigi, such as the diurnal activity displayed by females on cloudy days, the greater density during the rainy season (April to October), marked anthropophilia, and the presence of flagellates in the midgut of one female.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

French Guiana is one of the areas in South America most affected by malaria and where the disease has become a serious public health problem. In spite of this situation, little recent entomological data are available from the main localities where the disease occurs, even though they are crucial for development of an effective vector control strategy. A longitudinal entomological survey was carried out from March 2000-February 2002 in three Amerindian villages, namely Twenké, Taluène and Cayodé, located in the Amazonian forest of the Upper-Maroni area, to assess anopheline mosquitoes and malaria transmission dynamics. Anopheles darlingi (Diptera: Culicidae) was the most abundant mosquito species caught during the study. This efficient American malaria vector was active the entire year, but showed an evident peak of abundance during the main rainfall season, from April-June, with an average human biting rate of 255.5 bites per person per night. Parity rates were homogeneous all year, indicating no significant seasonal variability in female survival rates. Estimated vectorial capacity indices were higher during the rainy season, even though the risk of transmission was present throughout the year (VCI > 1). A total of 14 An. darlingi were found infected with Plasmodium falciparum, Plasmodium vivax or Plasmodium malariae. The annual circumsporozoite indices were 0.15, 0.14 and 0.05, and the entomological inoculation rates were 22.8, 27.4 and 14.4 infected bites per person per year in Twenké, Taluène and Cayodé, respectively. An. darlingiwas endo-exophagic and rather exophilic in these localities. The species was collected throughout the night but was more aggressive between 21:30-03:30 h and after 05:30 h. Parity rates were homogeneous during the entire night. Impregnated hammock and/or bed nets, coupled with the use of mosquito repellents, as well as the early treatment of malarial cases, appear to be the most suitable tools for fighting malaria in these Amerindian villages since the spraying of residual insecticides is inefficient because of vector biology and the housing structure.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

In Brazil, visceral leishmaniasis (VL) is caused by Leishmania chagasi parasites that are transmitted to man through the bites of infected females of Lutzomyia longipalpis sand flies. In order to evaluate transmission risk and to clarify the epidemiology of this tropical disease, studies focused on the vector and favorable environmental conditions are of fundamental importance. In this work, we surveyed the phlebotomine sand fly fauna in Janaúba, a Brazilian municipality that is endemic for VL. During a two-year period, entomological captures were performed monthly in 15 districts with high, moderate and low profiles of VL transmission. A total of 14,591 phlebotomine sand flies were captured (92% L. longipalpis), with a predominance of males. Most specimens were captured in the peri-domicile setting, although the number of specimens captured in the intra-domicile setting emphasises the anthropophilic behaviour of this insect. The population density of L. longipalpis was modulated by climate variations, particularly with clear increases immediately after the rainy season. However, the pattern of distribution did not coincide with the occurrence of human or canine cases of VL. This suggests that the eco-epidemiology of VL is particular to each area of transmission and must be taken into account during the design of public health control actions.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Objectives Exposure assessment to a single pesticide does not capture the complexity of the occupational exposure. Recently, pesticide use patterns analysis has emerged as an alternative to study these exposures. The aim of this study is to identify the pesticide use pattern among flower growers in Mexico participating in the study on the endocrine and reproductive effects associated with pesticide exposure. Methods A cross-sectional study was carried out to gather retrospective information on pesticide use applying a questionnaire to the person in charge of the participating flower growing farms. Information about seasonal frequency of pesticide use (rainy and dry) for the years 2004 and 2005 was obtained. Principal components analysis was performed. Results Complete information was obtained for 88 farms and 23 pesticides were included in the analysis. Six principal components were selected, which explained more than 70% of the data variability. The identified pesticide use patterns during both years were: 1. fungicides benomyl, carbendazim, thiophanate and metalaxyl (both seasons), including triadimephon during the rainy season, chlorotalonyl and insecticide permethrin during the dry season; 2. insecticides oxamyl, biphenthrin and fungicide iprodione (both seasons), including insecticide methomyl during the dry season; 3. fungicide mancozeb and herbicide glyphosate (only during the rainy season); 4. insecticides metamidophos and parathion (both seasons); 5. insecticides omethoate and methomyl (only rainy season); and 6. insecticides abamectin and carbofuran (only dry season). Some pesticides do not show a clear pattern of seasonal use during the studied years. Conclusions The principal component analysis is useful to summarise a large set of exposure variables into smaller groups of exposure patterns, identifying the mixtures of pesticides in the occupational environment that may have an interactive effect on a particular health effect.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

In this study we compared two polymerase chain reaction (PCR) methods using either 16S ribosomal RNA (rRNA) or 23S rRNA gene primers for the detection of different Leptospira interrogans serovars. The performance of these two methods was assessed using DNA extracted from bovine tissues previously inoculated with several bacterial suspensions. PCR was performed on the same tissues before and after the formalin-fixed, paraffin-embedding procedure (FFPE tissues). The 23S rDNA PCR detected all fresh and FFPE positive tissues while the 16S rDNA-based protocol detected primarily the positive fresh tissues. Both methods are specific for pathogenic L. interrogans. The 23S-based PCR method successfully detected Leptospira in four dubious cases of human leptospirosis from archival tissue specimens and one leptospirosis-positive canine specimen. A sensitive method for leptospirosis identification in FFPE tissues would be a useful tool to screen histological specimen archives and gain a better assessment of human leptospirosis prevalence, especially in tropical countries, where large outbreaks can occur following the rainy season.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Phlebotomine sandflies are the vectors for the protozoan parasites that cause leishmaniasis. The present study investigated the species composition of sandfly fauna in the rural district of Taquaruçú, municipality of Palmas, state of Tocantins, Brazil and compared the diversity of species among intradomicile, peridomicile and forest environments during the dry and rainy seasons. Sandflies were collected using CDC light traps over the course of three months during the dry and rainy seasons. A total of 767 specimens were captured, belonging to different 32 species. The most abundant species were Micropygomyia goiana (Martins, Falcão & Silva), Sciopemyia sordellii (Shannon & Del Ponte), Evandromyia carmelinoi (Ryan Fraiha, Lainson & Shaw), Evandromyia termitophila (Martins, Falcão & Silva), Nyssomyia whitmani (Antunes & Coutinho) and Lutzomyia longipalpis (Lutz & Neiva). The highest species diversity (30) and the greatest percentage of specimens (78.3%) were obtained during the rainy season. During the dry season, the species richness and abundance were greater in domestic environments. However, during the rainy season, the forest displayed the highest species richness and the domestic environment exhibited the greatest species abundance. Several important vector species are reported in this study.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Cape Verde, located off the coast of Senegal in western Africa, is a volcanic archipelago where a combination of human, climatic, geomorphologic and pedologic factors has led to extensive degradation of the soils. Like other Sahelian countries, Cape Verde has suffered the effects of desertification through the years, threatening the livelihood of the islands population and its fragile environment. In fact, the steep slopes in the ore agricultural islands, together with semi-arid and arid environments, characterized by an irregular and poorly distributed rainy season, with high intensity rainfall events, make dryland production a challenge. To survive in these fragile conditions, the stabilization of the farming systems and the maintenance of sustainable yields have become absolute priorities, making the islands an erosion control laboratory. Soil and water conservation strategies have been a centerpiece of the government0s agricultural policies for the last half century. Aiming to maintain the soil in place and the water inside the soil, the successive governments of Cape Verde have implemented a number of soil and water conservation techniques, the most common ones being terraces, half moons, live barriers, contour rock walls, contour furrows and microcatchments, check dams and reforestation with drought resistant species. The soil and water conservation techniques implemented have contributed to the improvement of the economical and environmental conditions of the treated landscape, making crop production possible, consequently, improving the livelihood of the people living on the islands. In this paper, we survey the existing soil and water conservation techniques, analyze their impact on the livelihood condition of the population through a thorough literature review and field monitoring using a semi-quantitative methodology and evaluate their effectiveness and impact on crop yield in the Ribeira Seca watershed. A brief discussion is given on the cost and effectiveness of the techniques to reduce soil erosion and to promote rainfall infiltration. Finally, we discuss the critical governance factors that lead to the successful implementation of such strategy in a country with scarce natural resources.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The present study was carried out in three localities of the state of São Paulo, Brazil: Araras (Dec/03-Dec/06), São Carlos (Nov/04-Nov/06) and Rifaina (Jul/04-Dec/06). Trap-nests were distributed among sites in the sampling areas and were collected every 35 days. Data from 295 nests indicate that T. aurifrons is a multivoltine species, with higher rates of nest building and cell production in the warm, rainy season. The trap-nests used by the females ranged from 117 to 467 mm in length and 3.1 to 16.6 mm in diameter. All nests showed deep plugs and a vestibular cell was found in 37% of the complete nests. The number of cells per nest ranged from one to 12. Females were larger than males, emerged from longer cells and their cocoons were significantly larger. A secondary 1:1 sex ratio was found in Araras and Rifaina. No correlation was observed between the diameter of the trap-nest and sex ratio. Males were usually oviposited in the first brood cells. Male and female developmental time from egg to adult was longer in the cold, dry season. Trypoxylon aurifrons provisioned their nests mainly with orb-spiders from the family Araneidae. The most important mortality factor was the death of immature forms, probably due to development failure. The most important parasitoid was Melittobia sp.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The plant architecture hypothesis predicts that variation in host plant architecture influences insect herbivore community structure, dynamics and performance. In this study we evaluated the effects of Macairea radula (Melastomataceae) architecture on the abundance of galls induced by a moth (Lepidoptera: Gelechiidae). Plant architecture and gall abundance were directly recorded on 58 arbitrarily chosen M. radula host plants in the rainy season of 2006 in an area of Cerrado vegetation, southeastern Brazil. Plant height, dry biomass, number of branches, number of shoots and leaf abundance were used as predicting variables of gall abundance and larval survival. Gall abundance correlated positively with host plant biomass and branch number. Otherwise, no correlation (p > 0.05) was found between gall abundance with shoot number or with the number of leaves/plant. From a total of 124 galls analyzed, 67.7% survived, 14.5% were attacked by parasitoids, while 17.7% died due to unknown causes. Larvae that survived or were parasitized were not influenced by architectural complexity of the host plant. Our results partially corroborate the plant architecture hypothesis, but since parasitism was not related to plant architecture it is argued that bottom-up effects may be more important than top-down effects in controlling the population dynamics of the galling lepidopteran. Because galling insects often decrease plant fitness, the potential of galling insects in selecting for less architectural complex plants is discussed.

Relevância:

80.00% 80.00%

Publicador:

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.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

In Cape Verde, the low soil cover and inadequate practices on rain fed agricultural lands constitute major problems related to desertification. To the fragility of the land associates severe water erosion, causing tons of land to be washed away from the fields every year during the rainy season. Therefore, the aim in the scope of combating desertification is to provide a certain degree of permanent soil cover to serve as shield for the impact of rain. During the selection workshop several technologies, all related to vegetative cover either as strips or surface cover were discussed. Only two technologies were selected: vegetation strip with pigeon pea and afforestation with fruit trees.  Technology 1: Pigeon pea (cajanus cajan) barriers/strips. It consists in planting seeds of pigeon pea, a leguminous perennial shrub that has dual purpose of protecting the soil and feed people. It is planted in association with maize crop. After the maize is harvested, the soil remains with some degree of cover. Though the objective was to plant as strip barriers, six meters apart, most farmers planted it as surface cover.  Technology 2: Afforestation with fruit trees. It consists in the plantation of different fruit tree species in humid areas to provide both soil cover and feed for farmers. Since fruit trees require several years to provide effective cover, and though it was implemented in some areas, it was not evaluated during the project’s period.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

In Cape Verde, the low soil cover and inadequate practices on rain fed agricultural lands constitute major problems related to desertification. To the fragility of the land associates severe water erosion, causing tons of land to be washed away from the fields every year during the rainy season. Therefore, the aim in the scope of combating desertification is to provide a certain degree of permanent soil cover to serve as shield for the impact of rain. During the selection workshop several technologies, all related to vegetative cover either as strips or surface cover were discussed. Only two technologies were selected: vegetation strip with pigeon pea and afforestation with fruit trees.  Technology 1: Pigeon pea (cajanus cajan) barriers/strips. It consists in planting seeds of pigeon pea, a leguminous perennial shrub that has dual purpose of protecting the soil and feed people. It is planted in association with maize crop. After the maize is harvested, the soil remains with some degree of cover. Though the objective was to plant as strip barriers, six meters apart, most farmers planted it as surface cover.  Technology 2: Afforestation with fruit trees. It consists in the plantation of different fruit tree species in humid areas to provide both soil cover and feed for farmers. Since fruit trees require several years to provide effective cover, and though it was implemented in some areas, it was not evaluated during the project’s period.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The archipelago of Cape Verde is made up of ten islands and nine islets and is located between latitudes 14º 28' N and 17º 12' N and longitudes 22º 40' W and 25º 22' W. It is located approximately 500 km from the Senegal coast in West Africa (Figure 1). The islands are divided into two groups: Windward and Leeward. The Windward group is composed of the islands of Santo Antão, São Vicente, Santa Luzia, São Nicolau, Sal and Boavista; and the Leeward group is composed of the islands Maio, Santiago, Fogo and Brava. The archipelago has a total land surface of 4,033 km2 and an Economic Exclusive Zone (ZEE) that extends for approximately 734,000 km2. In general, the relief is very steep, culminating with high elevations (e.g. 2,829 m on Fogo and 1,979 m on Santo Antão). The surface area, geophysical configuration and geology vary greatly from one island to the next. Cape Verde, due to its geomorphology, has a dense and complex hydrographical network. However, there are no permanent water courses and temporary water courses run only during the rainy season. These temporary water courses drain quickly towards the main watersheds, where, unless captured by artificial means, continue rapidly to lower areas and to the sea. This applies equally to the flatter islands. The largest watershed is Rabil with an area of 199.2 km2. The watershed areas on other islands extend over less than 70 km2. Cape Verde is both a least developed country (LDC) and a small island development state (SIDS). In 2002, the population of Cape Verde was estimated at approximately 451,000, of whom 52% were women and 48% men. The population was growing at an average 2.4% per year, and the urban population was estimated at 53.7 %. Over the past 15 years, the Government has implemented a successful development strategy, leading to a sustained economic growth anchored on development of the private sector and the integration of Cape Verde into the world economy. During this period, the tertiary sector has become increasingly important, with strong growth in the tourism, transport, banking and trade sectors. Overall, the quality of life indicators show substantial improvements in almost all areas: housing conditions, access to drinking water and sanitation, use of modern energy in both lighting and cooking, access to health services and education. Despite these overall socio-economic successes, the primary sector has witnessed limited progress. Weak performance in the primary sector has had a severe negative impact on the incomes and poverty risks faced by rural workers1. Moreover, relative poverty has increased significantly during the past decade. The poverty profile shows that: (i) extreme poverty is mostly found in rural areas, although it has also increased in urban areas; (ii) poverty is more likely to occur when the head of the household is a woman; (iii) poverty increases with family size; (iv) education significantly affects poverty; (v) the predominantly agricultural islands of Santo Antão and Fogo have the highest poverty rates; (vi) unemployment affects the poor more than the nonpoor; (vii) agriculture and fisheries workers are more likely to be poor than those in other sectors. Therefore, the fight against poverty and income inequalities remains one of the greatest challenges for Cape Verde authorities. The various governments of Cape Verde over the last decade have demonstrated a commitment to improving governance, notably by encouraging a democratic culture that guarantees stability and democratic changes without conflicts. This democratic governance offers a space for a wider participation of citizens in public management and consolidates social cohesion. However, there are some remaining challenges related to democratic governance and the gains must be systematically monitored. Finally, it is worth emphasizing that the country’s insularity has stimulated a movement to decentralized governance, although social inequalities and contrasts from one island to the next constitute, at the same time, challenges and opportunities.