Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

Reaching the Hard-to-Reach: A Probability Sampling Method for Assessing Prevalence of Driving under the Influence after Drinking in Alcohol Outlets

Drinking alcoholic beverages in places such as bars and clubs may be associated with harmful consequences such as violence and impaired driving. However, methods for obtaining probabilistic samples of drivers who drink at these places remain a challenge – since there is no a priori information on this mobile population – and must be continually improved. This paper describes the procedures adopted in the selection of a population-based sample of drivers who drank at alcohol selling outlets in Porto Alegre, Brazil, which we used to estimate the prevalence of intention to drive under the influence of alcohol. The sampling strategy comprises a stratified three-stage cluster sampling: 1) census enumeration areas (CEA) were stratified by alcohol outlets (AO) density and sampled with probability proportional to the number of AOs in each CEA; 2) combinations of outlets and shifts (COS) were stratified by prevalence of alcohol-related traffic crashes and sampled with probability proportional to their squared duration in hours; and, 3) drivers who drank at the selected COS were stratified by their intention to drive and sampled using inverse sampling. Sample weights were calibrated using a post-stratification estimator. 3,118 individuals were approached and 683 drivers interviewed, leading to an estimate that 56.3% (SE = 3,5%) of the drivers intended to drive after drinking in less than one hour after the interview. Prevalence was also estimated by sex and broad age groups. The combined use of stratification and inverse sampling enabled a good trade-off between resource and time allocation, while preserving the ability to generalize the findings. The current strategy can be viewed as a step forward in the efforts to improve surveys and estimation for hard-to-reach, mobile populations

Sexual transmission of American trypanosomiasis in humans : a new potential pandemic route for Chagas parasites

Background: the Trypanosoma cruzi infection endemic in Latin America has now spread to several countries across four continents; this endemic involves triatomine vector-free protists. We hypothesised that the sexual transmission of T. cruzi contributes to the ongoing spread of Chagas disease. Objectives: a short-term longitudinal study was conducted to evaluate this hypothesis. Methods: the study population comprised 109 subjects from four families, among whom 21 had been diagnosed with acute Chagas disease by direct parasitological analysis. Blood mononuclear cells and serum samples were obtained from each study subject once per year for three consecutive years. Enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence serological examinations were used to detect specific T. cruzi antibodies. Polymerase chain reaction of T. cruzi DNA revealed 188-nucleotide bands, which hybridised to a specific radiolabelled probe and were confirmed by cloning and sequencing. Results: three independent assessments at different time points revealed T. cruzi nuclear DNA footprints in 76% (83/109) of the study population with active infection. In contrast, the ELISA and indirect immunofluorescence assays detected the T. cruzi antibody in 28.4% (31/109) of the study samples. Moreover, the semen from 82.6% (19/23) of subjects people revealed harboured the 188- bp base pair T. cruzi footprint. Interestingly, the ejaculates of nuclear DNA-positive Chagas patient transmitted the T. cruzi upon peritoneal injection or infusion in the vagina of mice, and amastigotes were detected in the skeletal muscle, myocardium, vas deferens, and uterine tube. Main conclusions: T. cruzi infections can be transmitted from females or males to naïve mates through intercourse, and progeny showed discrepancies between the ratios of nuclear DNA footprints and specific antibody that can be explained by the tolerance attained during early embryo growth. Additional studies are needed to develop drugs to eradicate the infections. Additionally, the importance of a vigorous education, information, and communication program to prevent sexually transmitted Chagas disease in humans cannot be underemphasised

Infected Dendritic Cells Facilitate Systemic Dissemination and Transplacental Passage of the Obligate Intracellular Parasite Neospora caninum in Mice

The obligate intracellular parasite Neospora caninum disseminates across the placenta and the blood-brain barrier, to reach sites where it causes severe pathology or establishes chronic persistent infections. The mechanisms used by N. caninum to breach restrictive biological barriers remain elusive. To examine the cellular basis of these processes, migration of different N. caninum isolates (Nc-1, Nc-Liverpool, Nc-SweB1 and the Spanish isolates: Nc-Spain 3H, Nc-Spain 4H, Nc-Spain 6, Nc-Spain 7 and Nc-Spain 9) was studied in an in vitro model based on a placental trophoblast-derived BeWo cell line. Here, we describe that infection of dendritic cells (DC) by N. caninum tachyzoites potentiated translocation of parasites across polarized cellular monolayers. In addition, powered by the parasite's own gliding motility, extracellular N. caninum tachyzoites were able to transmigrate across cellular monolayers. Altogether, the presented data provides evidence of two putative complementary pathways utilized by N. caninum, in an isolate-specific fashion, for passage of restrictive cellular barriers. Interestingly, adoptive transfer of tachyzoite-infected DC in mice resulted in increased parasitic loads in various organs, e.g. the central nervous system, compared to infections with free parasites. Inoculation of pregnant mice with infected DC resulted in an accentuated vertical transmission to the offspring with increased parasitic loads and neonatal mortality. These findings reveal that N. caninum exploits the natural cell trafficking pathways in the host to cross cellular barriers and disseminate to deep tissues. The findings are indicative of conserved dissemination strategies among coccidian apicomplexan parasites

Modeling the Dynamic Transmission of Dengue Fever: Investigating Disease Persistence

Dengue is the most rapidly spreading mosquito-borne viral disease in the world and approximately 2.5 billion people live in dengue endemic countries. In Brazil it is mainly transmitted by Aedes aegypti mosquitoes. The wide clinical spectrum ranges from asymptomatic infections or mild illness, to the more severe forms of infection such as dengue hemorrhagic fever or dengue shock syndrome. The spread and dramatic increase in the occurrence of dengue cases in tropical and subtropical countries has been blamed on uncontrolled urbanization, population growth and international traveling. Vaccines are under development and the only current disease control strategy is trying to keep the vector quantity at the lowest possible levels. Mathematical models have been developed to help understand the disease's epidemiology. These models aim not only to predict epidemics but also to expand the capacity of phenomena explanation. We developed a spatially explicit model to simulate the dengue transmission in a densely populated area. The model involves the dynamic interactions between humans and mosquitoes and takes into account human mobility as an important factor of disease spread. We investigated the importance of human population size, human renewal rate, household infestation and ratio of vectors per person in the maintenance of sustained viral circulation

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42\ub74% vs 44\ub72%; absolute difference \u20131\ub769 [\u20139\ub758 to 6\ub711] p=0\ub767; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5\u20138] vs 6 [5\u20138] cm H2O; p=0\ub70011). ICU mortality was higher in MICs than in HICs (30\ub75% vs 19\ub79%; p=0\ub70004; adjusted effect 16\ub741% [95% CI 9\ub752\u201323\ub752]; p<0\ub70001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0\ub780 [95% CI 0\ub775\u20130\ub786]; p<0\ub70001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status. Funding: No funding

Cannabidiol reduces host immune response and prevents cognitive impairments in Wistar rats submitted to pneumococcal meningitis

Pneumococcal meningitis is a life-threatening disease characterized by an acute infection affecting the pia matter, arachnoid and subarachnoid space. The intense inflammatory response is associated with a significant mortality rate and neurologic sequelae, such as, seizures, sensory-motor deficits and impairment of learning and memory. The aim of this study was to evaluate the effects of acute and extended administration of cannabidiol on pro-inflammatory cytokines and behavioral parameters in adult Wistar rats submitted to pneumococcal meningitis. Male Wistar rats underwent a cisterna magna tap and received either 10 mu l of sterile saline as a placebo or an equivalent volume of S. pneumoniae suspension. Rats subjected to meningitis were treated by intraperitoneal injection with cannabidiol (2.5, 5, or 10 mg/kg once or daily for 9 days after meningitis induction) or a placebo. Six hours after meningitis induction, the rats that received one dose were killed and the hippocampus and frontal cortex were obtained to assess cytokines/chemokine and brain-derived neurotrophic factor levels. On the 10th day, the rats were submitted to the inhibitory avoidance task. After the task, the animals were killed and samples from the hippocampus and frontal cortex were obtained. The extended administration of cannabidiol at different doses reduced the TNF-alpha level in frontal cortex. Prolonged treatment with canabidiol, 10 mg/kg, prevented memory impairment in rats with pneumococcal meningitis. Although descriptive, our results demonstrate that cannabidiol has anti-inflammatory effects in pneumococcal meningitis and prevents cognitive sequel. (C) 2012 Elsevier B.V. All rights reserved.CNPqFAPEMIGFAPESCUNESCNENASC project (PRONEX program CNPq/FAPESC)INCT-TMResearch Support Center on Applied Neuroscience (NAPNA-USP) [2011.1.9333.1.3]L'Oreal-UNESCO Brazil Fellowship for Women in Scienc