Overview of latest articles and publications on ebola in PubMed. PubMed is a service of the US National Library of Medicine that includes over 18 million citations from MEDLINE and other life science journals.
- Annona muricata leaf extract-mediated silver nanoparticles synthesis and its larvicidal potential against dengue, malaria and filariasis vector.
Santhosh SB, Yuvarajan R, Natarajan D Annona muricata leaf extract-mediated silver nanoparticles synthesis and its larvicidal potential against dengue, malaria and filariasis vector. [JOURNAL ARTICLE]Parasitol Res 2015 May 24.Mosquitoes transmit several diseases which cause millions of deaths every year. The use of synthetic insecticides to control mosquitoes caused diverse effects to the environment, mammals, and high manufacturing cost. The present study was aimed to test the larvicidal activity of green synthesized silver nanoparticles using Annona muricata plant leaf extract against third instar larvae of three medically important mosquitoes, i.e., Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. The different concentrations of green synthesized Ag Nanoparticles (AgNPs; 6, 12, 18, 24, 30 μg mL(-1)) and aqueous crude leaf extract (30, 60, 90, 120, 150 μg mL(-1)) were tested against the larvae for 24 h. Significant larval mortality was observed after the treatment of A. muricata for all mosquitoes with lowest LC50 and LC90 values, viz., A. aegypti (LC50 and LC90 values of 12.58 and 26.46 μg mL(-1)), A. stephensi (LC50 and LC90 values of 15.28 and 31.91 μg mL(-1)) and C. quinquefasciatus (LC50 and LC90 values of 18.77 and 35.72 μg mL(-1)), respectively. The synthesized AgNPs from A. muricata were highly toxic than aqueous crude extract. The nanoparticle characterization was done using spectral and microscopic analysis, namely UV-visible spectroscopy which showed a sharp peak at 420 nm of aqueous medium containing AgNPs, X-ray diffraction (XRD) analysis revealed the average crystalline size of synthesized AgNPs (approximately 45 nm), and Fourier transform infrared spectroscopy (FTIR) study exhibited prominent peaks 3381.28, 2921.03, 1640.17, 1384.58, 1075.83, and 610.77 cm(-1). Particle size analysis (PSA) showed the size and distribution of AgNPs (103 nm); field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) analysis showed a spherical shape, size range from 20 to 53 nm; and energy-dispersive X-ray spectroscopy (EDX) reflects the chemical composition of synthesized AgNPs. Heat stability of the AgNPs was confirmed between the temperatures 20 to 70 °C. The result suggests that green synthesized AgNPs from A. muricata has the potential to be used as a low-cost and eco-friendly approach for the control of selected mosquitoes.
- Influence of antibodies and T cells on dengue disease outcome: insights from interferon receptor-deficient mouse models.
Tang WW, Grewal R, Shresta S Influence of antibodies and T cells on dengue disease outcome: insights from interferon receptor-deficient mouse models. [REVIEW]Curr Opin Virol 2015 May 19.:61-66.AbstractPublisher Full TextDengue virus (DENV) is a globally important mosquito-borne virus that causes a spectrum of diseases ranging from dengue fever (DF) to dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), affecting 3.6 billion people in 128 countries [1,2(•)]. There is an urgent need for a drug or vaccine against DENV, yet none are presently available. In fact, results from recent Phase IIb and III trials of an attenuated tetrameric vaccine revealed that the vaccine provided limited protection against DENV serotype 2 in DENV-immune people, and no protection against any serotype in naïve individuals [3-5], highlighting the difficulties associated with dengue vaccine development. A challenge in the development of a DENV vaccine is that a vaccine must protect against all four DENV serotypes, which co-circulate in endemic areas. Further complicating DENV vaccine development is that the correlates of protection are not fully defined, mechanisms regulating the generation of protective antibody and T cell responses against all four DENV serotypes are as yet to be deciphered, and the adaptive immune response may actually contribute to severe disease. Recent studies using the only available animal model of DHF/DSS in mice lacking one or more components of the interferon (IFN) system have begun to provide crucial insights into the protective versus pathogenic nature of both antibody and T cell responses to DENV. Herein, we highlight key studies using the IFN receptor-deficient mouse models toward understanding the contribution of antibodies and T cells in impacting the outcome of DENV infection.
- Transcriptome Profiling and Genetic Study Reveal Amplified Carboxylesterase Genes Implicated in Temephos Resistance, in the Asian Tiger Mosquito Aedes albopictus.
Grigoraki L, Lagnel J, Kioulos I, et al. Transcriptome Profiling and Genetic Study Reveal Amplified Carboxylesterase Genes Implicated in Temephos Resistance, in the Asian Tiger Mosquito Aedes albopictus. [JOURNAL ARTICLE]PLoS Negl Trop Dis 2015 May; 9(5):e0003771.AbstractPublisher Full TextThe control of Aedes albopictus, a major vector for viral diseases, such as dengue fever and chikungunya, has been largely reliant on the use of the larvicide temephos for many decades. This insecticide remains a primary control tool for several countries and it is a potential reliable reserve, for emergency epidemics or new invasion cases, in regions such as Europe which have banned its use. Resistance to temephos has been detected in some regions, but the mechanism responsible for the trait has not been investigated.Temephos resistance was identified in an Aedes albopictus population isolated from Greece, and subsequently selected in the laboratory for a few generations. Biochemical assays suggested the association of elevated carboxylesterases (CCE), but not target site resistance (altered AChE), with this phenotype. Illumina transcriptomic analysis revealed the up-regulation of three transcripts encoding CCE genes in the temephos resistant strain. CCEae3a and CCEae6a showed the most striking up-regulation (27- and 12-folds respectively, compared to the reference susceptible strain); these genes have been previously shown to be involved in temephos resistance also in Ae. aegypti. Gene amplification was associated with elevated transcription levels of both CCEae6a and CCEae3a genes. Genetic crosses confirmed the genetic link between CCEae6a and CCEae3a amplification and temephos resistance, by demonstrating a strong association between survival to temephos exposure and gene copy numbers in the F2 generation. Other transcripts, encoding cytochrome P450s, UDP-glycosyltransferases (UGTs), cuticle and lipid biosynthesis proteins, were upregulated in resistant mosquitoes, indicating that the co-evolution of multiple mechanisms might contribute to resistance.The identification of specific genes associated with insecticide resistance in Ae. albopictus for the first time is an important pre-requirement for insecticide resistance management. The genomic resources that were produced will be useful to the community, to study relevant aspects of Ae. albopictus biology.
- Thrombocytopenia in Dengue: Interrelationship between Virus and the Imbalance between Coagulation and Fibrinolysis and Inflammatory Mediators.
de Azeredo EL, Monteiro RQ, de-Oliveira Pinto LM Thrombocytopenia in Dengue: Interrelationship between Virus and the Imbalance between Coagulation and Fibrinolysis and Inflammatory Mediators. [REVIEW]Mediators Inflamm 2015.:313842.AbstractPublisher Full TextDengue is an infectious disease caused by dengue virus (DENV). In general, dengue is a self-limiting acute febrile illness followed by a phase of critical defervescence, in which patients may improve or progress to a severe form. Severe illness is characterized by hemodynamic disturbances, increased vascular permeability, hypovolemia, hypotension, and shock. Thrombocytopenia and platelet dysfunction are common in both cases and are related to the clinical outcome. Different mechanisms have been hypothesized to explain DENV-associated thrombocytopenia, including the suppression of bone marrow and the peripheral destruction of platelets. Studies have shown DENV-infected hematopoietic progenitors or bone marrow stromal cells. Moreover, anti-platelet antibodies would be involved in peripheral platelet destruction as platelets interact with endothelial cells, immune cells, and/or DENV. It is not yet clear whether platelets play a role in the viral spread. Here, we focus on the mechanisms of thrombocytopenia and platelet dysfunction in DENV infection. Because platelets participate in the inflammatory and immune response by promoting cytokine, chemokine, and inflammatory mediator secretion, their relevance as "immune-like effector cells" will be discussed. Finally, an implication for platelets in plasma leakage will be also regarded, as thrombocytopenia is associated with clinical outcome and higher mortality.
- Evidence-based vector control? Improving the quality of vector control trials.
Wilson AL, Boelaert M, Kleinschmidt I, et al. Evidence-based vector control? Improving the quality of vector control trials. [REVIEW]Trends Parasitol 2015 May 18.AbstractPublisher Full TextVector-borne diseases (VBDs) such as malaria, dengue, and leishmaniasis cause a high level of morbidity and mortality. Although vector control tools can play a major role in controlling and eliminating these diseases, in many cases the evidence base for assessing the efficacy of vector control interventions is limited or not available. Studies assessing the efficacy of vector control interventions are often poorly conducted, which limits the return on investment of research funding. Here we outline the principal design features of Phase III vector control field studies, highlight major failings and strengths of published studies, and provide guidance on improving the design and conduct of vector control studies. We hope that this critical assessment will increase the impetus for more carefully considered and rigorous design of vector control studies.
- Author’s reply.
Broor S Author’s reply. [Comment, Letter]J Vector Borne Dis 2015 Mar; 52(1):110.
- Zika Virus in an American Recreational Traveler.
Summers DJ, Acosta RW, Acosta AM Zika Virus in an American Recreational Traveler. [JOURNAL ARTICLE]J Travel Med 2015 May 21.We report the case of a 48-year-old American traveler who presented to our clinic with diffuse rash, malaise, fatigue, fever, arthralgia, low back pain, and bilateral exudative conjunctivitis. The patient had an extensive vaccination and travel history: most notable for prior receipt of yellow fever vaccine; extensive travel or residence in areas endemic for dengue, chikungunya, and West Nile virus; and recent travel to French Polynesia. Clinical and laboratory findings were consistent with Zika virus (ZIKV) infection. Our report highlights the need to include ZIKV in the differential diagnosis, especially in febrile patients with a rash returning from endemic areas.
- Arterial Hypertension and Skin Allergy Are Risk Factors for Progression from Dengue to Dengue Hemorrhagic Fever: A Case Control Study.
Teixeira MG, Paixão ES, Costa MD, et al. Arterial Hypertension and Skin Allergy Are Risk Factors for Progression from Dengue to Dengue Hemorrhagic Fever: A Case Control Study. [JOURNAL ARTICLE]PLoS Negl Trop Dis 2015 May; 9(5):e0003812.AbstractPublisher Full TextCurrently, knowledge does not allow early prediction of which cases of dengue fever (DF) will progress to dengue hemorrhagic fever (DHF), to allow early intervention to prevent progression or to limit severity. The objective of this study is to investigate the hypothesis that some specific comorbidities increase the likelihood of a DF case progressing to DHF.A concurrent case-control study, conducted during dengue epidemics, from 2009 to 2012. Cases were patients with dengue fever that progressed to DHF, and controls were patients of dengue fever who did not progress to DHF. Logistic regression was used to estimate the association between DHF and comorbidities.There were 490 cases of DHF and 1,316 controls. Among adults, progression to DHF was associated with self-reported hypertension (OR = 1.6; 95% CI 1.1-2.1) and skin allergy (OR = 1.8; 95% CI 1.1-3.2) with DHF after adjusting for ethnicity and socio-economic variables. There was no statistically significant association between any chronic disease and progression to DHF in those younger than 15 years.Physicians attending patients with dengue fever should keep those with hypertension or skin allergies in health units to monitor progression for early intervention. This would reduce mortality by dengue.
- Case series: Chikungunya and dengue at a forward operating location.
Reeves WK, Rowe NM, Kugblenu RK, et al. Case series: Chikungunya and dengue at a forward operating location. [Journal Article]MSMR 2015 May; 22(5):9-10.Publisher Full Text
- Efficient generation of monoclonal antibodies from single rhesus macaque antibody secreting cells.
Meng W, Li L, Xiong W, et al. Efficient generation of monoclonal antibodies from single rhesus macaque antibody secreting cells. [JOURNAL ARTICLE]MAbs 2015 May 21.:0.AbstractPublisher Full TextNonhuman primates (NHPs) are used as a preclinical model for vaccine development, and the antibody profiles to experimental vaccines in NHPs can provide critical information for both vaccine design and translation to clinical efficacy. However, an efficient protocol for generating monoclonal antibodies from single antibody secreting cells of NHPs is currently lacking. In this study we established a robust protocol for cloning immunoglobulin (IG) variable domain genes from single rhesus macaque (Macaca mulatta) antibody secreting cells. A sorting strategy was developed using a panel of molecular markers (CD3, CD19, CD20, surface IgG, intracellular IgG, CD27, Ki67 and CD38) to identify the kinetics of B cell response after vaccination. Specific primers for the rhesus macaque IG genes were designed and validated using cDNA isolated from macaque peripheral blood mononuclear cells. Cloning efficiency was averaged at 90% for variable heavy (VH) and light (VL) domains, and 78.5% of the clones (n=335) were matched VH and VL pairs. Sequence analysis revealed that diverse IGHV subgroups (for VH) and IGKV and IGLV subgroups (for VL) were represented in the cloned antibodies. The protocol was tested in a study using an experimental dengue vaccine candidate. About 26.6% of the monoclonal antibodies cloned from the vaccinated rhesus macaques react with the dengue vaccine antigens. These results validate the protocol for cloning monoclonal antibodies in response to vaccination from single macaque antibody secreting cells, which have general applicability for determining monoclonal antibody profiles in response to other immunogens or vaccine studies of interest in NHPs.