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.
- Bio-Conjugated Gold Nanoparticle Based SERS Probe for Ultrasensitive Identification of Mosquito-Borne Viruses Using Raman Fingerprinting.
Paul AM, Fan Z, Sinha SS, et al. Bio-Conjugated Gold Nanoparticle Based SERS Probe for Ultrasensitive Identification of Mosquito-Borne Viruses Using Raman Fingerprinting. [JOURNAL ARTICLE]J Phys Chem C Nanomater Interfaces 2015 Oct 15; 119(41):23669-23775.Dengue virus (DENV) and West Nile virus (WNV) are two well-documented mosquito-borne flaviviruses that cause significant health problems worldwide. Driven by this need, we have developed a bio-conjugated gold nanoparticle (AuNP)-based surface enhanced Raman spectroscopy (SERS) probe for the detection of both DENV and WNV. Reported data demonstrate anti-flavivirus 4G2 antibody conjugated gold nanoparticle (GNP) SERS probe can be used as a Raman fingerprint for the ultrasensitive detection of DENV and WNV selectively. Experimental data show that due to the plasmon coupling in nano-assembly, antibody conjugated GNP- based SERS is able to detect as low as 10 plaque-forming units (PFU)/ml of DENV-2 and WNV, which is comparable with the sensitivity of quantitative PCR-based assays. Selectivity of our probe was demonstrated using another mosquito-borne chikungunya virus (CHIKV) as a negative control. Experimental data demonstrate a huge enhancement of SERS intensity is mainly due to the strong electric field enhancement, which has been confirmed by the finite-difference time-domain (FDTD) simulation. Reported FDTD simulation data indicate the SERS enhancement factor can be more than 10(4) times, due to the assembled structure. Reported results suggest that bio-conjugated AuNP-4G2 based SERS probes have great potential to be used to screen viral particles in clinical and research-based laboratories.
- Historical environmental change in Africa drives divergence and admixture of Aedes aegypti mosquitoes: a precursor to successful worldwide colonisation?
Bennett KL, Shija F, Linton YM, et al. Historical environmental change in Africa drives divergence and admixture of Aedes aegypti mosquitoes: a precursor to successful worldwide colonisation? [JOURNAL ARTICLE]Mol Ecol 2016 Jul 20.AbstractPublisher Full TextIncreasing globalisation has promoted the spread of exotic species, including disease vectors. Understanding the evolutionary processes involved in such colonisations is both of intrinsic biological interest and important to predict and mitigate future disease risks. The Aedes aegypti mosquito is a major vector of dengue, chikungunya and Zika, the worldwide spread of which has been facilitated by Ae. aegypti's adaption to human-modified environments. Understanding the evolutionary processes involved in this invasion requires characterisation of the genetic makeup of the source population(s). The application of approximate Bayesian computation (ABC) to sequence data from four nuclear and one mitochondrial markers, revealed that African populations of Ae. aegypti best fit a demographic model of lineage diversification, historical admixture and recent population structuring. Since ancestral Ae. aegypti were dependent on forests, this population history is consistent with the effects of forest fragmentation and expansion driven by Pleistocene climatic change. Alternatively, or additionally, historical human movement across the continent may have facilitated their recent spread and mixing. ABC analysis and haplotype networks support earlier inferences of a single out of Africa colonisation event, while a cline of decreasing genetic diversity indicates that Ae. aegypti moved first from Africa to the Americas and then to Asia. ABC analysis was unable to verify this colonisation route, possibly because the genetic signal of admixture obscures the true colonisation pathway. By increasing genetic diversity and forming novel allelic combinations, divergence and historical admixture within Africa could have provided the adaptive potential needed for the successful worldwide spread of Ae. aegypti. This article is protected by copyright. All rights reserved.
- A Study on Spectrum of Hepatobiliary Dysfunctions and Pattern of Liver Involvement in Dengue Infection.
Bandyopadhyay D, Chattaraj S, Hajra A, et al. A Study on Spectrum of Hepatobiliary Dysfunctions and Pattern of Liver Involvement in Dengue Infection. [Journal Article]J Clin Diagn Res 2016 May; 10(5):OC21-6.The most common arthropod-borne viral (arboviral) disease in humans is dengue. It is transmitted by female Aedes mosquitoes. These mosquitoes are widely distributed in subtropical and tropical areas of the world. Study of dengue infection and its complications are rare from countries like India.In this prospective observational cross-sectional study, we intended to assess the frequency and degree of hepatobiliary dysfunction in adult patients with dengue infection presenting to a tertiary-care medical facility.The details of all patients with serologically proved dengue fever admitted to a tertiary care hospital in eastern India from July 2014 to June 2015 were prospectively reviewed. We collected data including routine blood count, Liver Function Test (LFT), Prothrombin Time (PT), Activated Partial Prothrombin Time (APTT), abdominal ultrasonography from 110 patients.The maximum number of cases were seen in the age group between 46 years and 61 years and of all cases 55.5% were male and 44.5% were female. Pain abdomen and vomiting were the commonest presenting complaints next to fever which was present in all the cases. Elevated liver enzymes, abnormal values of PT and APTT, thrombocytopenia were observed more commonly in Dengue Shock Syndrome (DSS). Gall bladder wall thickening, thrombocytopenia were seen more commonly in both DSS and Dengue Haemorrhagic Fever (DHF). Plasma leakage such as ascites and pleural effusion on USG were seen more frequently in patients with DHF (76.9% and 73.1%) followed by DSS (72% and 68%) and DF (33.9% and 32.2%).Hepatobiliary derangement is seen more commonly in severe case of dengue infection. Early recognition of these parameters can also be used as a predictor for assessing the disease severity.
- Seasonal and Geographical Variation of Dengue Vectors in Narathiwat, South Thailand.
Boonklong O, Bhumiratana A Seasonal and Geographical Variation of Dengue Vectors in Narathiwat, South Thailand. [Journal Article]Can J Infect Dis Med Microbiol 2016.:8062360.Using GIS-based land use map for the urban-rural division (the relative ratio of population density adjusted to relatively Aedes-infested land area), we demonstrated significant independent observations of seasonal and geographical variation of Aedes aegypti and Aedes albopictus vectors between Muang Narathiwat district (urban setting) and neighbor districts (rural setting) of Narathiwat, Southern Thailand, based on binomial distribution of Aedes vectors in water-holding containers (water storage containers, discarded receptacles, miscellaneous containers, and natural containers). The distribution of Aedes vectors was influenced seasonally by breeding outdoors rather than indoors in all 4 containers. Accordingly, both urban and rural settings elicited significantly seasonal (wet versus dry) distributions of Ae. aegypti larvae observed in water storage containers (P = 0.001 and P = 0.002) and natural containers (P = 0.016 and P = 0.015), whereas, in rural setting, the significant difference was observed in discarded receptacles (P = 0.028) and miscellaneous containers (P < 0.001). Seasonal distribution of Ae. albopictus larvae in any containers in urban setting was not remarkably noticed, whereas, in rural setting, the significant difference was observed in water storage containers (P = 0.007) and discarded receptacles (P < 0.001). Moreover, the distributions of percentages of container index for Aedes-infested households in dry season were significantly lower than that in other wet seasons, P = 0.034 for urban setting and P = 0.001 for rural setting. Findings suggest that seasonal and geographical variation of Aedes vectors affect the infestation in those containers in human inhabitations and surroundings.
- Vaccines and immunization strategies for dengue prevention.
Liu Y, Liu J, Cheng G Vaccines and immunization strategies for dengue prevention. [Journal Article, Review]Emerg Microbes Infect 2016; 5(7):e77.Dengue is currently the most significant arboviral disease afflicting tropical and sub-tropical countries worldwide. Dengue vaccines, such as the multivalent attenuated, chimeric, DNA and inactivated vaccines, have been developed to prevent dengue infection in humans, and they function predominantly by stimulating immune responses against the dengue virus (DENV) envelope (E) and nonstructural-1 proteins (NS1). Of these vaccines, a live attenuated chimeric tetravalent DENV vaccine developed by Sanofi Pasteur has been licensed in several countries. However, this vaccine renders only partial protection against the DENV2 infection and is associated with an unexplained increased incidence of hospitalization for severe dengue disease among children younger than nine years old. In addition to the virus-based vaccines, several mosquito-based dengue immunization strategies have been developed to interrupt the vector competence and effectively reduce the number of infected mosquito vectors, thus controlling the transmission of DENV in nature. Here we summarize the recent progress in the development of dengue vaccines and novel immunization strategies and propose some prospective vaccine strategies for disease prevention in the future.
- Association of genetic polymorphisms of IL1β -511 C>T, IL1RN VNTR 86 bp, IL6 -174 G>C, IL10 -819 C>T and TNFα -308 G>A, involved in symptomatic patients with dengue in Brazil.
Cansanção IF, do Carmo AP, Leite RD, et al. Association of genetic polymorphisms of IL1β -511 C>T, IL1RN VNTR 86 bp, IL6 -174 G>C, IL10 -819 C>T and TNFα -308 G>A, involved in symptomatic patients with dengue in Brazil. [JOURNAL ARTICLE]Inflamm Res 2016 Jul 19.AbstractPublisher Full TextIn this study, single nucleotide polymorphisms (SNP) of interleukin (IL) 1β -511C>T, IL1RN VNTR 86 bp, IL6 -174G>C, IL10 -819C>T and TNFα -308G>A were analyzed by PCR-RFLP with symptoms of dengue with the clinical features.196 individuals admitted to the São José Infectious Diseases Hospital with suspected dengue infection. Dengue was confirmed in 111 of the patients. The control group consisted of 85 other individuals confirmed without dengue.It was demonstrated that the presence the T allele of IL1β (P < 0.05) was associated with susceptibility to developing the disease. Other results also suggested that the polymorphism in the combinations IL6 × IL1β (C and T alleles, respectively), IL1β (T allele) × IL1RN (*2/*2 genotype), IL6 (C allele) × TNFα (A allele), IL10 (C/T genotype) × TNFα (A/A genotype) (P < 0.01, P = 0.01, P < 0.05 and P = 0.03, respectively) were associated with predisposition to developing the disease and its symptoms.In summary, the findings of this study in a Brazilian population point out the importance of studies of combinations of polymorphisms in the development of dengue, which can increase the risk of dengue infection and its severity.
- Dengue Virus Envelope Dimer Epitope Monoclonal Antibodies Isolated from Dengue Patients Are Protective against Zika Virus.
Swanstrom JA, Plante JA, Plante KS, et al. Dengue Virus Envelope Dimer Epitope Monoclonal Antibodies Isolated from Dengue Patients Are Protective against Zika Virus. [Journal Article]MBio 2016; 7(4)AbstractPublisher Full TextZika virus (ZIKV) is a mosquito-borne flavivirus responsible for thousands of cases of severe fetal malformations and neurological disease since its introduction to Brazil in 2013. Antibodies to flaviviruses can be protective, resulting in lifelong immunity to reinfection by homologous virus. However, cross-reactive antibodies can complicate flavivirus diagnostics and promote more severe disease, as noted after serial dengue virus (DENV) infections. The endemic circulation of DENV in South America and elsewhere raises concerns that preexisting flavivirus immunity may modulate ZIKV disease and transmission potential. Here, we report on the ability of human monoclonal antibodies and immune sera derived from dengue patients to neutralize contemporary epidemic ZIKV strains. We demonstrate that a class of human monoclonal antibodies isolated from DENV patients neutralizes ZIKV in cell culture and is protective in a lethal murine model. We also tested a large panel of convalescent-phase immune sera from humans exposed to primary and repeat DENV infection. Although ZIKV is most closely related to DENV compared to other human-pathogenic flaviviruses, most DENV immune sera (73%) failed to neutralize ZIKV, while others had low (50% effective concentration [EC50], <1:100 serum dilution; 18%) or moderate to high (EC50, >1:100 serum dilution; 9%) levels of cross-neutralizing antibodies. Our results establish that ZIKV and DENV share epitopes that are targeted by neutralizing, protective human antibodies. The availability of potently neutralizing human monoclonal antibodies provides an immunotherapeutic approach to control life-threatening ZIKV infection and also points to the possibility of repurposing DENV vaccines to induce cross-protective immunity to ZIKV.ZIKV is an emerging arbovirus that has been associated with severe neurological birth defects and fetal loss in pregnant women and Guillain-Barré syndrome in adults. Currently, there is no vaccine or therapeutic for ZIKV. The identification of a class of antibodies (envelope dimer epitope 1 [EDE1]) that potently neutralizes ZIKV in addition to all four DENV serotypes points to a potential immunotherapeutic to combat ZIKV. This is especially salient given the precedent of antibody therapy to treat pregnant women infected with other viruses associated with microcephaly, such as cytomegalovirus and rubella virus. Furthermore, the identification of a functionally conserved epitope between ZIKV and DENV raises the possibility that a vaccine may be able to elicit neutralizing antibodies against both viruses.
- Dengue suppresses MAVS.
Dempsey LA Dengue suppresses MAVS. [Journal Article]Nat Immunol 2016 Jul 19; 17(8):905.Publisher Full Text
- Unusual reversible oligomerization of unfolded Dengue envelope protein domain 3 at high temperature and its abolition by a point mutation.
Saotome T, Nakamura S, Islam MM, et al. Unusual reversible oligomerization of unfolded Dengue envelope protein domain 3 at high temperature and its abolition by a point mutation. [JOURNAL ARTICLE]Biochemistry 2016 Jul 19.AbstractPublisher Full TextHere we report DSC experiments between 10 and 120°C of Dengue 4 envelope protein domain 3 (DEN4 ED3), a small 107-residue monomeric globular protein domain. The thermal unfolding of DEN4 ED3 was fully reversible and exhibited two peculiar endothermic peaks. AUC (analytical ultracentrifugation) experiments at 25°C indicated that DEN4 ED3 was monomeric. Detailed thermodynamic analysis indicated that the two endothermic peaks separated away with increasing protein concentration, and global fitting of the DSC curves strongly suggested the presence of unfolded tetramers at temperatures around 80-90°C, which dissociated to unfolded monomers at even higher temperature. In order to further characterize this rare thermal unfolding process, we designed and constructed a DEN4 ED3 variant that would unfold according to a two-state model, typical of globular proteins. We thus substituted Val 380, the most buried residue at the dimeric interface in protein crystal, to less hydrophobic amino acids (Ala, Ser, Thr, Asn and Lys). All variants showed a single heat absorption peak, typical of small globular proteins. In particular, the DSC thermogram of DEN4 V380K indicated a two-state reversible thermal unfolding independent from protein concentration indicating that the high temperature oligomeric state was successfully abolished by a single mutation. These observations confirmed the standard view that small monomeric globular proteins undergo a two-state unfolding. However the reversible formation of unfolded oligomers at high temperature is a truly new phenomenon, which was fully inhibited by an accurately designed single mutation.
- Insect-specific flavivirus infection is restricted by innate immunity in the vertebrate host.
Tree MO, McKellar DR, Kieft KJ, et al. Insect-specific flavivirus infection is restricted by innate immunity in the vertebrate host. [JOURNAL ARTICLE]Virology 2016 Jul 16.:81-91.AbstractPublisher Full TextArboviruses are a large group of viruses that are transmitted by arthropods including ticks and mosquitoes. The global diversity of arboviruses is unknown; however, theoretical studies have estimated that over 2,000 mosquito-borne flaviviruses may exist. An increasing number of flaviviruses can only infect insect cells. We hypothesize that insect-specific flaviviruses (ISFVs) represent model genetic precursors to pathogenic flaviviruses, although the genetic mechanisms required for adaptation to vertebrate hosts are unclear. In this study, we determined that Kamiti River virus (KRV) infection was inhibited by innate immunity pathways in vertebrate cells. KRV infection of IRF3,5,7(-/-) mouse embryonic fibroblasts led to low levels of viral protein production and shedding of infectious progeny. These data suggest that ISFVs cannot evade vertebrate innate immune pathways. Identifying cellular pathways and genetic changes that are required for adaptation of arthropod-specific arboviruses to vertebrate hosts is critical to understanding emerging infectious disease.