Epidemiological characterization and risk factors associated with leptospirosis in the brazilian semiarid

Alves C. J., Alcino J. F., Farias A. E. M., Higino S. S. S., Santos F. A., Azevedo S. S., Costa D. F. & Santos C. S. A. B. 2012. [Epidemiological characterization and risk factors associated with leptospirosis in the brazilian semiarid.] Caracterizacao epidemiologica e fatores de risco associados a leptospirose em ovinos deslanados do semiarido brasileiro. Pesquisa Veterinaria Brasileira 32(6): 523-528. Universidade Federal de Campina Grande, Centro de Sa de e Tecnologia Rural, Unidade Academica de Medicina Veterinaria, Av. Universitaria s/n(o), Patos, PB 58700-970, Brazil. E-mail: clebertja@uol.com.br The aim of this investigation was to determine the herd-level and animal-level prevalence of leptospirosis in sheep from the semiarid of Paraiba State, Northeast Brazil, as well as to identify risk factors. Blood samples were collected from 1,275 sheep from 117 flocks in 19 counties in the Sertao mesoregion, Paraiba. For the serological diagnosis of leptospirosis the microscopic agglutination test (MAT) using 24 Leptospira spp. serovars as antigens was carried out. Of the 117 flocks studied 33 (28.20%) presented at least one seropositive sheep, and of the 1,275 animals 69 (5.41%) were seropositive with titers ranging from 100 to 3,200. Reactant serovars were Autumnalis (49.30%), Andamana (27.53%), Sentot (17.39%), Whitcomb (4.34%) and Australis (1.44%). Herd size > 48 sheep (odds ratio = 2.26; 95% CI = 1.33-5.07; p = 0.021) and participation in animal exhibits (odds ratio = 9.05; 95% CI = 0.96-85.71; p = 0.055) were identified as risk factors. The need was suggested for studies on the isolation of the agent, characterization of its pathogenicity and its economic impact on sheep flocks of the region, and sanitary control in sheep agglomerations was recommended.

CHARACTERIZATION OF REGOSOLS IN THE SEMIARID REGION OF PERNAMBUCO, BRAZIL

CHARACTERIZATION OF REGOSOLS IN THE SEMIARID REGION OF PERNAMBUCO, BRAZIL Studies on soil characterization in unexplored regions, besides the generation of data banks for the soil classes of the country, also produce scientific information about soil properties, important for the development of good management practices and sustainable land use. One of the main soil classes in the semiarid region of Pernambuco State, the Regosols, cover about 27 % of the state area, and are used mainly for family agriculture. Due to different geological and climatic aspects Regosols with different chemical, physical and mineralogical properties are found in Pernambuco, which were characterized for the semiarid region of the State. Five Regosol profiles were selected in different regions of the State (P1=Sao Caetano; P2=Lagoa do Ouro; P3=Caetes; P4=Sao Joao; P5=Parnamirim). The soils were morphologically characterized and samples collected from all horizons and the bedrock. Routine physical and chemical analyses were carried out for soil classification of all samples and mineralogical analyses of the coarse fractions (gravel and sand) by optical microscopy and of the silt and clay fractions by X ray diffraction (XRD), as well as petrographic analyses of the rock samples. The results showed similarities between the soils, with a low degree of pedogenetic development, varying from medium to very deep, with the horizon sequence A-AC-C-Cr and a sandy to sandy loam texture. In the deeper layers of two profiles (P1 and P5), a solodic character was observed. Organic matter and available phosphorus content were low in all studied soils. Despite the low levels of exchangeable cations, all soil profiles showed high base saturation. The mineralogical composition of gravel, sand and silt fractions consisted, essentially, of quartz, followed by feldspars and mica, supporting the results of the petrographic analysis of the bedrock. Kaolinite was the main clay mineral in all studied profiles and horizons, indicating an important monosialitization process in autochthonous soils of a typical semiarid region. In soil profile P2, at a lower landscape position, smectite minerals were observed, with mixing phases of montmorillonite, beidelite or nontronite, indentified by the Greene-Kelly test in the DRX analysis.

Water transfer from São Francisco river to semiarid northeast of Brazil: technical data, environmental impacts, survey of opinion about the amount to be transferred

The transposition of the São Francisco River is considered one of the greatest engineering works in Brazil of all time since it will cross an extensive agricultural region of continental dimensions, involving environmental impacts, water, soil, irrigation, water payment and other multidisciplinary themes. Taking into account its importance, this subject was incorporated into a discipline of UFSCar (Federal University of São Carlos - Brazil) named "Pollution and Environmental Impacts". It was noted strong reaction against the project, even before the presentation. To allow a critical analysis, the first objective was to compile the main technical data and environmental impacts. The second objective was to detect the three most important aspects that cause reaction, concluding for the following reasons: assumption that the volume of water to be transferred was much greater than it actually is proposed in the project; lack of knowledge about similar project already done in Brazil; the idea that the artificial canal to be built was much broader than that proposed by the project. The participants' opinion about "volume to be transferred" was raised quantitatively four times: 2-undergraduate students; 1-graduate; 1-outside community. The average resulted 14 times larger than that proposed in the project, significant according to t-test. It was concluded that the reaction to water transfer project is due in part to the ignorance combined with a preconceived idea that tend to overestimate the magnitude of environmental impacts.

Molecular epidemiology of animal rabies in the semiarid region of Paraíba, Northeastern Brazil

In the semiarid of the state of Paraíba, the anti-rabies vaccination is not common, most of the local inhabitants who deal with the animals do not know the incidence of the disease in the region. In this study, samples of foxes (Pseudalopex vetulus), insectivorous bats (Molossus molossus), raccoons (Procyon cancrivorous) and domestic animals brains were submitted to the diagnosis of rabies, by using the direct fluorescent antibody technique (d-FAT) and mouse inoculation test (MIT). Of the 581 examined materials, 50 (8.60 %) were positive for d-FAT and 47 (8.09 %) for MIT. From the positive samples for rabies, RNAs were extracted and transformed to cDNA, at the Laboratory of Rabies/Faculdade de Medicina Veterinária e Zootecnia/USP, SP. The phylogenetic characterization of the N gene was performed at the Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, Departamento de Medicina Veterinária Preventiva e Saúde Animal, Universidade Nihon, Faculdade de Ciências Bioresource, Fujisawa, Kanagawa, Japão. Based on the results of genotyping and phylogenetic analyzes, it is concluded that the epidemiology of rabies is complex in the semiarid of Paraíba, with different viral variants being maintained in domestic dogs, foxes, insectivorous bats and vampire bats. All the isolates examined belong to the genotype I of the genus Lyssavirus and it is possible to state that in the region, foxes are important sylvatic reservoirs of the rabies virus.

Evapotranspiration and crop coefficients of rice (Oryza sativa L.) under sprinkler irrigation in a semiarid climate determined by the surface renewal method

The evapotranspiration (ETc) of sprinkler-irrigated rice was determined for the semiarid conditions of NE Spain during 2001, 2002 and 2003. The surface renewal method, after calibration against the eddy covariance method, was used to obtain values of sensible heat flux (H) from high-frequency temperature readings. Latent heat flux values were obtained by solving the energy balance equation. Finally, lysimeter measurements were used to validate the evapotranspiration values obtained with the surface renewal method. Seasonal rice evapotranspiration was about 750–800 mm. Average daily ETc for mid-season (from 90 to 130 days after sowing) was 5.1, 4.5 and 6.1 mm day−1 for 2001, 2002 and 2003, respectively. The experimental weekly crop coefficients fluctuated in the range of 0.83–1.20 for 2001, 0.81–1.03 for 2002 and 0.84–1.15 for 2003. The total growing season was about 150–160 days. In average, the crop coefficients for the initial (Kcini), mid-season (Kcmid) and late-season stages (Kcend) were 0.92, 1.06 and 1.03, respectively, the length of these stages being about 55, 45 and 25 days, respectively.

Trace Elements Distribution in Red Soils under Semiarid Mediterranean Environment

This study states the potential trace elements (TE’s) content of red soils located at the centre region of Spain, characterized by low rainfall and slight acidity over prolonged weathering periods. For this purpose, three soil profiles from a catena were described, sampled and analyzed. The most notable characteristics are the low organic matter content and the predominantly acidic pH. Illite and kaolinite are the predominant clay minerals. The fertility of the soils is sufficient to provide most of the nutrients required, with very suitable potassium levels. The geochemical characters of this soil are: only few elements remain almost invariable across the profiles and over time, however the majority of them were directly linked with the clay content. These soils are characterized by relatively low levels of some trace elements such as Sr (64.35 mg?kg–1), Ba (303.67 mg?kg–1) and Sc (13.14 mg?kg–1); high levels of other trace elements such as V (103.92 mg?kg–1), Cr (79.9 mg?kg–1), Cu (15.18 mg?kg–1), Hf (10.26 mg?kg–1), Ni (38 mg?kg–1) and Zr (337 mg?kg–1); while the levels for rare earth elements (REE’s) such as La (48.36 mg?kg–1), Ce (95.07 mg?kg–1), Th (13.33 mg?kg–1) and Nd (42.65 mg?kg–1) are significantly high. The distribution of mayor and trace elements was directly re- lated to weathering processes, parent material and anthropogenic activities.

Nitrogen deposition alters nitrogen cycling and reduces soil carbon content in low-productivity semiarid Mediterranean ecosystems.

Anthropogenic N deposition poses a threat to European Mediterranean ecosystems. We combined data from an extant N deposition gradient (4.3–7.3 kg N ha−1 yr−1) from semiarid areas of Spain and a field experiment in central Spain to evaluate N deposition effects on soil fertility, function and cyanobacteria community. Soil organic N did not increase along the extant gradient. Nitrogen fixation decreased along existing and experimental N deposition gradients, a result possibly related to compositional shifts in soil cyanobacteria community. Net ammonification and nitrification (which dominated N-mineralization) were reduced and increased, respectively, by N fertilization, suggesting alterations in the N cycle. Soil organic C content, C:N ratios and the activity of β-glucosidase decreased along the extant gradient in most locations. Our results suggest that semiarid soils in low-productivity sites are unable to store additional N inputs, and that are also unable to mitigate increasing C emissions when experiencing increased N deposition.

Improving simulation of soil water balance using lysimeter observations in a semiarid climate.

Water balance simulation in cropping systems is a very useful tool to study how water can be used efficiently. However this requires that models simulate an accurate water balance. Comparing model results with field observations will provide information on the performance of the models. The objective of this study was to test the performance of DSSAT model in simulating the water balance by comparing the simulations with observed measurements. The soil water balance in DSSAT uses a one dimensional ?tipping bucket? soil water balance approach where available soil water is determined by the drained upper limit (DUL), lower limit (LL) and saturated water content (SAT). A continuous weighing lysimeter was used to get the observed values of drainage and evapotranspiration (ET). An automated agrometeorological weather station close to the lisymeter was also used to record the climatic data. The model simulated accurately the soil water content after the optimization of the soil parameters. However it was found the inability of the model to capture small changes in daily drainage and ET. For that reason simulated cumulative values had larger errors as the time passed by. These results suggested the need to compare outputs of DSSAT and some hydrological model that simulates soil water movement with a more mechanistic approach. The comparison of the two models will allow us to find which mechanism can be modified or incorporated in DSSAT model to improve the simulations.

Aridity modulates N availability in arid and semiarid Mediterranean grasslands

While much is known about the factors that control each component of the terrestrial nitrogen (N) cycle, it is less clear how these factors affect total N availability, the sum of organic and inorganic forms potentially available to microorganisms and plants. This is particularly true for N-poor ecosystems such as drylands, which are highly sensitive to climate change and desertification processes that can lead to the loss of soil nutrients such as N. We evaluated how different climatic, abiotic, plant and nutrient related factors correlate with N availability in semiarid Stipa tenacissima grasslands along a broad aridity gradient from Spain to Tunisia. Aridity had the strongest relationship with N availability, suggesting the importance of abiotic controls on the N cycle in drylands. Aridity appeared to modulate the effects of pH, plant cover and organic C (OC) on N availability. Our results suggest that N transformation rates, which are largely driven by variations in soil moisture, are not the direct drivers of N availability in the studied grasslands. Rather, the strong relationship between aridity and N availability could be driven by indirect effects that operate over long time scales (decades to millennia), including both biotic (e.g. plant cover) and abiotic (e.g. soil OC and pH). If these factors are in fact more important than short-term effects of precipitation on N transformation rates, then we might expect to observe a lagged decrease in N availability in response to increasing aridity. Nevertheless, our results suggest that the increase in aridity predicted with ongoing climate change will reduce N availability in the Mediterranean basin, impacting plant nutrient uptake and net primary production in semiarid grasslands throughout this region.

Biogeochemical indicators of elevated nitrogen deposition in semiarid Mediterranean ecosystems

Nitrogen (N) deposition has doubled the natural N inputs received by ecosystems through biological N fixation and is currently a global problem that is affecting the Mediterranean regions. We evaluated the existing relationships between increased atmospheric N deposition and biogeochemical indicators related to soil chemical factors and cryptogam species across semiarid central, southern, and eastern Spain. The cryptogam species studied were the biocrust-forming species Pleurochaete squarrosa (moss) and Cladonia foliacea (lichen). Sampling sites were chosen in Quercus coccifera (kermes oak) shrublands and Pinus halepensis (Aleppo pine) forests to cover a range of inorganic N deposition representative of the levels found in the Iberian Peninsula (between 4.4 and 8.1 kg N ha(-1) year(-1)). We extended the ambient N deposition gradient by including experimental plots to which N had been added for 3 years at rates of 10, 20, and 50 kg N ha(-1) year(-1). Overall, N deposition (extant plus simulated) increased soil inorganic N availability and caused soil acidification. Nitrogen deposition increased phosphomonoesterase (PME) enzyme activity and PME/nitrate reductase (NR) ratio in both species, whereas the NR activity was reduced only in the moss. Responses of PME and NR activities were attributed to an induced N to phosphorus imbalance and to N saturation, respectively. When only considering the ambient N deposition, soil organic C and N contents were positively related to N deposition, a response driven by pine forests. The PME/NR ratios of the moss were better predictors of N deposition rates than PME or NR activities alone in shrublands, whereas no correlation between N deposition and the lichen physiology was observed. We conclude that integrative physiological measurements, such as PME/NR ratios, measured on sensitive species such as P. squarrosa, can provide useful data for national-scale biomonitoring programs, whereas soil acidification and soil C and N storage could be useful as additional corroborating ecosystem indicators of chronic N pollution.

The NH3-Abating effect of Slurry Injection as Influenced by Soil Moisture in a Semiarid Arable Soil

Accumulation of large volumes of dilute slurries is considered one of the major problems related to intensive farming (Sommer et al., 2004). In the EU-27, more than half of the total N excretion is applied to croplands due to technical advantages for farmers (e.g. reuse of nutrients). However, the N use efficiency of slurries produced by livestock is low, i.e. only 20-52% of the excreted N is recovered by crops. Much of the remainder can be lost into the atmosphere as ammonia (NH3), nitrous oxide (N2O), dinitrogen (N2) and nitrogen oxides (NOx).

Cluster microclimate (light and thermal) is a key point of grape maturity in mediterranean semiarid conditions

Se estudian la influencia en el microclima de racimos (temperatura e iluminación) de tres sistemas de conducción en la variedad Syrah en una zona calida.

Fish diversity and traditional fishing methods in semiarid irrigated system in the Bajo Vinalopó region, Southeastern Spain

The aim of this paper is to obtain a comprehensive picture of the importance of the fish fauna in the wetlands and coastal lagoons of the Bajo Vinalopó region (Alicante, South eastern Spain) and the ecological, historical and cultural value of the traditional knowledge on fishing maintained by local people. We have compiled data from different information sources: (1) the revision of historical archives, (2) personal interviews and collaborative research, and (3) ecological and water quality data. The results show that the area sustains important fish fauna diversity (17 species) and that local people have inherited a considerable traditional knowledge on fishing methods (11 modalities), on the maintenance and sound management of the water system and on the ecology and behaviour of fish. We conclude that a comprehensive consideration of all these ecological, historical and socio-cultural aspects related to fish and fishing shows clearly the value of this ecological and cultural heritage and provides a necessary base for a sustainable management of the area.

Arid and semiarid land stewardship : a 10-year review of accomplishments and contributions of the International Arid Lands Consortium /

"November 2001."