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Exposure to mercury is often assessed by the measurement of molecular and biochemical antioxidant defences against an excessive production of reactive oxygen species. Here we examined some selected biomarkers of oxidative stress in the earthworm Lumbricus terrestris short- (2d) and long-term (44 d) exposed to Hg-contaminated soils (up to 1287 mg/kg dry wt). This level of Hg exposure did not cause earthworm mortality, however it yielded organisms to a situation of oxidative stress which was evidenced by the time-dependent responses of biomarkers. The reduced to oxidized glutathione ratio was a sensitive and early biomarker of Hg exposure, although the glutathione reductase activity back returned their normal physiological concentrations. Metallothioneins and total glutathione seemed to have a significant role in reducing Hg-induced oxidative stress when exposure to Hg prolonged up to 44 d. We combined biomarker responses into an integrate biomarker index which positively correlated with the Hg concentrations measured in the postmitochondrial fraction of the earthworm muscle, and with the available Hg fraction in soil. Current results suggest that glutathione redox cycle can be a complementary tool in the exposure and effect assessment of Hg-polluted soils., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Experimental work was carried out under close-to-real conditions to study mercury uptake by Hordeum vulgare L. cultivated in lysimeter experiments. The soil in the lysimeter experiment was obtained from a test plot located near Almadén (Spain) and had a mean mercury content of 22.9 mg kg(-1). A sequence of four crops was sown starting in autumn 2000 and repeated on a yearly basis until 2004. The first crop was grown in the field prior to the extraction of 5 one-cubic-meter lysimeters. The succeeding crops were sown in the lysimeter experiments at the CIEMAT Research Centre (Madrid, Spain). Samples of root and shoot were obtained during the four seasons. Concentrations of mercury at plant maturity in roots vary between I and 3 mg kg(-1) and in straw and grain the concentrations range from 72 to 480 microg kg(-1) and from 5 to 257 microg kg(-1), respectively. In order to assess the potential risk for human health and animal feed, an evaluation of the mercury content in the edible part of the crop has been carried out. According to legislation, there is no human health intoxication risk with a balanced consumption; otherwise, the forage use would have to be controlled.

Triatoma dimidiata is one of the main vectors of Chagas disease, and it has been shown to be a species complex. In the Yucatán peninsula, Mexico, vector populations are non-domiciliated, and the transmission of Trypanosoma cruzi thus critically relies on vector dispersal. This leads us to study the morphologic variations in T. dimidiata wings with respect to genetic factors (sex and genotype at the ITS-2 locus), geographic location, and T. cruzi-infection status. Females were found to have larger and more symmetrical wings than males. Wing shape was influenced by ITS-2 genotypes, although differences are unlikely sufficient to allow taxonomic discrimination of the sibling species. Hybrids were shown to have similar fluctuating asymmetries in wing size and shape as parental species, but the level of asymmetry in shape varied slightly between villages. The two later findings are consistent with a high level of gene flow between parental species, and the high dispersal potential of these non-domiciliated vectors. More surprisingly, individuals infected with T. cruzi were found to have larger wings than non-infected ones. This effect, which was consistently observed across sexes, genotypes and villages, is likely to be due to a direct impact of T. cruzi on insect development. Sex and infection status are thus likely to be key factors influencing vector dispersal with important impacts on disease transmission, since dispersal directly controls the domestic abundance of these vectors. These aspects should be investigated further to fully capture the ecology and evolution of Chagas disease transmission by non-domiciliated vectors., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Dirofilariasis (Dirofilaria immitis) and American trypanosomiasis (Trypanosoma cruzi) are zoonotic parasitic diseases affecting the hearts of a variety of mammalian host species, including dogs. In this study, some of the immunopathological characteristics of natural co-infection by these two parasites were compared with T. cruzi infection in dogs from Mexico. Antibody analysis in serum indicated significantly lower anti-T. cruzi IgG levels in co-infected dogs (n = 4) compared to those with T. cruzi infection alone (n = 9), together with a somewhat lower IgG2/IgG1 ratio. Cardiac tissue inflammation was limited and focal in co-infected animals whereas T. cruzi infected dogs had extensive and diffuse tissue inflammation. Three out of nine T. cruzi infected dogs and 1/4 of T. cruzi and D. immitis co-infected dogs showed cardiac alterations. The results showed that co-infections may interfere with host responses, and their significant prevalence (4/13 T. cruzi infected dogs) suggests that they should be taken into account by researchers and clinicians., (Copyright © 2009 Elsevier Ltd. All rights reserved.)

Chagas disease is a major public health problem, with about 10 million infected people, and DNA vaccines are a promising alternative for the control of Trypanosoma cruzi, the causing agent of the disease. We tested here a new DNA vaccine encoding a combination of two leading parasite antigens, TSA-1 and Tc24, for the prevention and therapy of T. cruzi infection. Immunized Balb/c mice challenged by T. cruzi presented a significantly lower parasitemia and inflammatory cell density in the heart compared to control mice. Similarly, the therapeutic administration of the DNA vaccine was able to significantly reduce the parasitemia and inflammatory reaction in acutely infected Balb/c and C57BL/6 mice, and reduced cardiac tissue inflammation in chronically infected ICR mice. Therapeutic vaccination induced a marked increase in parasite-specific IFNγ producing CD4(+) and CD8(+) T cells in the spleen as well as an increase in CD4(+) and CD8(+) T cells in the infected cardiac tissue. In addition, some effect of the DNA vaccine could still be observed in CD4-knockout C57BL/6 mice, which presented a lower parasitemia and inflammatory cell density, but not in CD8-deficient mice, in which the vaccine had no effect. These results indicate that the activation of CD8(+) T cells plays a major role in the control of the infection by the therapeutic DNA vaccine, and to a somewhat lesser extent CD4(+) T cells. This observation opens interesting perspectives for the potentiation of this DNA vaccine candidate by including additional CD8(+) T cell antigens/epitopes in future vaccine formulations., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

This study examined the ability of the white lupin to remove mercury (Hg) from a hydroponic system (Hg concentrations 0, 1.25, 2.5, 5 and 10 micromol/L) and from soil in pots and lysimeters (total Hg concentration (19.2 +/- 1.9) mg/kg availability 0.07%, and (28.9 +/- 0.4) mg/kg availability 0.09%, respectively), and investigated the accumulation and distribution of Hg in different parts of the plant. White lupin roots efficiently took up Hg, but its translocation to the harvestable parts of the plant was low. The Hg concentration in the seeds posed no risk to human health according to the recommendations of the World Health Organization, but the shoots should not be used as fodder for livestock, at least when unmixed with other fodder crops. The accumulation of Hg in the hydroponically-grown plants was linear over the concentration range tested. The amount of Hg retained in the roots, relative to the shoots, was almost constant irrespective of Hg dose (90%). In the soil experiments, Hg accumulation increased with exposure time and was the greater in the lysimeter than in the pot experiments. Although Hg removal was the greater in the hydroponic system, revealing the potential of the white lupin to extract Hg, bioaccumulation was the greatest in the lysimeter-grown plants; the latter system more likely reflects the true behaviour of white lupin in the field when Hg availability is a factor that limits Hg removal. The present results suggest that the white lupin could be used in long-term soil reclamation strategies that include the goal of profitable land use in Hg-polluted areas.

Chagas disease is a major vector-borne disease, and regional initiatives based on insecticide spraying have successfully controlled domiciliated vectors in many regions. Non-domiciliated vectors remain responsible for a significant transmission risk, and their control is a challenge. We performed a proof-of-concept field trial to test alternative strategies in rural Yucatan, Mexico. Follow-up of house infestation for two seasons following the interventions confirmed that insecticide spraying should be performed annually for the effective control of Triatoma dimidiata; however, it also confirmed that insect screens or long-lasting impregnated curtains may represent good alternative strategies for the sustained control of these vectors. Ecosystemic peridomicile management would be an excellent complementary strategy to improve the cost-effectiveness of interventions. Because these strategies would also be effective against other vector-borne diseases, such as malaria or dengue, they could be integrated within a multi-disease control program.

Objective: Chagas disease is a major vector-borne parasitic disease in Latin America, primarily transmitted to humans by triatomine vectors. Non-domiciliated triatomine species such as Triatoma dimidiata in the Yucatan peninsula, Mexico, can transiently invade houses and are emerging as a major challenge to control Trypanosoma cruzi transmission to humans. We analyzed the spatio-temporal spreading of house infestation by T. dimidiata in four rural villages., Methods: Triatomines were collected in four rural villages over a 2 years period, and the spatio-temporal patterns of infestation were analyzed., Results: Triatomines were consistently more abundant at the periphery of villages than in centers, indicating a much higher risk of T. cruzi transmission at the periphery. Male T. dimidiata were found further in the center of the village, while females remained closer to the periphery, suggesting differential dispersal capabilities between sexes, although the timing of dispersal appeared identical. Surprisingly, infected females were consistently collected in houses much further from the surrounding bushes than non-infected females, while the distribution of males was unaffected by their T. cruzi infection status, suggesting an increased dispersal capability in infected females., Conclusion: The spatial structure of infestation should be taken into account for the prioritization of vector control activities within villages, and spatially targeted interventions may be explored. A potential vector manipulation by T. cruzi, observed for the first time in triatomines, may favor parasite transmission to new hosts.

Triatoma dimidiata is one of the major Chagas disease vectors, with an extensive diversity in its morphology, habitat, and level of domiciliation. Molecular studies based on the internal transcribed spacer 2 (ITS-2) have subdivided this species into four potential taxonomic groups. Using both ITS-2 and cytochrome B markers, we confirmed the sibling species status of ITS-2 Group 3 and detected an apparent sympatry of ITS-2 Groups 2 and 3 in the Yucatan peninsula, Mexico. Here we examine the geographic distribution of T. dimidiata ITS-2 genotypes in the region and compare their egg production and Trypanosoma cruzi infection rates, as indicators of biological differences between groups. PCR genotyping of large natural populations showed an extensive sympatry of Groups 2 and 3 in most of the peninsula, often within the same house. We also detected a large proportion of individuals displaying ITS-2 sequences from both Groups 2 and 3, suggesting hybridization. Analysis of ITS-2 genotype frequencies indicated a strong departure from Hardy-Weinberg equilibrium in female hybrids, but not in males, due to a large heterozygote deficit. These results suggest random mating between ITS-2 Groups 2 and 3 combined with reduced viability and/or survival in female hybrids. This and other factors may allow for the maintenance of distinct ITS-2 Groups 2 and 3 populations despite high hybrid frequencies. Importantly, T. cruzi infection was much higher in hybrids compared to ITS-2 Groups 2 and 3 individuals, but all three genotypes appeared to seasonally infest houses in a similar manner in the region. These findings warrant further studies on T. dimidiata taxonomy and its epidemiologic implications.

The present study aims to assess the impact of the Spanish young offenders law (LO/2000). Recidivism and its associated risk factors were used as indicators of impact. Data were collected from young offenders' reports opened after 2001 and closed before 2005. The final sample consisted of 382 young offenders (327 males and 55 females). Results indicated that 70% had not re-offended in an average period of 1.6 years. Most of the youngsters with fewer risk factors, usually start their criminal careers with less serious offences and the interventions seemed to be fairly effective. In the cases of young offenders with a higher number of risk factors, the interventions (custodial and non-custodial) were less effective, as recidivism rates were higher. Interventions must focus on family and community contexts in order to achieve adequate social integration of young delinquents.

This work studies mercury root uptake by Lavandula stoechas var. Kew Red (lavender) and the distribution of this metal through the plant under greenhouse conditions along three consecutive seasons. Mercury concentration in plant tissues and in the different products obtained from lavender plants (essential oil, toilet water and in lavender tea) was assessed in order to evaluate the possible cultivation of lavender as a profitable alternative land use to mercury mining in the Almadén area once the mine had been closed down. Mercury concentration in useful parts of the plant was low (0.03-0.55 mg kg(-1)). Likewise, the essential oil, toilet water and tea obtained from these plants presented very low mercury levels, below the detection limit of the used equipment (<0.5 microg kg(-1)). In the case of the obtained tea, according to the recommendations given by the World Health Organization, the maximum daily intake of it without intoxication risk would be 85.2l. So, although other sources of mercury intake should also be considered in order to elaborate a complete toxicological risk assessment. Lavender data, obtained under this greenhouse working conditions, shows that lavender cultivation could be an alternative crop in the Almadén area.

Leishmaniasis is a group of diseases caused by protozoan parasites of the Leishmania genus. Previous studies have shown that a DNA vaccine encoding Leishmania donovani antigen nucleoside hydrolase 36 and L. mexicana glycoprotein 63 is protective in mice. We investigated here the efficacy of this DNA vaccine to induce protection in golden hamsters. Male hamsters were more susceptible to infection by Leishmania mexicana than females. Following immunization with two doses of the DNA vaccine, only females resulted protected while males developed normal lesions.

Chagas' disease is a major public health concern in most Latin American countries and its prevention is based on insect vector control. Previous work showed that in the Yucatan peninsula of Mexico, houses are transiently infested by adult Triatoma dimidiata, which then fail to establish sustained colonies. The present study was designed to evaluate the seasonality and possible causes of the dispersal of sylvatic T. dimidiata toward the houses and the subsequent failure of colonization. Dispersal was highly seasonal and correlated with temperature, pressure, and wind speed. Analysis of sex ratio, feeding status, and fecundity of sylvatic populations of T. dimidiata indicated a rather low feeding status and low potential fecundity, suggesting that seasonal dispersal may be associated with foraging for better conditions. Also, feeding status and potential fecundity tended to improve in the domestic habitat but remained largely suboptimal, suggesting that these factors may contribute to the ineffective colonization of this habitat.

The control of wild triatomine populations that can invade dwellings is a major challenge for Chagas disease control in Mexico, but a better knowledge of the biology of these populations is required to develop appropriate control methods. We describe a new terrestrial ecotope of Triatoma longipennis, a principal vector in the occidental part of Mexico, in addition to its previously identified niche in rock pile boundary walls. Analysis of feeding hosts in the two ecotopes showed that this species is able to diversify its food sources outside of the principal hosts, Dasypus novemcinctus and Procyon lotor, and to disperse in search of new meals. Moreover, T. longipennis are strongly infected not only by the Trypanosoma cruzi I lineage found in the domestic cycle, but also by T. cruzi lineage II. The impact of T. cruzi II on human infection remains to be determined.

Chagas disease is caused by Trypanosoma cruzi and dogs are an important reservoir of the parasite as well as a good model for the study of the pathogenesis of the disease. We aimed here at characterizing the immunopathology of naturally infected dogs in Merida, Yucatan, Mexico. Following an initial screening for T. cruzi seropositive stray dogs, we examined 9 seropositive and 10 seronegative animals. High lymphocytes and low monocytes counts were observed in peripheral blood from seropositives dogs. Three of nine seropositive dogs presented electrocardiographic alterations including right bundle branch block, sinusal block and QRS complex alterations and some right ventricle enlargement was noted. Histopathologic analysis of cardiac walls revealed significant inflammation with a clear tropism for the right ventricle, although most walls were affected. Seropositive dogs presented low IgG1 and high IgG2 levels. Higher IgG1 levels were associated with increased cardiac index and myocarditis, suggesting that a Th2 immune response leads to susceptibility and increased disease severity. These observations shed some light on the mechanisms of pathogenesis of Chagas disease in dogs, and provide a good framework for the evaluation of novel drugs and vaccines in this animal model.

The incidence of Clostridium difficile infection in North America and Europe has increased in the last years, generating concern among health professionals. A new strain of C. difficile has been identified in recent nosocomial outbreaks and community-acquired infections. This new strain, characterized as toxigenic type III, PCR ribotype 027 (C. difficile 027), presents higher pathogenicity because of increased exotoxin production, and a characteristic antibiotic resistance profile. Since 2003, several European countries have notified cases of C. difficile 027-associated disease, a fact that demonstrates its rapid dissemination. In this article, we review the latest nosocomial outbreaks associated with this new strain, which illustrate the need for a standardized surveillance system for early detection and implementation of control measures aimed at reducing the spread of this microorganism.

The irregular presence and low abundance of wild triatomines inside domiciles make their detection more difficult than that of domiciled species, so that vector surveillance and evaluation of Chagas disease transmission risk are more challenging. We compared timed manual searches, considered as the gold standard, with community-based collections, for their efficacy at monitoring domestic and peridomestic infestation by non-domiciliated Triatoma dimidiata, and community-based collection was the most sensitive and cost effective. Scaling up community participation permitted investigation of fine temporal variations in infestation by T. dimidiata in over 700 houses. We confirmed a large seasonal infestation during March-July, but weekly and daily collections showed a rather stochastic pattern of bug presence in the houses, even during this period. These data are of key importance for the successful implementation of vector control, and community participation is a method of choice for sustained monitoring of infestation by non-domesticated triatomines.

Leishmaniasis is a neglected disease with an estimated 12 million infected people. The recent completion of the sequencing of the Leishmania major genome has opened opportunities for the identification of targets for vaccine development. We present here the first attempt at identifying novel vaccine candidates by whole genome analysis. We predicted CD8(+) T cell epitopes from the L. major proteome and validated in vivo in mice the immunogenicity of some of the best predicted epitopes. Consensus epitope predictions from 8272 annotated protein sequences with 5-8 different algorithms allowed the identification of 78 class I CD8(+) epitopes. BALB/c mice were immunized with 26 synthetic peptides corresponding to the most likely epitopes. Fourteen (54%) resulted immunogenic, with eight being strong inducers of T cell IFNgamma production. None of the proteins from which the epitopes are derived are differentially expressed, only two may be surface proteins, eight have putative enzymatic, and metabolic activities. These epitopes and proteins represent new antigen candidates for further studies. While pathogen genomes have not yet delivered their full promise in terms of human health applications, our study opens the way for extensive genome mining for antigen identification and vaccine development against Leishmania and other pathogens.

Chagas disease is a major public health problem from South America to Mexico, with approximately 10 million infected people. Chagas disease is known to occur in Belize, but little is known about the prevalence of Trypansoma cruzi infection in the Belizean population or the Chagas vector in this region. An entomologic survey of triatomines in the central and southern region of Belize was thus performed. Triatomines were collected by community participation in 37 villages of the Cayo (central) and Toledo (southern) districts and analyzed for infection with T. cruzi by microscopic examination and polymerase chain reaction. Two hundred fifty-six triatomines were collected in 34/37 villages, indicating a wide distribution, and all were identified as T. dimidiata. The majority (87%) were adults (42% males, 58% females), and 13% were larval stages. The infection rate with T. cruzi was 28%. Triatomines were more abundant during the hot season (March-July) compared with the cooler season (September-February). These results confirm that there is a significant risk for autochthonous Chagas disease transmission in central and southern Belize and suggest a pattern of seasonal infestation by nondomiciliated adult triatomines, which are likely to be closely related to T. dimidiata from Yucatan, Mexico. Further entomologic and epidemiologic studies should be performed to precisely determine T. cruzi transmission risk to humans, as well as the seroprevalence of T. cruzi infection and incidence of Chagasic cardiomyopathy in the Belizean population.

Chagas' disease is an important health problem in most Latin American countries, and a concern in dog populations, which act as a reservoir. We showed in previous studies that a therapeutic DNA vaccine could partially control the pathology after Trypanosoma cruzi infection in mice, and this vaccine may represent an alternative treatment for Chagas' disease. Here we evaluated the therapeutic efficacy of this vaccine in experimentally infected dogs for up to 2 months after infection. Our results suggest that DNA vaccine treatment may affect the immune response and delay Chagas' disease progression in T. cruzi-infected dogs, and confirm the potential of this novel treatment.

Solanum melongena L. (eggplant) is a native culture from India, found throughout the world, and is one of the most popular vegetables in the Mediterranean area. This work evaluates the potential use of eggplant as an economic alternative in an area with high mercury background concentrations. This implies the study of several factors such as the mercury absorption capacity of eggplant and the capacity of the soil for agricultural use. The research work has been carried out using soil from the mercury mining district of Almadén (Spain), where total mercury concentration was on average 14.16+/-0.65mgkg(-1). In this area, eggplant is a typical crop that is widely used for human consumption. The experimental work was performed in pots under greenhouse conditions. Three samplings were performed during the entire cultivation cycle. Mercury concentration was determined in the different plant organs, where the highest concentration was located in the root system. The results obtained show that the consumption of eggplant, growing under these controlled conditions, does not suppose a risk for human health according to the recommendations of the World Health Organization.

The observation of widespread seasonal infestation by Triatoma dimidiata in rural villages around the city of Mérida, Yucatán, México, led us to reconsider the presence of Chagas disease vectors and the risk factors for house infestation in the city itself. Bugs were collected in 150 houses from 30 neighborhoods distributed throughout the city. We observed a widespread infestation by T. dimidiata in the city, with 38% of infested houses and 48% of the collected triatomines testing positive for Trypanosoma cruzi. House infestation by triatomines was greatest during the months of April-June. Infestation risk factors were related with backyard characteristics rather than housing type and quality of housing: houses located in the periphery of the city, with abandoned lots on the sides and large backyards, had a higher risk of being infested, while those with mosquito screens and occasional insecticide spraying in their yards had a lower risk. Several human blood meals were also identified and seropositive patients were distributed through most of the city, confirming the potential for urban transmission of Chagas disease to humans. This study shows that urban Chagas disease should not be neglected and surveillance programs should be implemented to further evaluate the magnitude of the problem.

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is a major public health problem in most of Latin America. A key priority is the development of new treatments, due to the poor efficacy of current ones. We report here the comparative evaluation of therapeutic DNA vaccines encoding various T. cruzi antigens. ICR mice infected with 500 parasites intraperitoneally were treated at 5 and 12 days postinfection with 20 microg of plasmid DNA encoding T. cruzi antigens TSA-1, TS, ASP-2-like, Tc52 or Tc24. Treatment with plasmid encoding TS and/or ASP-2-like antigens had no significant effect on parasitemia or survival. Treatment with Tc52 DNA significantly reduced parasitemia, as well as cardiac parasite burden, and improved survival, although myocarditis was not significantly affected. Finally, treatment with plasmids encoding Tc24 and TSA-1 induced the most complete control of disease as evidenced by significant reductions in parasitemia, mortality, myocarditis and heart parasite burden. These data demonstrate that therapeutic vaccine efficacy is dependent on the antigen and suggest that DNA vaccines encoding Tc24, TSA-1, and Tc52 represent the best candidates for further studies of a therapeutic vaccine against Chagas disease.

The approach developed by Fuhrer in 1995 to estimate wheat yield losses induced by ozone and modulated by the soil water content (SWC) was applied to the data on Catalonian wheat yields. The aim of our work was to apply this approach and adjust it to Mediterranean environmental conditions by means of the necessary corrections. The main objective pursued was to prove the importance of soil water availability in the estimation of relative wheat yield losses as a factor that modifies the effects of tropospheric ozone on wheat, and to develop the algorithms required for the estimation of relative yield losses, adapted to the Mediterranean environmental conditions. The results show that this is an easy way to estimate relative yield losses just using meteorological data, without using ozone fluxes, which are much more difficult to calculate. Soil water availability is very important as a modulating factor of the effects of ozone on wheat; when soil water availability decreases, almost twice the amount of accumulated exposure to ozone is required to induce the same percentage of yield loss as in years when soil water availability is high.

In the Yucatán Peninsula of Mexico, the main vector of Chagas disease is Triatoma dimidiata. Field studies suggest that natural transmission occurs through transient and seasonal invasion of houses by sylvatic/peridomestic triatomines, rather than through persistent domiciliated bug populations. We investigated the genetic structure of T. dimidiata populations, using morphometry and microsatellite markers, to assess dispersal of individuals in this triatomine species and to understand the dynamics of domestic infestation. We observed low phenotypic and genetic differentiation among populations from different villages, with an FST of only 0.0553, which suggested a weak but significant population structure at this level. Similarly low but significant differences were observed among populations from the same village but different biotopes (sylvatic, peridomestic, and domestic), with FST values ranging from 0.0096 to 0.0455. These data suggested elevated dispersal of bugs between biotopes (Nm = 5-25), which was confirmed by likelihood and Bayesian assignment tests. A proportion of bugs collected within domiciles were significantly assigned to peridomestic and sylvatic areas. This study showed that T. dimidiata has important dispersal capabilities that can explain the seasonal pattern of domicile infestation by peridomestic and sylvatic bugs. Therefore, dispersal should be taken into account in the design of effective vector control strategies.

The Almadén area is an exceptional case of mercury concentration in the world, where cinnabar is the predominant mineralised form. Mining activities have been carried out over the past two thousand years and once this activity is concluded, a restoration of the environment is necessary for the affected areas. That implies the selection, optimisation and application of the most appropriate techniques focused on the recovery of contaminated areas. Phytotechnology is one of the proposed techniques, which considers the use of plants due to the low environmental impact and their proved efficiency. In this framework, it is necessary to study the behaviour of mercury in the soil-plant system and to determine the mercury absorption capacity of the different Almadén plant species. Therefore, field and laboratory studies have been carried out to determine the easily available forms of mercury in ten test plots in the Almadén area and the resulting data is related to the mercury accumulation in different plant species of the studied territory. Special attention is given to the easily available forms of mercury in the analysed soils and used as the transfer factor for the Hg-availability index that relates the amount of mercury in a plant with the total amount of mercury in a soil and with the easily available forms. The result of this experimental work is selecting the plant species suitable to be used in a future implementation of phytotechnologies in this area.

Previous work showed that immunotherapy with a DNA vaccine encoding Trypanosoma cruzi antigen TSA-1 reduced cardiac tissue damage and improved survival in mice when administered during the acute or chronic phases of T. cruzi infection. In the present study, we investigated changes in T-cell populations induced by DNA vaccine immunotherapy. ICR mice were infected with 500 T. cruzi blood trypomastigotes and treated during the acute or chronic phases with two 100 microg doses of DNA vaccine. Analysis of stained splenocytes by flow cytometry indicated that the therapeutic vaccine induced a rapid increase in the number of CD4+ and CD8+ T cells in both the acute and chronic phases. Also, there was a rapid increase in T. cruzi-specific IFNgamma-producing CD8+ T cells following treatment during the chronic phase. The effects of these changes on the control of infection required longer time periods to be detectable but resulted in a reduction in myocarditis and T. cruzi parasite burden in both phases of the infection, as assessed by histopathologic analysis and semi-quantitative PCR detection of T. cruzi in cardiac tissue. These results suggest that DNA vaccines that induce CD8+ T-cells activity and IFNgamma production, would be good candidates for effective therapeutic vaccination against T. cruzi infection.

Hurricanes can have devastating effects on health and may directly modulate vector-borne diseases. Chagas disease is a zoonosis caused by the protozoan parasite Trypanosoma cruzi and transmitted by triatomine bugs, and the effect of hurricanes on these bugs is largely unknown. We thus performed a detailed study of the changes in Triatoma dimidiata geographic distribution and infection rates after Hurricane Isidore devastated the Yucatán Peninsula in September 2002. Bugs were collected in 34 villages from the entire peninsula, during a year, starting 3 months after the hurricane. Pre- and posthurricane bug collections were compared to assess changes. The most notable effect was a large increase in domestic abundance of T. dimidiata during the 6 months after the hurricane. This increase was maximum along the path of the hurricane. These results suggest that vector control programs should be implemented along the path of hurricanes to prevent an increase in Chagas disease transmission risk in the ensuing months.

Objective: To deep in the knowledge of the involvement of G-protein alphas and alphai subunits in human prostate cancer., Methods: Prostate tissue from 9 patients undergoing radical prostatectomy for prostate cancer and 5 controls undergoing cystoprostatectomy for bladder carcinoma. G-protein alphas and alphai subunits were studied for expression (mRNA by RT-PCR and protein by Western-blot), functionality (adenylyl cyclase activity, AC) and possibility of mutations (analysis with restriction enzymes and cDNA sequentiation)., Results: At mRNA level, the expression of alphas, alphai1, alphai2 y alphai3 was detected in healthy and cancerous tissues. At protein level, the expression of alphas y alphai1,2 diminished (25% and 40%, respectively) in prostate cancer. The expression of alphai3/0 also diminished, whereas that of beta subunit was not modified. Basal AC activity in adenocarcinoma membranes was 40% inferior to the control. Digestion with restriction enzymes Eag I or AlwN I did not allow to locate mutations in alphas. However, digestion at alphai2 level with BstU I enzyme served to observe a change of Gln205 (CAG triplet) to Pro (CCG)., Conclusions: The functionality and expression of heterotrimeric G proteins are selectively modified in human prostate adenocarcinoma, occurring in addition some punctual mutation. The observed substitution of Gln205 by Pro may result in a low GTPase activity for alphai2 that, therefore, is stabilized in its active form.

Outbreaks of human respiratory syncytial virus (HRSV) are the leading cause of serious acute lower respiratory viral disease in many countries in different continents. Data on clinical and epidemiological aspects of HRSV infections in this country have been reported, but there is lack of data regarding the molecular epidemiology of this virus in Salvador. The genetic variability of HRSV isolated during an outbreak in Salvador, Brazil (1999) has been analysed. Partial sequences of the G protein gene of 13 isolates from antigenic group A and 4 isolates from antigenic group B of HRSV were determined. Nucleotide sequences of C-terminal G gene were compared to sequences of HRSV isolates from countries of South America and from the rest of the world available at the GenBank. Brazilian group A and B isolates were clustered into previously characterised genotypes: GA5, GA2, GA7, and GB3, SAB3, respectively. This is the first study of GA7 and SAB3 genotypes circulation in South American countries. It is interesting to point out that viruses isolated in Salvador appear to be closer related with those from Montevideo-Uruguay and Buenos Aires, Argentina strains, suggesting circulation of similar strains among different South American countries in different seasons. Moreover, viruses closely related genetically circulated in the same year in Salvador and distant places such as Mozambique, supporting the previous suggestion on the complexity of HRSV strain circulation patterns, and the high capability of HRSV spreading world-wide.

In most countries, Chagas disease transmission control remains based on domestic insecticide application. We thus evaluated the efficacy of intra-domicile cyfluthrin spraying for the control of Triatoma dimidiata, the only Chagas disease vector in the Yucatán peninsula, Mexico, and monitored potential re-infestation every 15 days for up to 9 months. We found that there was a re-infestation of houses by adult bugs starting 4 months after insecticide application, possibly from sylvatic/peridomicile areas. This points out the need to take into account the potential dispersal of sylvatic/peridomestic adult bugs into the domiciles as well as continuity action for an effective vector control.

The mechanisms involved in the pathology of chronic chagasic cardiomyopathy are still debated, and the controversy has interfered with the development of new treatments and vaccines. Because of the potential of DNA vaccines for immunotherapy of chronic and infectious diseases, we tested if DNA vaccines could control an ongoing Trypanosoma cruzi infection. BALB/c mice were infected with a lethal dose (5 x 10(4) parasites) as a model of acute infection, and then they were treated with two injections of 100 microg of plasmid DNA 1 week apart, beginning on day 5 postinfection. Control mice had high levels of parasitemia and mortality and severe cardiac inflammation, while mice treated with plasmid DNA encoding trypomastigote surface antigen 1 or Tc24 had reduced parasitemia and mild cardiac inflammation and >70% survived the infection. The efficacy of the immunotherapy also was significant when it was delayed until days 10 and 15 after infection. Parasitological analysis of cardiac tissue of surviving mice indicated that most mice still contained detectable parasite kinetoplast DNA but fewer mice contained live parasites, suggesting that there was efficient but not complete parasite elimination. DNA vaccine immunotherapy was also evaluated in CD1 mice infected with a low dose (5 x 10(2) parasites) as a model of chronic infection. Immunotherapy was initiated on day 70 postinfection and resulted in improved survival and reduced cardiac tissue inflammation. These results suggest that DNA vaccines have strong potential for the immunotherapy of T. cruzi infection and may provide new alternatives for the control of Chagas' disease.

The antigenic and genetic diversity of G glycoprotein from 25 human respiratory viruses (group A) isolated during nine consecutive epidemics (1993-2001) in Montevideo, Uruguay, and 7 strains isolated in Buenos Aires, Argentina, in the same period were analyzed. Genetic variability was evaluated by partial sequence of the G protein gene. Phylogenetic analysis indicated that most Uruguayan and Argentinean group A isolates clustered into three genotypes: GA5, GA2, and GA1. Some strains clustered into the GA3 genotype characterized previously. The antigenic analysis was carried out with a panel of anti-G monoclonal antibodies that recognized conserved and strain-specific epitopes. A close correlation between the antigenic and genetic relatedness of the strains analyzed was observed., (Copyright 2003 Wiley-Liss, Inc.)

Group A rotavirus infections were detected in 93 of 410 fecal samples from children with acute diarrhea, admitted in three main hospitals of Asunción, Paraguay, from August 1998 to August 2000. Most of the rotavirus-infected patients were admitted during the winter season in the three epidemic years. The rotavirus infection rate was highest in infants from 6 to 23 months of age. In the 93 samples examined, 10 different rotavirus electropherotypes were recognized, but two of them largely predominated. Only one sample showed a short electropherotype pattern, thus indicating a minor involvement of the rotavirus subgroup I in rotaviral acute diarrhea in the area and the time during which the survey was carried out.

Chagas disease represents a major public health concern in most of Latin America, and its control is currently based on vector control and blood bank screening. We investigated the geographic distribution and seasonal variations in triatomine populations in the Yucatan peninsula of Mexico to obtain entomologic data for the optimization of potential control programs. We collected domiciliated and peri-domiciliated Triatoma dimidiata from 115 houses in 23 villages distributed throughout most of the peninsula. A high abundance of bugs was observed in the northern part of the peninsula, indicating a prioritary area for vector control. Part of this distribution could be attributed to the type of vegetation. We also documented strong seasonal variations in T. dimidiata populations, with a higher abundance during the hot and dry season in April-June. These variations, associated with reduced year-round colonization of houses and the analysis of developmental stage structure, suggest that flying adults seasonally invading houses may play a larger role than domiciliated bugs in transmission of Trypanosoma cruzi to humans. The importance of this transmission dynamics may not be limited to the Yucatan peninsula, but may be a general mechanism contributing to natural transmission that should be taken into account in other regions for the design and optimization of control strategies.

Electropherotypes of human rotavirus isolates from infants with acute diarrhea belonging to two populations with different clinical features were determined. Thirteen electropherotypes were identified in total 69 isolates; 46 (66.6%) isolates had long RNA migration patterns and 23 (33.3%) isolates had short migration pattern. One of the long-pattern electropherotypes (47.82% of the total electropherotypes) was predominant. It was detected in both populations almost throughout the whole period of the study, while other electropherotypes were found only occasionally. The co-circulation of long and short electropherotypes was not frequent.

Background: To assess the prevalence of orthostatic hypotension (OH) in an elderly population and to evaluate the influence of hypertension control and of the type of antihypertensive drug used., Methods: 2,700 elderly patients (> 65 years) from the EPICARDIAN study were included. Blood pressure (BP) was measured twice with the patient seated and once again 1 to 3 minutes afterwards with the patient standing. Hypertension is defined as BP > or = 140/90 mmHg or if the patient received antihypertensive treatment. Orthostatic hypotension was defined as a fall of SBP > or = 20 mmHg and/or DBP > or = 10 mmHg 1 to 3 minutes after the postural change., Results: 71.6% of the patients were classified as hypertensive and 57.1% were receiving pharmacological treatment. The overall prevalence of OH was 6.8% among hypertensive patients, 8.1% and 3.4% in normotensives patients (p < 0.05). No significant difference was found in the prevalence of OH between those receiving (7.7%) or not (8.6%) antihypertensive medication. No association was found either between the prevalence of OH and the type or number of antihypertensive drugs used. 17.6% of the patients reached hypertension optimal control (SBP < 140 and DBP < 90 mmHg), the prevalence of OH in these patients was 5.3%, among the uncontrolled the prevalence was 8.9% (p < 0.05). The adjusted OR was 1.91 (1.1-3.3) for the prevalence of OH in the uncontrolled patients versus the controlled., Conclusions: The prevalence of OH in the elderly is not very high, being greater among hypertensive than normotensive patients. No association was found between the prevalence of OH and the number of drugs received. Reaching hypertension control reduces the prevalence of OH.

Leishmaniases represent an important public health problem in large parts of the world. In the south-east of Mexico, the major species isolated from patients is Leishmania mexicana mexicana, causing localised cutaneous leishmaniasis, and the development of a vaccine is a key objective for the control of this parasite. We thus performed a comparative study of DNA vaccines encoding L. m. mexicana gp63 and CPb, L. m. amazonensis gp46, and L. major LACK to define the best antigen(s) candidate(s). cDNAs encoding these antigens were subcloned into the VR1012 plasmid, and susceptible BALB/c mice were immunised with two i.m. injections of 100 microg of plasmid DNA. All mice immunised with VR1012-GP46, VR1012-CPb and VR1012-GP63 showed increased IgG levels against L. m. mexicana, but not those immunised with VR1012-LACK. Two to three weeks after the last immunisation, mice were challenged by the injection of 4 x 10(6) L. m. mexicana parasites in the foot pad to evaluate protection. Measurement of lesion size indicated that mice immunised with VR012-GP46, VR012-GP63 and VR1012-CPb were partially protected against infection, whereas the other plasmids had no effect. Thus, these plasmids represent good candidates for further development of DNA immunisation against L. m. mexicana.

Study Objective: This study describes mortality due to cerebrovascular disease (CVD) in Spain, based on time-series analysis in the period 1951-1995 by age, sex, and cohort of birth; spatial distribution observed for the five-year period 1991 1995, and time-spatial analysis in the period 1992-1995 vs. 1988-1991. Special attention is paid to risk of medium aged population., Design: Longitudinal and cross-sectional observational study., Setting and Participants: Spanish population. All mortality data used were taken from official statistics. Time trends and spatial distribution were analyzed using log-linear Poisson regression models., Main Results: CVD mortality declined over the last two decades of the study period (1974-1995) by an annual average of 4.16% (95% CI: 3.95-4.36) and 4.00% (95% CI: 3.77-4.24) in men and women, respectively. The downward trends were accelerated in last decade. An excess of male mortality was in evidence. For all age groups mortality declined with more recent cohorts, but the decline was less marked among ages 35 64. Spatial distribution of CVD mortality revealed a north-south pattern, but this is being difuminated by increasing rates in the lower risk provinces. Internationally, Spain ranks midway to low in terms of its overall CVD mortality., Conclusions: Efforts to reduce CVD incidence and case fatality are the essential prerequisite for any long-term improvement in mortality. Accordingly, further research is called for into current disease morbidity and the risk factors to be targeted at a general population level, nationwide.

Hypereosinophilic syndromes are characterized by very high levels of eosinophils in peripheral blood and a dysfunction of several organs as a consequence of their massive infiltration by eosinophilic cells. Cardiac alterations are traditionally known as fibroplastic endomyocarditis (Loeffler's Syndrome). We present the case of a female patient admitted in another center for the study of an accidentally discovered eosinophilia and referred to us because of her progressive hemodynamic deterioration followed by a poor clinical evolution. The anatomopathologic findings showed the classical injuries of this Syndrome; specially at cardiac level, where it is important to highlight the occupation of all the right ventricule's cavity by a clog. These injuries justified the origin of the stormy clinical presentation.