Sustainability of vector control strategies in the Gran Chaco Region: current challenges and possible approaches

Sustainability has become a focal point of the international agenda. At the heart of its range of distribution in the Gran Chaco Region, the elimination of Triatoma infestans has failed, even in areas subject to intensive professional vector control efforts. Chagas disease control programs traditionally have been composed of two divorced entities: a vector control program in charge of routine field operations (bug detection and insecticide spraying) and a disease control program in charge of screening blood donors, diagnosis, etiologic treatment and providing medical care to chronic patients. The challenge of sustainable suppression of bug infestation and Trypanosoma cruzi transmission can be met through integrated disease management, in which vector control is combined with active case detection and treatment to increase impact, cost-effectiveness and public acceptance in resource-limited settings. Multi-stakeholder involvement may add sustainability and resilience to the surveillance system. Chagas vector control and disease management must remain a regional effort within the frame of sustainable development rather than being viewed exclusively as a matter of health pertinent to the health sector. Sustained and continuous coordination between governments, agencies, control programs, academia and the affected communities is critical.

Breeding sites of Culicoides pachymerus Lutz in the Magdalena River basin, Colombia

The breeding sites of Culicoides pachymerus are described for the first time in western Boyacá Province, Colombia, where this species is a public health problem. In addition to being a nuisance due to its enormous density and its high biting rates, C. pachymerus cause dermatological problems in the human population. Analysis of microhabitats by the sugar flotation technique and the use of emergence traps allowed us to recover 155 larvae of Culicoides spp and 65 adults of C. pachymerus from peridomiciliary muddy substrates formed by springs of water and constant rainwater accumulation. These important findings could aid in the design of integrated control meas-ures against this pest.

Isolation and characterization of microsatellite loci for the European tree frog (Hyla arborea)

We developed 11 new microsatellite markers for the European tree frog (Hyla arborea), and tested patterns of polymorphism in 54 adults (27 males and 27 females) from two ponds close to Lausanne (Western Switzerland). One marker was sex linked and two pairs displayed linkage disequilibrium. Comparisons of allele numbers with heterozygosity values support a stepwise-mutation model at neutral equilibrium, with mutation rates spanning nearly two orders of magnitude. These markers will prove useful for population genetic studies and fine-scale investigations requiring genetic assignment techniques.

The genetic consequences of hatchery-induced sperm competition in a salmonid

Supportive breeding is an important tool in conservation management, but its long-term genetic consequences are not well understood. Among the factors that could affect the genetics of the offspring is sperm competition as a consequence of mixed-milt fertilizations - which is still a common practice in many hatcheries. Here, we measured and combined the relevant factors to predict the genetic consequences of various kinds of hatchery-induced sperm competition. We drew a random sample of male Coregonus zugensis (an Alpine whitefish) from a hatchery program and quantified their in vitro sperm potency by integrating sperm velocity during the first minute after activation, and their in vitro milt potency by multiplying sperm potency with milt volume and sperm cell density. We found that not controlling for sperm density and/or milt volume would, at a constant population size, decrease the variance effective number of male breeders N-em by around 40-50%. This loss would decrease with increasing population growth rates. Partial multifactorial breeding and the separate rearing of in total 799 batches of eggs revealed that neither sperm nor milt potency was significantly linked to egg survival. Sperm and milt potency was also not significantly correlated to other potential quality measures such as breeding tubercles or condition factor. However, sperm potency was correlated to male age and milt potency to male growth rate. Our findings suggest that hatchery-induced sperm competition not only increases the loss of genetic variation but may also induce artificial selection, depending on the fertilization protocol. By not equalizing milt volume in multi-male fertilization hatchery managers lose relatively more genetic variation and give fast-growing males a reproductive advantage, while equalizing milt volume reduces the loss of genetic variation and favors younger males who may have fast sperm to compensate for their subdominance at the spawning place. (c) 2007 Elsevier Ltd. All rights reserved.

Experimental Modeling and Control Strategies on an Open Mobile Robot Platform PRIM

This research work deals with the problem of modeling and design of low level speed controller for the mobile robot PRIM. The main objective is to develop an effective educational tool. On one hand, the interests in using the open mobile platform PRIM consist in integrating several highly related subjects to the automatic control theory in an educational context, by embracing the subjects of communications, signal processing, sensor fusion and hardware design, amongst others. On the other hand, the idea is to implement useful navigation strategies such that the robot can be served as a mobile multimedia information point. It is in this context, when navigation strategies are oriented to goal achievement, that a local model predictive control is attained. Hence, such studies are presented as a very interesting control strategy in order to develop the future capabilities of the system

Schistosomiasis risk mapping in the state of Minas Gerais, Brazil, using a decision tree approach, remote sensing data and sociological indicators

Schistosomiasis mansoni is not just a physical disease, but is related to social and behavioural factors as well. Snails of the Biomphalaria genus are an intermediate host for Schistosoma mansoni and infect humans through water. The objective of this study is to classify the risk of schistosomiasis in the state of Minas Gerais (MG). We focus on socioeconomic and demographic features, basic sanitation features, the presence of accumulated water bodies, dense vegetation in the summer and winter seasons and related terrain characteristics. We draw on the decision tree approach to infection risk modelling and mapping. The model robustness was properly verified. The main variables that were selected by the procedure included the terrain's water accumulation capacity, temperature extremes and the Human Development Index. In addition, the model was used to generate two maps, one that included risk classification for the entire of MG and another that included classification errors. The resulting map was 62.9% accurate.

Decrease in beta-Cell Proliferation Precedes Apoptosis during Diabetes Development in Bio-Breeding/Worcester Rat: Beneficial Role of Exendin-4

In autoimmune type 1 diabetes mellitus, proinflammatory cytokine-mediated apoptosis of beta-cells has been considered to be the first event directly responsible for beta-cell mass reduction. In the Bio-Breeding (BB) rat, an in vivo model used in the study of autoimmune diabetes, beta-cell apoptosis is observed from 9 wk of age and takes place after an insulitis period that begins at an earlier age. Previous studies by our group have shown an antiproliferative effect of proinflammatory cytokines on cultured beta-cells in Wistar rats, an effect that was partially reversed by Exendin-4, an analogue of glucagon-like peptide-1. In the current study, the changes in beta-cell apoptosis and proliferation during insulitis stage were also determined in pancreatic tissue sections in normal and thymectomized BB rats, as well as in Wistar rats of 5, 7, 9, and 11 wk of age. Although stable beta-cell proliferation in Wistar and thymectomized BB rats was observed along the course of the study, a decrease in beta-cell proliferation and beta-cell mass from the age of 5 wk, and prior to the commencement of apoptosis, was noted in BB rats. Exendin-4, in combination with anti-interferon-gamma antibody, induced a near-total recovery of beta-cell proliferation during the initial stages of insulitis. This highlights the importance of early intervention and, as well, the possibilities of new therapeutic approaches in preventing autoimmune diabetes by acting, initially, in the insulitis stage and, subsequently, on beta-cell regeneration and on beta-cell apoptosis.

Reproductive allocation strategies: a long-term study on proximate factors and temporal adjustments in a viviparous lizard.

Optimisation of reproductive investment is crucial for Darwinian fitness, and detailed long-term studies are especially suited to unravel reproductive allocation strategies. Allocation strategies depend on the timing of resource acquisition, the timing of resource allocation, and trade-offs between different life-history traits. A distinction can be made between capital breeders that fuel reproduction with stored resources and income breeders that use recently acquired resources. In capital breeders, but not in income breeders, energy allocation may be decoupled from energy acquisition. Here, we tested the influence of extrinsic (weather conditions) and intrinsic (female characteristics) factors during energy storage, vitellogenesis and early gestation on reproductive investment, including litter mass, litter size, offspring mass and the litter size and offspring mass trade-off. We used data from a long-term study of the viviparous lizard, Lacerta (Zootoca) vivipara. In terms of extrinsic factors, rainfall during vitellogenesis was positively correlated with litter size and mass, but temperature did not affect reproductive investment. With respect to intrinsic factors, litter size and mass were positively correlated with current body size and postpartum body condition of the previous year, but negatively with parturition date of the previous year. Offspring mass was negatively correlated with litter size, and the strength of this trade-off decreased with the degree of individual variation in resource acquisition, which confirms theoretical predictions. The combined effects of past intrinsic factors and current weather conditions suggest that common lizards combine both recently acquired and stored resources to fuel reproduction. The effect of past energy store points out a trade-off between current and future reproduction.

Influence of anti-filarial chemotherapy strategies on the genetic structure of Wuchereria bancrofti populations

Lymphatic filarial (LF) parasites have been under anti-filarial drug pressure for more than half a century. Currently, annual mass drug administration (MDA) of diethylcarbamazine (DEC) or ivermectin in combination with albendazole (ALB) have been used globally to eliminate LF. Long-term chemotherapies exert significant pressure on the genetic structure of parasitic populations. We investigated the genetic variation among 210 Wuchereria bancrofti populations that were under three different chemotherapy strategies, namely MDA with DEC alone (group I, n = 74), MDA with DEC and ALB (group II, n = 60) and selective therapy (ST) with DEC (group III, n = 34) to understand the impact of these three drug regimens on the parasite genetic structure. Randomly amplified polymorphic DNA profiles were generated for the three groups of parasite populations; the gene diversity, gene flow and genetic distance values were determined and phylogenetic trees were constructed. Analysis of these parameters indicated that parasite populations under ST with a standard dose of DEC (group III) were genetically more diverse (0.2660) than parasite populations under MDA with DEC alone (group I, H = 0.2197) or with DEC + ALB (group II, H = 0.2317). These results indicate that the MDA may reduce the genetic diversity of W. bancrofti populations when compared to the genetic diversity of parasite populations under ST.

Alterations of specific biomarkers of metabolic pathways in vascular tree from patients with Type 2 diabetes.

The aims of this study were to check whether different biomarkers of inflammatory, apoptotic, immunological or lipid pathways had altered their expression in the occluded popliteal artery (OPA) compared with the internal mammary artery (IMA) and femoral vein (FV) and to examine whether glycemic control influenced the expression of these genes. The study included 20 patients with advanced atherosclerosis and type 2 diabetes mellitus, 15 of whom had peripheral arterial occlusive disease (PAOD), from whom samples of OPA and FV were collected. PAOD patients were classified based on their HbA1c as well (HbA1c ≤ 6.5) or poorly (HbA1c > 6.5) controlled patients. Controls for arteries without atherosclerosis comprised 5 IMA from patients with ischemic cardiomyopathy (ICM). mRNA, protein expression and histological studies were analyzed in IMA, OPA and FV. After analyzing 46 genes, OPA showed higher expression levels than IMA or FV for genes involved in thrombosis (F3), apoptosis (MMP2, MMP9, TIMP1 and TIM3), lipid metabolism (LRP1 and NDUFA), immune response (TLR2) and monocytes adhesion (CD83). Remarkably, MMP-9 expression was lower in OPA from well-controlled patients. In FV from diabetic patients with HbA1c ≤6.5, gene expression levels of BCL2, CDKN1A, COX2, NDUFA and SREBP2 were higher than in FV from those with HbA1c >6.5. The atherosclerotic process in OPA from diabetic patients was associated with high expression levels of inflammatory, lipid metabolism and apoptotic biomarkers. The degree of glycemic control was associated with gene expression markers of apoptosis, lipid metabolism and antioxidants in FV. However, the effect of glycemic control on pro-atherosclerotic gene expression was very low in arteries with established atherosclerosis.

Tire-breeding mosquitoes of public health importance along an urbanisation gradient in Buenos Aires, Argentina

Used vehicle tires are a source of mosquito vectors and a means of their introduction and expansion. With the aim of assessing the effects of urbanisation on the main mosquito vectors in temperate Argentina, the infestation levels of Aedes aegypti (L.) and Culex pipiens L. were studied in used tires from highly urbanised cities to low-urbanised small towns in Buenos Aires. Immatures of both species accounted for 96% of the 9,722 individuals collected; the total individuals collected represented seven species. The percentage of water-filled tires containing mosquitoes [container index (CI)] was 33% and the percentage of infested sites [site index (SI)] was 65.2%. These indexes decreased significantly from low to high urbanisation levels for both mosquito species. The relative abundance (RA) of Ae. aegypti immatures was slightly higher toward large cities, but showed no difference for Cx. pipiens. The CI of shaded tires was significantly higher than the CI of exposed tires for both mosquito species. There was no difference in RA values between shaded and sunlit tires. The CI and the SI were highest during the summer across the urbanisation levels, except for Cx. pipiens, which continued to increase during the autumn in small towns. Results related to urbanisation gradient, sunlit exposure and seasonality are discussed.

Optimising translational oncology in clinical practice: Strategies to accelerate progress in drug development.

Despite intense efforts, the socioeconomic burden of cancer remains unacceptably high and treatment advances for many common cancers have been limited, suggesting a need for a new approach to drug development. One issue central to this lack of progress is the heterogeneity and genetic complexity of many tumours. This results in considerable variability in therapeutic response and requires knowledge of the molecular profile of the tumour to guide appropriate treatment selection for individual patients. While recent advances in the molecular characterisation of different cancer types have the potential to transform cancer treatment through precision medicine, such an approach presents a major economic challenge for drug development, since novel targeted agents may only be suitable for a small cohort of patients. Identifying the patients who would benefit from individual therapies and recruiting sufficient numbers of patients with particular cancer subtypes into clinical trials is challenging, and will require collaborative efforts from research groups and industry in order to accelerate progress. A number of molecular screening platforms have already been initiated across Europe, and it is hoped that these networks, along with future collaborations, will benefit not only patients but also society through cost reductions as a result of more efficient use of resources. This review discusses how current developments in translational oncology may be applied in clinical practice in the future, assesses current programmes for the molecular characterisation of cancer and describes possible collaborative approaches designed to maximise the benefits of translational science for patients with cancer.

Strategies for the successful implementation of viral laboratory automation.

It has been estimated that more than 70% of all medical activity is directly related to information providing analytical data. Substantial technological advances have taken place recently, which have allowed a previously unimagined number of analytical samples to be processed while offering high quality results. Concurrently, yet more new diagnostic determinations have been introduced - all of which has led to a significant increase in the prescription of analytical parameters. This increased workload has placed great pressure on the laboratory with respect to health costs. The present manager of the Clinical Laboratory (CL) has had to examine cost control as well as rationing - meaning that the CL's focus has not been strictly metrological, as if it were purely a system producing results, but instead has had to concentrate on its efficiency and efficacy. By applying re-engineering criteria, an emphasis has had to be placed on improved organisation and operating practice within the CL, focussing on the current criteria of the Integrated Management Areas where the technical and human resources are brought together. This re-engineering has been based on the concepts of consolidating and integrating the analytical platforms, while differentiating the production areas (CORE Laboratory) from the information areas. With these present concepts in mind, automation and virological treatment, along with serology in general, follow the same criteria as the rest of the operating methodology in the Clinical Laboratory.

Identification of the natural breeding sites of sandflies (Diptera: Psychodidae: Phlebotominae), potential vectors of leishmaniasis, in the province of Chaco, Argentina

The aim of this work was to identify the natural breeding sites of sandflies in the province of Chaco, Argentina, for the first time. Preliminary studies were conducted in two different phytogeographic regions: dry Chaco (Parque Provincial Pampa del Indio), in January 2010, and humid Chaco (Resistencia, Margarita Belén and Colonia Benítez), from May-September 2010. A total of 127 samples were collected (Pampa del Indio: 15, Resistencia: 37, Margarita Belén: 36, Colonia Benítez: 39). A female of Migonemyia migonei was found in Pampa del Indio at the base of a bromeliad in the summer (January) and a pupal exuvium of a phlebotomine fly was found in Resistencia, in a place where dogs rested, in the winter (July). These findings highlighted these two sites as potential breeding sites. Because the existence of potential natural breeding sites for sandflies has been demonstrated in both forest and periurban areas, expanding the search efforts and characterising these sites will enable the development of specific study designs to gain insight into the spatial distribution of the risks posed by these vectors. The resulting information will serve as a basis for proposing and evaluating vector control measures.